Science says you may need less exercise than you think to live a long and healthy life.For anyone interested in the relationship between exercise and living longer, one of the most pressing questions is how much we really need to stay healthy. Is 30 minutes a day enough? Can we get by with less? Do we have to exercise all in one session, or can we spread it throughout the day? And when we’re talking about exercise, does it have to be hard to count?For years, exercise scientists tried to quantify the ideal “dose” of exercise for most people. They finally reached a broad consensus in 2008 with the Physical Activity Guidelines for Americans, which were updated in 2018 after an extensive review of the available science about movement, sitting and health. In both versions, the guidelines advised anyone who was physically able to accumulate 150 minutes of moderate exercise every week, and half as much if it is intense.But what’s the best way to space out those weekly minutes? And what does “moderate” mean? Here’s what some of the leading researchers in exercise science had to say about step counts, stairwells, weekend warriors, greater longevity and why the healthiest step we can take is the one that gets us off the couch.Aim for the 150-minute sweet spot.“For longevity, 150 minutes a week of moderate to vigorous intensity physical activity clearly is enough,” said Dr. I-Min Lee, a professor of epidemiology at the Harvard T.H. Chan School of Public Health. She has extensively studied movement and health and helped draft the current national physical activity guidelines.For practical purposes, exercise scientists often recommend breaking that 150 minutes into 30-minute sessions of speedy walking or a similar activity five times a week. “It is quite clear from numerous large-scale, well-conducted epidemiological studies that 30 minutes of moderate-intensity activity most days lowers the risk of premature death and many diseases, such as stroke, heart attack, Type 2 diabetes and many types of cancer,” said Ulf Ekelund, a professor specializing in physical activity epidemiology at the Norwegian School of Sports Sciences in Oslo, who has led many of those studies.Moderate exercise, he continued, means “activities that increase your breathing and heart rate, so the exertion feels like a five or six on a scale between one and 10.” In other words, pick up the pace a bit if your inclination is to stroll, but do not feel compelled to sprint.Consider exercise snacks.You also can break up your exercise into even smaller segments. “It doesn’t matter whether exercise is done in a long, continuous 30-minute session or is dispersed across the day in shorter sessions,” said Emmanuel Stamatakis, an exercise scientist at the University of Sydney in Australia who studies physical activity and health.Recent studies overwhelmingly show that we can accumulate our 150 weekly minutes of moderate exercise in whatever way works best for us, he said. “Many people may find it easier and more sustainable to squeeze in a few dozen one-minute or two-minute walks between work tasks” or other commitments. “There is no special magic to a sustained 30-minute session of exercise” for most health benefits.Think of these bite-size workouts as exercise snacks, he said. “Activities like bursts of very fast walking, stair climbing and carrying shopping bags provide excellent opportunities for movement snacks.” To concentrate the health benefits of these workout nuggets, he added, keep the intensity relatively high, so you feel somewhat winded.Conceivably, you also could cram all of your exercise into long Saturday and Sunday workouts. In a 2017 study by Dr. Stamatakis and colleagues, people who reported exercising almost entirely on weekends were less likely to die prematurely than those who said they rarely exercised at all. But being a weekend warrior has drawbacks. “It is certainly not ideal to spend the workweek totally sedentary and then try to compensate” over the weekend, Dr. Stamatakis said. You miss many of the health benefits of regular exercise, such as improved blood-sugar control and better moods, on the days you do not work out, he said. You also increase your risk of exercise-related injuries.Count your steps.The exercise recommendations remain the same if you measure your exercise in steps instead of minutes. For most people, “150 minutes of exercise a week would translate into about 7,000 to 8,000 steps a day,” Dr. Lee said. In a large-scale new study by Dr. Lee and Dr. Ekelund of the relationship between steps and longevity, published in March in The Lancet, the optimal step count for people younger than 60 was about 8,000 to 10,000 a day, and for those 60 and over, it was about 6,000 to 8,000 a day.Consider more.Of course, these recommendations about steps and minutes focus on health and life spans, not physical performance. “If you want to run a marathon or a 10K race as fast as possible, you need much more exercise,” Dr. Ekelund said.The recommended 150 minutes a week also may be too little to stave off weight gain with age. In a 2010 study of almost 35,000 women that was spearheaded by Dr. Lee, only those who walked or otherwise exercised moderately for about an hour a day during middle age maintained their weight as they became older.So, if you have the time and inclination, move more than 30 minutes a day, Dr. Lee and the other scientists said. In general, according to her research and other studies, the more active we are, well beyond 30 minutes a day, the more our risks of chronic diseases drop and the longer our lives may be.But any activity is better than none. “Every single minute counts,” Dr. Ekelund said. “Walking up the stairs has health benefits, even if it only lasts for one or two minutes, if you repeat it regularly.”Gretchen Reynolds will be taking time off from the PhysEd column to work on a book. In the meantime, follow her on Twitter (@gretchenreynold) or look for her on the running trails and bike paths.

