Publisher Health

Sitting for hours at a desk can play havoc with our metabolic health, contributing over time to high blood sugar and high cholesterol, even in people who otherwise seem mostly healthy. But a practical though small new study shows that standing up and moving every 30 minutes for about three minutes may lessen the health impacts of over-sitting. The study found that climbing several flights of stairs, bopping through some jumping jacks or squats or even taking as few as 15 steps during these mini-breaks improved aspects of blood sugar control among office workers, without noticeably interrupting their work flow.

But the study, which involved 16 middle-aged, white-collar workers at high risk for Type 2 diabetes, also indicates that these bi-hourly, three-minute breaks likely represent the minimum amount of movement needed to protect metabolic health. While 15 steps twice an hour may be a good start, they should not be the only steps we take toward reducing how much we sit.

For most of us, sitting is not just commonplace but constant. According to epidemiological studies, adults in the United States typically sit for about six and a half hours a day, with most of that time uninterrupted by standing or strolling. This postural lassitude likely accelerated during the pandemic. Preliminary data suggests that many of us are more inactive now than in 2019, especially if we have children and jobs.

Such relentless sitting squashes metabolic health. Or, as the new study’s authors write, “Every waking hour spent in sedentary postures (that is, sitting or lying) increases risk for metabolic syndrome and Type 2 diabetes.” Blame flaccid muscles. When we sit, the muscles in our legs, which are the largest in our body and are usually active and hungry, barely contract, so, require minimal fuel and slurp little sugar from our bloodstreams. They also do not release biochemical substances that would normally help break down fatty acids in the blood. So, when we hunch over our desks, blood sugar and cholesterol build up in our bloodstreams.

Helpfully, frequent breaks from sitting improve blood sugar control and cholesterol levels, past studies show. But much of that research took place in university labs and lasted only a day or two, conditions that do not reflect real life.

So, for the new study, which was published last month in The American Journal of Physiology: Endocrinology and Metabolism, an international consortium of scientists, led by researchers at the Karolinska Institute in Stockholm, Sweden, decided to see what would happen if office workers agreed to break up their sitting time, over three weeks, in their normal workplace.

They began by recruiting 16 middle-aged men and women in Stockholm with sedentary desk jobs and a history of obesity, putting them at high risk for metabolic problems like diabetes. They checked the volunteers’ current metabolic health and asked them to wear activity monitors for a week, to get baseline numbers.

Then, half of the volunteers continued with their normal lives, as a control, and the rest downloaded a smartphone app that alerted them every 30 minutes during the workday to rise and be active for three minutes. They ambled halls, strolled stairs, marched in place, squatted, hopped or otherwise moseyed about in whatever way they found convenient, tolerable and not overly distracting or amusing to their co-workers. But they had to take a minimum of 15 steps before the app recorded their movement as an activity break.

The experiment continued for three weeks, after which everyone returned to the lab for another round of metabolic tests. The researchers found that the two groups’ results subtly diverged. The control group displayed ongoing problems with insulin resistance, blood sugar control and cholesterol levels. But the other volunteers, who had stood and moved while at work, showed lower fasting blood sugar levels in the morning, meaning their bodies better controlled blood sugar during the night, a potentially important indicator of metabolic health. Their blood sugar also stabilized during the day, with fewer spikes and dips than in the control group, and the amount of beneficial HDL cholesterol in their bloodstreams rose. These improvements were slight, but might mean the difference, over time, between progressing to full-blown Type 2 diabetes or not.

Interestingly, the gains also ranged, depending on how often and how rigorously workers complied with their app alerts. Those who rose regularly and were the most active — generally managing 75 steps or more during the three minutes — improved their metabolisms the most. Others, accumulating fewer steps, or frequently ignoring their beeping alerts, benefited less.

But their metabolic health did improve somewhat, said Dr. Erik Näslund, a professor at the Karolinska Institute who oversaw the new study. The findings suggest that aiming to get up twice an hour is worthwhile, even if we do not always succeed. He offered two pieces of advice to anyone concerned about over-sitting and their metabolic health.

• Download an app or set an alarm on your computer or phone to remind you to rise every half-hour. Walk for a few minutes. Jog in place. “Going to the bathroom or getting a coffee” also count, Dr. Naslund said, with the second potentially contributing to the first.

• Be sure to keep moving, outside of work hours. “In general, it is important to introduce more physical activity into our lives,” he said. “Walk stairs rather than take the elevator. Get off one bus stop earlier on the way home. There are so many minor changes we can make that are beneficial for metabolic health.”