In her new book, Jennifer Heisz blends personal experience and the latest science about how exercise can improve your mental well-being.When Jennifer Heisz was in graduate school, she borrowed a friend’s aged, rusty road bike — and wound up redirecting her career. At the time, she was studying cognitive neuroscience but, dissatisfied with the direction of her work and her personal life, began experiencing what she now recognizes as “pretty severe anxiety,” she told me recently. Her friend suggested biking as a reprieve. Not previously athletic, she took to the riding with enthusiasm, finding it “soothed my mind,” she said.That discovery convinced her to change the focus of her research. Now the director of the NeuroFit Lab at McMaster University in Hamilton, Ontario, she studies the interplay of physical and emotional health and how exercise helps stave off or treat depression, anxiety, stress and other mental health conditions.“The effects of motion on the mind are just so pervasive and fascinating,” said Dr. Heisz.That idea animates her new book, “Move the Body, Heal the Mind,” which details the latest science about exercise and mental health, as well as her own journey from inactivity and serial emotional slumps to triathlon training and increasing serenity. Recently, I caught up with Dr. Heisz to talk about her book and what it can tell us about mental health, the benefits of gentle exercise, the strains of the pandemic years and how to choose the right workout, right now, to raise your spirits. Our edited conversation follows.Can we talk about exercise and anxiety, which many of us are feeling these days?JH: Exercise is extremely beneficial for reducing anxiety. At the end of every workout, in fact, you typically get a brief reprieve from anxiety, due to neuropeptide Y, which increases with exercise. It’s a resiliency factor. It helps soothe the anxious amygdala, which is the part of the brain that recognizes danger and puts us on high alert. For the last few years, with the pandemic, our amygdala has been on hyper-alert, setting off an almost constant stress response. This chronicity of stress starts to make our minds really fearful and you wind up with constant anxiety. Exercise, by up-regulating neuropeptide Y, helps soothe the anxious amygdala, dial down the fear and hyper-vigilance and keep us calmer.Any particular type of exercise?JH: The really nice thing is that light to moderate exercise, like walking, is enough. Research from my lab shows this kind of exercise reduces anxiety immediately after your workout and then, over time, if you keep exercising, reduces anxiety even more and for longer. It looks like about 30 minutes of this kind of exercise three times a week is good. Walking, cycling, swimming, dancing — a wide variety of activities work.At her Ontario workout laboratory, Dr. Heisz has found that exercise is directly tied to lower depression and anxiety.Narisa Ladak for The New York TimesWhat about more intense workouts?JH: You need to be careful with really intense exercise and anxiety. If you’re feeling anxiety, you’re already under stress. High-intensity exercise is also a kind of stress. But our bodies only have, in general, one stress response. So, during intense exercise, you add extreme physical stress onto the stress your body already is feeling and it might all become too much. Right before the pandemic, I was training for a triathlon and doing a lot of high-intensity workouts. But once the pandemic started, I was feeling so much emotional stress, I couldn’t finish those workouts. So, I backed off. What I would tell people is that, when you’re already feeling stressed-out, prolonged, intense exercise may not be the right option.What would you recommend people do instead?JH: Aim for exercise that feels comfortably challenging, so your heart rate is elevated but not racing. For a lot of people, that would mean taking a brisk walk around the park or the block.Does exercise help in the same ways against depression?JH: Classically, depression has been blamed on a lack of serotonin in the brain, which anti-depressants treat. But for some people with depression the drugs don’t work well, probably because serotonin is not their problem. Many of us who study depression now think their problem may involve inflammation, which is linked to stress. The inflammation starts to damage cells in the body, inducing an immune response and increasing inflammation, which can then get into the brain, affecting mood. For those people, exercise may be the medicine they need, because it helps fight the inflammation. In studies, when individuals who haven’t responded to anti-depressants start exercising, they usually see significant reductions in their symptoms.How much exercise are we talking about?JH: One study that looked at frequency, or how much exercise you need to combat depression, compared 150 minutes of moderate to vigorous exercise a week, which is the standard exercise recommendation for physical health, with a quarter of that. And both groups benefited the same. So, it looks like the exercise prescription for mental health is less than that for physical health, which is kind of nice.In terms of helping to potentially combat depression, do you think the exercise intensity matters?JH: It might. We conducted a study a few years ago with healthy students who were facing high-pressure final exams. Some of them rode stationary bicycles moderately three times a week for 30 minutes and others did shorter, more-intense interval cycling. A third group didn’t exercise at all. After six weeks, the students who hadn’t worked out showed symptoms of fairly serious depression, which had come on shockingly fast, and presumably from their academic stress. The students who had been exercising moderately, though, were less stressed out than they had been at the start of the study and their bodies’ inflammation levels were lower. But what’s really interesting to me is that the intense exercisers showed symptoms of increased stress, both physical and mental. So, it does look as if moderate exercise may be the most beneficial for mental health.You talk frankly in your book about your own bouts of anxiety, stress and obsessive compulsive disorder, including after the birth of your daughter and, later, your divorce. Did exercise help you cope?JH: It’s the key. Mental illness can happen to anyone, even people who seem to be handling things well. For me and many other people, life transitions, like divorce and childbirth, can be especially challenging. After my divorce, I really needed something to redirect my life. And I knew how potently exercise, as a stimulus, alters the brain. Someone mentioned triathlons. I was still biking then. So, I added in the running and swimming.And qualified for the World Championships?JH: Eventually, yes. But it took years. Then the championships were delayed by the pandemic and now I’m out of shape and will have to start training all over again. But that’s something to look forward to, really. What I find is that, in times like these, there is solace in exercise. In the peaceful moments after a workout, hope is alive. You feel like the world is right again. And that’s really special.

Men and women who briefly contracted their arm muscles as hard as possible once daily increased their biceps strength by up to 12 percent in a month.Could three seconds a day of resistance exercise really increase muscular strength?That question was at the heart of a small-scale new study of almost comically brief weight training. In the study, men and women who contracted their arm muscles as hard as possible for a total of three seconds a day increased their biceps strength by as much as 12 percent after a month.The findings add to mounting evidence that even tiny amounts of exercise — provided they are intense enough — can aid health. I have written about the unique ways in which our muscles, hearts, lungs and other body parts respond to four seconds of strenuous biking, for instance, or 10 seconds of all-out sprinting, and how such super-short workouts can trigger the biological responses that lead to better fitness.But almost all of this research focused on aerobic exercise and usually involved interval training, a workout in which spurts of hard, fast exertion are repeated and interspersed with rest. Far less research has delved into super-brief weight training or whether a single, eyeblink-length session of intense resistance exercise might build strength or just waste valuable seconds of our lives.So, for the new study, which was published in February in the Scandinavian Journal of Medicine & Science in Sports, scientists led by Masatoshi Nakamura at the Niigata University of Health and Welfare in Niigata, Japan, asked 39 sedentary but otherwise healthy college students to do three seconds of weight training every day. They also recruited an additional 10 students who would not work out to serve as a control group.The exercising volunteers gathered during the workweek at the lab for strength testing and weight lifting, of a kind. They sat at a machine called an isokinetic dynamometer, which has a long lever arm that can be pushed and pulled, up or down, with varying levels of resistance, allowing researchers to precisely control people’s movements and effort.The volunteers manipulated the weighted lever with all their strength, straining and contracting their biceps to the fullest possible extent. Some of the participants slowly lifted the lever’s weight, like curling a dumbbell, producing what is called a concentric contraction, meaning the biceps shortened as they worked. Other volunteers slowly lowered the lever, creating a so-called eccentric contraction. You get an eccentric contraction when you lengthen a muscle, like lowering a dumbbell during a curl, and it tends to be more draining. A third group of volunteers held the lever’s weight steady in midair, fighting gravity, in a type of contraction where the muscle doesn’t change length at all.And each of the participants did their biceps exercise for a total of three seconds.That was it; that was their entire daily workout. They repeated this exceedingly brief exercise routine once a day, five times a week, for a month, for a grand total of 60 seconds of weight training. They did not otherwise exercise.At the end of the month, the researchers retested everyone’s arm strength.Those three-second sessions had changed people’s biceps. The groups either lifting or holding the weights were between 6 and 7 percent stronger. But those doing eccentric contractions, lowering the lever downward as you might ease a dumbbell away from your shoulder, showed substantially greater gains. Their biceps muscles were nearly 12 percent stronger overall.These improvements may sound slight, but they would be biologically meaningful, especially for people new to weight training, said Ken Nosaka, a professor of exercise and sports science at Edith Cowan University in Joondalup, Australia, who collaborated on the study. “Many people do not do any resistance training,” and starting with very short workouts may be an effective way for them to begin a strength training regimen, Dr. Nosaka said. “Every muscle contraction counts” and contributes to building strength, assuming you lift a weight near the maximum you can handle and it lasts at least three seconds, he said.The three-second workout could also be useful as a stopgap to help maintain or even add to our arm strength for those of us who are buried under work or family commitments and are unable to get to the gym.The exercise routine is easy enough to recreate at home, Dr. Nosaka said, no dynamometer needed. Just find a dumbbell that feels heavy — you might start with a 10-pound version, for instance, if you are new to weight training. “Lift it with both hands,” Dr. Nosaka said, to start a biceps curl, then “lower it with one hand” through a count of three seconds to complete a short, sharp and draining eccentric contraction.This approach, though, has some obvious limitations. While the volunteers in the study got stronger, they did not add muscle mass. “Strength is only one outcome” of resistance exercise, said Jonathan Little, a professor of health and exercise science at the University of British Columbia in Kelowna, who has studied brief workouts but was not involved with this experiment. More traditional weight training typically also bulks up muscles, which has additional benefits for metabolism and other aspects of health and wellness over the long term.The study also looked only at people’s biceps. Whether other muscles, especially in the legs, would strengthen after a few intense seconds of “lifting” is uncertain. More broadly, framing exercise as something that should be dispensed with as quickly as possible could make workouts seem like just another chore and maybe easier to skip.Dr. Nosaka said he and his colleagues plan to study whether repeating three-second contractions multiple times throughout the day increases muscle mass, as well as strength. They are also exploring how to translate this approach to the legs and other muscles.In the meantime, he said, we should probably think of three seconds of daily strength training as the least we can do. “It is definitely better,” he said, “to do one contraction a day than nothing.”

People who worked out in even moderately polluted air did not show the kinds of brain improvements tied to a lower risk of dementia.Work out in polluted air and you may miss out on some of the brain benefits of exercise, according to two, large-scale new studies of exercise, air quality and brain health. The studies, which involved tens of thousands of British men and women, found that, most of the time, people who ran and rode vigorously had larger brain volumes and lower risks for dementia than their less active peers. But if people exercised in areas with even moderate levels of air pollution, the expected brain improvements from exercise almost disappeared.The new studies raise questions about how to balance the undeniable health gains of working out with the downsides of breathing in bad air and underscore that our environment can change what exercise does — and does not do — for our bodies.A large body of evidence demonstrates that, on the whole, exercise bulks up our brains. In studies, active people generally sport more gray matter in many parts of their brains than sedentary people. Gray matter is made up of the brain’s essential, working neurons. Fit people also tend to have healthier white matter, meaning the cells that support and connect neurons. White matter often frays with age, shrinking and developing Swiss-cheese-like lesions even in healthy adults. But fit people’s white matter shows fewer and smaller lesions.Partially as a consequence of these brain changes, exercise is strongly linked with lower risks for dementia and other memory problems with age.But air pollution has the opposite effects on brains. In a 2013 study, for example, older Americans living in areas with high levels of air pollution showed bedraggled white matter on brain scans and tended to develop higher rates of mental decline than older people living elsewhere. And in a 2021 study of rats housed in cages placed near a heavily trafficked, exhaust-clogged road tunnel in Northern California, most of those bred with a predisposition to a rodent analogue of Alzheimer’s disease soon developed dementia. But so did another set of rats with no genetic inclination to the disease.Few studies, though, had explored how exercise and air pollution might interact inside our skulls and whether working out in smoggy air would protect our brains from noxious fumes or undermine the good we otherwise gain from working out.So, for the first of the new studies, published in January in Neurology, researchers at the University of Arizona and University of Southern California pulled records for 8,600 middle-aged adults enrolled in the UK Biobank. A huge trove of health and lifestyle records, the Biobank holds information on about more than 500,000 British adults, such as their ages, home locations, socioeconomic status, genomes and extensive health data. Some of the participants also completed brain scans and wore activity monitors for a week to track their exercise habits.The researchers focused on those who had worn a monitor, had a brain scan and, according to their trackers, often exercised vigorously, such as by running, which meant they breathed heavily during workouts. The heavier you breathe, the more air pollutants you draw in. The researchers also included some people who never worked out vigorously, for comparison.Using established air quality models, they then estimated air pollution levels where the people lived and, finally, compared everyone’s brain scans.Disappearing benefitsAs expected, vigorous exercise was linked, in general, to sturdy brain health. Men and women who lived and presumably worked out in areas with little air pollution showed relatively large amounts of gray matter and low incidence of white matter lesions, compared to people who never exercised hard. And the more they exercised, the better their brains tended to look.But any beneficial associations almost disappeared when exercisers lived in areas with even moderate air pollution. (Levels in this study were mostly within the bounds considered acceptable for health by European and American air quality standards.) Their gray matter volume was smaller and white matter lesions more numerous than among people living and exercising away from pollution, even if their workouts were similar.Extending these findings in a second, follow-up study published this month in Medicine & Science in Sports & Exercise, the same scientists repeated aspects of this experiment with another 35,562 older UK Biobank participants, comparing people’s exercise habits, local pollution levels and diagnoses of dementia, if any. The data showed the more people exercised, the less likely they were to develop dementia over time — provided their local air was clear. When it was moderately polluted, though, they had an increased long-term risk of dementia, whether they exercised or not.Keith E. Morrison for The New York Times‘Alarming’ finding“These data are of significant importance in terms of our understanding of modifiable risk factors for brain aging,” said Pamela Lein, a professor of neurotoxicity at the University of California, Davis, who led the earlier study of rats and pollution. She was not involved with the new studies. “The observation that air pollution negates the well-established beneficial effects of exercise on brain health is alarming and increases the urgency for developing more-effective regulatory policies” related to air quality.The studies have limitations. They are observational and show links between exercise, pollution and brain health, but cannot prove that bad air directly counteracts the brain benefits of exercise, or how this might occur. They also did not look into where people worked out, only that some lived in places with iffy air.But the results do intimate that the quality of the air influences the results of the workout and that for the sake of our brains, we should try not to exercise in bad air, said David Raichlen, a professor of biological sciences at U.S.C. and co-author of the new studies.Boosting brain healthIn practice, a number of measures may help to bolster the brain benefits of exercise, experts say.“Stay away from busy highways, if at all possible,” Dr. Raichlen said. Automobile exhausts are among the worst pollutants for human health.Check local conditions at airnow.gov, which uses the color-coded Air Quality Index to rate air quality by ZIP code. Most weather apps also include the local A.Q.I. Aim to workout in air quality rated as Green, which is Good. Air quality changes throughout the day, so check back in a few hours if conditions seem unfavorable at first.Working out indoors may be no better. “The available evidence suggests pollution levels indoors are about the same as those outside,” Dr. Raichlen said, unless a building, such as a gym, has installed extensive air filtration systems. Pollutants can readily enter buildings through open doors or windows or cracks in the structure, and the government doesn’t routinely monitor indoor air quality. You can learn more at the Environmental Protection Agency website.Masking might help. Both surgical and N95 masks filter some unhealthy particulates, such as soot and other matter, said Melissa Furlong, an environmental epidemiologist at the University of Arizona and co-author of the two studies. “If you don’t mind wearing a mask while exercising,” she said, “this would likely result in a reduction of exposure to particulates.”Most important, keep exercising. Exercise has multiple benefits for cardiovascular health, and “we do not want to discourage people from being physically active,” Dr. Raichlan said, even if air conditions are not ideal. In the new studies, the brains of people who exercised in polluted air looked no better, he pointed out — but their brains were also no worse than those of people who did not exercise at all.So, if your only opportunity to exercise is with some pollution hanging in the air, don a mask and go. Then check your local A.Q.I. forecast to look for clearer conditions in the future. The better the air quality is around you as you exercise, Dr. Raichlen said, the better the workout will be for your brain.

A 90-minute walk, jog or bike ride after getting vaccinated may boost your body’s immune response.Taking a long, brisk walk, jog or bike ride after your next Covid or flu vaccine might amplify the benefits of the shot, according to a new study of exercise and immunization. The study, which involved 70 people and about 80 mice, looked at antibody responses after a jab with the influenza vaccine or both rounds of the Pfizer-BioNTech Covid-19 vaccine. It found that people who exercised for 90 minutes right after their shot subsequently produced more antibodies than people who did not. The extra immune boost, which should help reduce their risk of falling seriously ill from those diseases, did not seem to trigger an increase in side effects.The study’s results are preliminary and need to be tested in larger numbers of people. But the findings add to mounting evidence that being fit and physically active may prime our bodies to respond with extra robustness to flu and Covid vaccines.Exercise alters ‘almost all’ our immune cells.The relationship between exercise and immunity is, in general, well established. Most studies show that being physically active helps protect us against catching colds and other mild, upper-respiratory tract infections. Being fit may also ease the severity of an infection if we do get sick. In a study last year of almost 50,000 Californians who developed Covid, for example, those who had been exercising regularly before their diagnosis were about half as likely to wind up hospitalized as people who rarely worked out.On the other hand, extreme exercise might undermine our immunity. Marathon runners often report getting sick after races, and lab mice that run to utter exhaustion tend to become more susceptible to the flu than sedentary animals.Overall, though, exercise appears to offer a potent boost to our immune systems. “The behavior of almost all immune cell populations in the bloodstream is altered in some way during and after exercise,” a recent review of past research on the topic concluded.Today’s 3 Key Reads About Covid1. Mask Mandates: Democratic governors are racing to ease Covid rules, mindful that voters want to get on with life.2. How Americans Feel: The U.S. public is frustrated with the pandemic. A wave of new polls shows how much.3. J&J Vaccine: The company quietly paused vaccine production despite a persistent need in much of the developing world.So, it should not be surprising that exercise might also affect vaccine response. In some past studies, performing arm exercises before a flu shot upped the levels of antibodies and specialized immune cells afterward more than sitting quietly. And in a 2020 study, elite competitive athletes in the middle of their training seasons generated more antibodies and immune cells after a flu shot than a control group of healthy young people.Is there a right ‘dose’ of exercise?But few of these earlier studies aimed to suss out the best timing and amounts of exercise to amplify vaccine effects, and none looked at Covid shots, which have only been available since late 2020. So, for the new study, published this week in Brain, Behavior, and Immunity, a group of immunobiologists and exercise scientists at Iowa State University in Ames, Iowa, asked people getting a flu or Covid shot to also work out.They began by inviting dozens of healthy adults aged 18 to 87 who said they exercised occasionally to come to the lab for a flu shot. The scientists also coordinated with local Covid vaccination sites to recruit 28 men and women who were getting their first Covid shots. Before the vaccinations, they drew blood from all the volunteers to check antibody levels.Then they randomly assigned everyone either to sit quietly or to exercise for 90 minutes after getting their shot. Earlier research had suggested that exercising after getting a vaccine increased the immune response more than the same level of activity beforehand. And they settled on 90 minutes as a general exercise target because unpublished research from their lab suggested that amount of exercise substantially increased the production of a substance in the blood called interferon alfa that can spark the creation of immune cells.The exercising volunteers then rode a stationary bike or walked rapidly for 90 minutes after their vaccinations, either at the lab or outside on the sidewalks near the Covid vaccine sites. They worked out at a mildly challenging pace, aiming to keep their heart rates between about 120 and 140 beats per minute. But the researchers also asked some of the flu-shot volunteers to ride for only 45 minutes, to see if the shorter workout might be equally effective at amping immunity.Because antibody levels tend to build in the weeks following a vaccination, the researchers drew blood from everyone again two and four weeks after their shots. (People getting the Covid vaccine received their second shot in the interim, since a second Pfizer shot should be given three weeks after the first.)45 minutes is not enough.After a month, everyone’s antibody levels to the flu or Covid shot rose substantially, as expected after getting a vaccine. But they were highest in the men and women who had exercised for 90 minutes afterward. This antibody bonus was not huge. “But it was statistically significant,” said Marian Kohut, a professor of kinesiology and member of the Nanovaccine Institute at Iowa State, who oversaw the new study.People who exercised also did not report additional side effects after their shots. (They did not experience fewer side effects, either.)The Coronavirus Pandemic: Key Things to KnowCard 1 of 4Mask mandates ending.

Ten minutes of moderate exercise daily would prevent more than 111,000 premature deaths a year, a new analysis found.If almost all of us started walking for an extra 10 minutes a day, we could, collectively, prevent more than 111,000 deaths every year, according to an enlightening new study of movement and mortality. Published this week in JAMA Internal Medicine, the study used data about physical activity and death rates for thousands of American adults to estimate how many deaths every year might be averted if everyone exercised more. The results indicate that even a little extra physical activity by each of us could potentially stave off hundreds of thousands of premature deaths over the coming years.Already, science offers plenty of evidence that how much we exercise influences how long we live. In a telling 2019 study published by the Centers for Disease Control and Prevention, more than 8 percent of all deaths in the United States were attributed to “inadequate levels of activity.” A British study from 2015 likewise found that men and women who exercised for at least 150 minutes per week — the standard recommendation in Britain, Europe and the United States — reduced their risk of premature death by at least 25 percent compared to people who exercised less. More dramatically, a 2020 examination of the lifestyles and death risks of about 44,000 adults in the United States and Europe concluded that the most sedentary men and women in the study, who sat almost all day, were as much as 260 percent more likely to die prematurely as the most highly active people studied, who exercised for at least 30 minutes most days.But much of this past research relied on people’s often unreliable memories of their exercise and sitting habits. In addition, many of the studies that delved into the broader, population-level impacts of exercise on longevity tended to use formal exercise guidelines as their goal. In those studies, researchers modeled what would happen if everyone started working out for at least 150 minutes a week, an ambitious and perhaps unachievable goal for the many people who previously have exercised rarely, if at all.In the new study, researchers at the National Cancer Institute and the C.D.C. decided instead to explore what might happen to death rates if people started moving around more, even if they did not necessarily meet the formal exercise guidelines. But, first, the researchers needed to establish a baseline of how many deaths might be related to too-little movement. So, they began gathering data from the ongoing National Health and Nutrition Examination Survey, or NHANES, which periodically asks a representative sample of the population about their lives and health. It also provides some of them with activity trackers, to objectively measure how much they move.The researchers now pulled information from 4,840 participants of different ethnicities, male and female, who ranged in age from 40 to 85. All had joined the survey between 2003 and 2006 and worn an activity monitor for a week. Based on that data, the researchers grouped people according to how many minutes they walked or otherwise moved most days. They also checked people’s names against a national death registry to establish mortality risks for the various activity levels.Using those results, they began creating a series of statistical what-if’s. Suppose, the researchers asked, everyone who was capable of exercising began exercising moderately, such as by walking briskly, for an extra 10 minutes per day, on top of how much or little they currently worked out? How many deaths might not happen?The researchers made adjustments to account statistically for those people who were too frail or otherwise unable to walk or easily move around. They also considered age, education, smoking status, diet, body mass index and other health factors in their calculations.Then, the researchers ran the same statistical scenario with everyone working out for an extra 20 minutes a day and, finally, for an extra 30 minutes a day and checked the mortality outcomes.Quite a few people would live longer in any of those scenarios, they found. According to the modeling, if every capable adult walked briskly or otherwise exercised for an additional 10 minutes a day, 111,174 deaths annually across the country — or about 7 percent of all deaths in a typical year — might be avoided.When they doubled the imagined exercise time to an extra 20 minutes a day, the number of potentially averted deaths rose to 209,459. Tripling the exercise to 30 extra minutes a day averted 272,297 deaths, or almost 17 percent of typical annual totals. (The data was gathered before the pandemic, which has skewed mortality numbers.)Those figures might seem abstract, but, in practice, those hundreds of thousands of deaths forestalled could turn out to be deeply personal. They could mean avoiding the early death of a spouse, parent, friend, grown child, co-worker or, of course, us, said Pedro Saint-Maurice, an epidemiologist at the National Cancer Institute, who led the new study. “There is a message in this data for public health entities” about the importance of promoting physical activity to reduce premature deaths, he said. And the message applies equally to each of us.So get up and walk or engage in some kind of moderate physical activity for an extra 10 minutes today. Invite your friends, colleagues and aging parents to do the same. “In this context, a little additional physical activity can have a huge impact,” Dr. Saint-Maurice said.

Cross-country ski racers were less likely to develop anxiety disorders. The good news is less intense aerobic activities may provide similar benefits.To better cope with all the dispiriting news this winter about rising Covid-19 cases and so much else, you might want to get out and play in the snow, according to a new report. The large-scale study of almost 200,000 cross-country skiers found that being physically active halves the risk of developing clinical anxiety over time. The study, from Sweden, focused on skiing, but the researchers said almost any kind of aerobic activity likely helps protect us against excessive worry and dread, a cheering thought as we face yet another grim pandemic season.Science already offers plenty of encouraging evidence that exercise can lift our moods. Experiments show that when people (and lab animals) start working out, they typically grow calmer, more resilient, happier and less apt to feel unduly sad, nervous or angry than before. Epidemiological studies, which often focus on the links between one type of activity or behavior and various aspects of health or longevity, likewise find that more exercise is linked with substantially lower chances of developing severe depression; conversely, being sedentary increases the risk for depression. A remarkable neurological study from 2013 even found that exercise leads to reductions in twitchy, rodent anxiety, by prompting an increase in the production of specialized neurons that release a chemical that soothes over-activity in other parts of the brain.But most of these studies were small, short term or mainly relevant to mice, leaving open many questions about what kinds of exercise might help our mental health, how long mood enhancements might potentially last, whether men and women benefit equally and whether it is possible to work out too much and perhaps increase your likelihood of feeling emotionally worse off.So, for the new study, which was published in Frontiers in Psychiatry, exercise scientists at Lund University in Sweden and other institutions decided it would be worthwhile to look into the long-term mental health of the thousands upon thousands of men and women who have raced Sweden’s famous Vasaloppet cross-country skiing event over the years.The Vasaloppet, which celebrates its centenary this winter, is the largest series of cross-country ski races in the world, with crowds of racers annually lining up in the woods of central Sweden to whoosh, glide and pant through races ranging in length from 30 kilometers, or almost 19 miles, to the showcase distance of 90K, about 56 miles. Because this kind of endurance event requires abundant health, stamina and training, researchers previously have used data about Vasaloppet racers to study how exercise influences heart health, cancer risks and longevity.“We use participation in a Vasaloppet as a proxy for a physically active and healthy lifestyle,” said Tomas Deierborg, the director of the experimental medicine department at Lund University and senior author of the new study, who has twice completed the 90K race.To start, he and his colleagues gathered finishing times and other information for 197,685 Swedish men and women who participated in one of the races between 1989 and 2010. They then crosschecked this information with data from a Swedish national registry of patients, looking for diagnoses of clinical anxiety disorder among the racers in the following 10 to 20 years. For comparison, they also checked anxiety diagnoses during the same time period for 197,684 of their randomly selected fellow citizens who had not participated in the race and were generally considered relatively inactive.The skiers, the researchers found, proved to be considerably calmer over the decades after their race than the other Swedes, with more than 50 percent less risk of developing clinical anxiety. These good spirits tended to prevail among male and female skiers of almost any age — except, interestingly, the fastest female racers. The top female finishers from each year tended to be more likely afterward to develop anxiety disorders than other racers, although their risk overall remained lower than for women of the same age in the control group.These results indicate “the link between exercise and reduced anxiety is strong,” said Dr. Lena Brundin, a lead investigator of neurodegenerative diseases at the Van Andel Research Institute in Grand Rapids, Minn., who was another author on the study.And helpfully, you probably don’t need to cross-country ski for long distances in the snowy woods of Sweden to reap the rewards, Dr. Deierborg said. Earlier studies of exercise and mood suggest that following the World Health Organization’s recommendations of about 30 minutes of brisk walking or similar activities most days “has good effects on your mental health,” he said, and these benefits appear to apply to a “broader population” than just Swedes.Still, it may be worthwhile to monitor your psychological response to intense training and competition, especially if you are a competitive woman, he said. The finding that the fastest women tended to develop anxiety more often than other racers surprised the researchers, he said, and suggests perhaps performance anxiety or other issues could be initiated or exacerbated in some people by racing.“It is not necessary to complete extreme exercise to achieve the beneficial effects on anxiety,” Dr. Brundin said.The findings have limitations, though. They cannot prove exercise causes people to enjoy better moods, only that highly active people tend to be less anxious than their more sedentary peers. The study also does not explain how skiing might reduce anxiety levels. The researchers suspect physical activity changes levels of brain chemicals related to mood, such as dopamine and serotonin, and reduces inflammation throughout the body and brain, contributing physiologically to stouter mental health. Getting outside among silent, snow-drenched pines and far from Zoom calls while training for a Vasaloppet probably does not hurt, either.Any exercise in any setting likely should help us cope better this winter, the researchers said. “A physically active lifestyle seems to have a strong effect on reducing the chances of developing an anxiety disorder,” said Dr. Deierborg, who hopes to extend those benefits to the next generation. He plans to enter and train for another Vasaloppet in a few years, he said, when his young children are old enough to join him.

Muscles develop a lasting molecular “memory” of past resistance exercises that helps them bounce back from long periods of inactivity.After two years of Covid-19 and its disruptions to our exercise routines, many of us may feel like we have forgotten how to be fit. But an encouraging new study suggests that our muscles remember. The study involved mice, but it builds on similar experiments with weight training and people. It found that muscles developed a pervasive and lasting molecular “memory” of past resistance exercises that helped them bounce back quickly from long layoffs.In the study, animals that completed a rodent form of resistance training developed changes in their muscles’ DNA that lingered long after they stopped exercising. The mice then packed on muscle mass much faster than other animals when they began training again. And as an encouraging side note to those who are taking up weight training for the first time, the findings also suggest that we should be able to build new muscle memories, regardless of our age.Until recently, the term “muscle memory” usually described our ability to bike, ski, throw to first base or repeat other common physical tasks, even if we had not pedaled, schussed or beelined a baseball in years. Our bodies remember how. But this type of memory, while real, is not really a muscle memory. These memories exist within motor neurons in our brains.But scientists knew that something happened within muscles themselves when they were worked hard, especially during weight training, and that these changes affected how muscles later responded to exercise. “Anecdotally, people say things like, ‘I used to be an athlete, then took time off, but my muscles came back as soon as I started’” lifting weights again, said Kevin Murach, a professor of health and human performance at the University of Arkansas, who oversaw the new study.Those stories piqued his and other researchers’ interest. How, they wondered, do muscles “remember” past workouts? And in what ways do those memories help muscles rebound after time away from the gym?Some preliminary studies with animals suggested that genes inside the nuclei of muscle cells worked differently after resistance exercises. Then, in 2018 and 2019, several much-discussed studies of people looked into the epigenetics of resistance training. Epigenetics refers to changes in the ways that genes operate, even though the gene itself does not change. It mostly involves a process called methylation, in which clusters of atoms, called methyl groups, attach themselves to the outside of genes like minuscule barnacles, making the genes more or less likely to turn on and produce particular proteins.In the recent human experiments, resistance exercise changed methylation patterns on a number of genes in people’s muscles, and those changes remained evident weeks or months later, even after the volunteers stopped exercising and lost some of their muscle mass. When they began lifting again, they packed muscle back on much faster than when the studies started, the researchers found. In essence, their muscles remembered how to grow.But those studies, while intriguing, lasted a few months at most. It was still unclear if exercise from much longer ago would linger as a genetic memory in our muscles, or just how many different cells and genes in muscles would be affected epigenetically by resistance training.So for the new study, which was published recently in Function, a flagship journal of the American Physiological Society, Dr. Murach and his colleagues, including the lead author Yuan Wen, decided to recreate the human weight-training experiments as closely as possible in adult mice. Rodents’ life spans are far more condensed compared with ours, meaning that changes seen in the animals after several months might appear in people after several years.But since mice cannot use barbells, the scientists had them run on weighted running wheels, which were designed to provide leg-muscle resistance training. The animals trained for eight weeks and then sat in their cages for 12 weeks — about 10 percent of their life spans, which would be years for us. The animals then trained again for a month, joined by mice of the same age that were new to the exercise and that served as controls. Throughout, the researchers biopsied and microscopically studied their muscles.They noted plenty of differences in gene methylation in muscle cells after the mice trained; most of the changes remained months after they stopped exercising. In general, these epigenetic changes dialed up the operation of genes involved in muscle growth while quieting gene activity elsewhere, making the genetic process of building muscle “more refined,” Dr. Murach said. Even after months of inactivity, these changes helped the trained mice add more muscle more quickly during retraining, compared with the mice that had not previously trained.Of course, this study involved mice, not people. It also looked only at resistance exercises and not at aerobic workouts.But since many of the genes the researchers tracked are the same ones that researchers studied in the human experiments, the findings most likely have relevance for any of us who hope to build up our muscles in 2022. They suggest that:No matter how long it has been since we’ve been to the gym or joined an online body-weight workout, our muscles should remain primed to respond to the exercises when we start working out again.It may never be too late to start laying down muscle memories, even if we have rarely or never lifted weights. The mice in the study were all adults when they began the weighted-wheel workouts, yet they all managed to build muscle memories that allowed them to bulk up faster after a period of inactivity. “It’s better to start sometime than not at all,” Dr. Murach said.

The most vital exercise science of 2021 provided a reminder that our bodies and minds can flourish, no matter our circumstances.In a year filled with Covid-related hopes, setbacks, advances and losses, the most vital exercise science of 2021 provided a reminder that for many of us, our bodies and minds can strengthen, endure and flourish, no matter our circumstances. If we move our bodies in the right ways, a growing body of evidence suggests we might live with greater stamina, purpose and cognitive clarity for many years to come. And it may not take much movement.In fact, some of the year’s biggest fitness news concerned how little exercise we might be able to get away with, while maintaining or even improving our health. A study from January, for instance, showed that just five minutes of intense calisthenics substantially improved college students’ aerobic fitness and leg strength. Another series of studies from the University of Texas found that four seconds — yes, seconds — of ferocious bicycle pedaling, repeated several times, was enough to raise adults’ strength and endurance, whatever their age or health when they started.Even people whose favorite workout is walking might need less than they think to reach an exercise sweet spot, other new research suggested. As I wrote in July, the familiar goal of 10,000 daily steps, deeply embedded in our activity trackers and collective consciousness, has little scientific validity. It is a myth that grew out of a marketing accident, and a study published this summer further debunked it, finding that people who took between 7,000 and 8,000 steps a day, or a little more than three miles, generally lived longer than those strolling less or accumulating more than 10,000 steps. So keep moving, but there’s no need to fret if your total doesn’t reach a five-figure step count.Of course, exercise science weighed in on other resonant topics this year, too, including weight. And the news there was not all cheering. Multiple studies this year reinforced an emerging scientific consensus that our bodies compensate for some of the calories we expend during physical activity, by shunting energy away from certain cellular processes or prompting us unconsciously to move and fidget less. A study from July, for example, that examined the metabolisms of almost 2,000 people concluded that we probably compensate, on average, for about a quarter of the calories we burn with exercise. As a result, on days we exercise, we wind up burning far fewer total calories than we might think, making weight loss that much more challenging.On the other hand, exercise seems essential for weight maintenance, according to other research this year. A new scientific analysis of participants from the TV weight-loss contest “The Biggest Loser” found that those who exercised the most in the years after the program ended were the least likely to have regained all of the pounds they shed during the show.Exercise also has a disproportionate impact on our odds of enjoying a long, healthy life. According to one of the most inspiring studies this year, overweight people who started working out lowered their risk of premature death by about 30 percent even if they remained overweight, with exercise providing about twice as much benefit as weight loss might.Exercise enhances our brain power, too, according to other, memorable experiments from this year. They showed physical activity fortifying immune cells that help protect us against dementia; prompting the release of a hormone that improves neuron health and the ability to think (in mice); shoring up the fabric of our brains’ white matter, the stuff that connects and protects our working brain cells; and likely even adding to our creativity. In a nifty study from February, physically active people tended to dream up more-inventive ways to use car tires and umbrellas, a standard test of creativity, than people who seldom moved around much. Taken together, this year’s exercise neuroscience research makes “a strong case for getting up and moving” if we hope to use our brains with ongoing clarity and in imaginative ways deep into our golden years, as one of the researchers said to me.Still, the study that stuck with me most this year had less to do with the myriad ways exercise remodels our bodies and brains and more with how it might shape our sense of what matters. In the study, which I wrote about in May, active people reported a stronger sense of purpose in their lives than inactive people. “A sense of purpose is the feeling you get from having goals and plans that give direction and meaning to life,” the study’s lead researcher told me. “It is about being engaged with life in productive ways.” The study found that exercise amplified people’s purposefulness over time, while simultaneously, a sturdy sense of purpose fortified people’s willingness to exercise. In effect, the more people felt their lives had meaning, the more they wound up moving, and the more they moved, the more meaningful they found their lives.It’s a result worth remembering as we look ahead with wary optimism. So stay healthy, active and in touch in 2022, everyone. Here’s to a happy new year!

People who are aerobically fit and work out a lot tend to imbibe more than their less fit peers.People who work out regularly and are aerobically fit tend to guzzle a surprising amount of alcohol, according to a new study, well timed for the holidays, of the interplay between fitness, exercise and imbibing. The study, which involved more than 40,000 American adults, finds that active, physically fit men and women are more than twice as likely to be moderate or heavy drinkers as people who are out of shape. The results add to mounting evidence from previous studies — and many of our bar tabs — that exercise and alcohol frequently go hand in hand, with implications for the health effects of each.Many people, and some researchers, might be surprised to learn how much physically active people tend to drink. In general, people who take up one healthy habit, such as working out, tend to practice other salubrious habits, a phenomenon known as habit clustering. Fit, active people seldom smoke, for instance, and tend to eat healthful diets. So, it might seem logical that people who often exercise would drink alcohol sparingly.But multiple studies in recent years have found close ties between working out and tippling. In one of the earliest, from 2001, researchers used survey answers from American men and women to conclude that moderate drinkers, defined in that study as people who finished off about a drink a day, were twice as likely as those who didn’t drink at all to exercise regularly. Later studies found similar patterns among college athletes, who drank substantially more than other collegians, a population not famous for its temperance.In another revealing study, from 2015, 150 adults kept online diaries about when and how much they exercised and consumed alcohol for three weeks. The results showed that on the days they exercised the most, they also tended to drink the most afterward.But these and other past studies, while consistently linking more physical activity and more drinking, tended to be small or centered on the young, or relied on somewhat casual reports of what people told researchers about their workouts and alcohol intake, which can be notoriously unreliable.So, for the new study, titled “Fit and Tipsy?” and recently published in the journal Medicine & Science in Sports & Exercise, researchers with The Cooper Institute in Dallas and other institutions turned to more objective data about tens of thousands of American adults. All were part of the large and ongoing Cooper Center Longitudinal Study, which looks at cardiovascular health and its relationship to various behavioral factors and other medical conditions.Study participants visited the Cooper Clinic in Texas for annual checkups and, as part of those exams, completed treadmill tests of their aerobic fitness. They also completed extensive questionnaires about their exercise and drinking habits and whether they worried about their alcohol intake. The researchers gathered records for 38,653 participants who were of legal age and reported drinking at least once a week. (The authors left teetotalers out of the study mix, because they wanted to compare light drinkers to heavier drinkers.) Then they ran numbers.As in earlier studies, the fitter people were, the more they tended to drink. The fittest women were about twice as likely to be moderate drinkers as women with low aerobic capacities. Moderate drinking meant the women drank between four and seven glasses of beer, wine or spirits in a typical week. The fittest men were more than twice as likely to be moderate drinkers — up to 14 drinks per week — than men who were less fit. The researchers considered people’s reported exercise habits and adjusted for age and other factors that could have influenced the results, and the odds remained consistently higher.Fit men and some women also had a slightly higher likelihood of being heavy drinkers — defined as having eight or more weekly drinks for women and 15 or more for men — than their less fit peers. Interestingly, fit women who were heavy drinkers often reported concerns about their level of alcohol intake, while fit men in that category rarely did.What might these results mean for those of us who work out regularly to try to stay in shape? While they clearly show that fitness and increased drinking go hand-in-hand, “most people probably don’t associate physical activity and alcohol intake as linked behaviors,” said Kerem Shuval, the executive director of epidemiology at the Cooper Institute, who led the new study. So, people who exercise should be aware of their alcohol intake, he said, even tracking how often they imbibe each week.Doctors and scientists cannot say with certainty how many drinks might be too many for our health and well-being, and the total likely differs for each of us. But talk to your doctor or a counselor if your drinking worries you (or worries your spouse or friends or training partners).Of course, this study has limits. It mostly involved affluent, white Americans, and it showed only an association between fitness and alcohol intake and not that one causes the other. It also cannot tell us why working up a sweat might lead to excess boozing, or vice versa.“There probably are social aspects,” Dr. Shuval said, with teammates and training groups bonding over beers or margaritas after a competition or workout. Many of us likely also put a health halo around our exercise, making us feel our physical exertions justify an extra cocktail — or three. And, intriguingly, some animal studies show that both exercise and alcohol light up parts of the brain related to reward processing, suggesting that while each, on its own, can be pleasurable, doing both might be doubly enticing.“We need a lot more research” into the reasons for the relationship. Dr. Shuval said. But for now, it is worth keeping in mind, especially at this festive time of year, that our running or cycling outings or trips to the gym could influence how often, and how enthusiastically, we toast the new year.