IRP Study Gets Kids Moving to Improve Blood Sugar Control

Interrupting Sedentary Time Could Help Stave Off Health Problems

By Brandon Levy

Tuesday, April 18, 2023

Many people don’t get much exercise these days, and kids are no exception. Whether at school, doing homework, or entertaining themselves online, children and teens spend hours on end sitting around. That lack of physical activity raises their risk for metabolic conditions like obesity and type 2 diabetes, but according to a recent IRP study, breaking up those long, sedentary periods with just a few minutes of exercise could yield noticeable benefits for their health.¹

Lifestyle factors like diet and physical activity have a large influence on health, including the chances of developing type 2 diabetes. Worryingly, between 2001 and 2017, the number of people under age 20 with the condition nearly doubled, and the COVID-19 pandemic has made the situation even more concerning.

Patients with type 2 diabetes are said to be ‘insulin-resistant’ because their cells are worse at using the hormone insulin to extract sugar, in the form of glucose, from their blood. This, in turn, results in elevated blood sugar levels that wreak havoc on the rest of the body. And although there are good treatments for type 2 diabetes in adults, the same can’t be said for younger people.

“That’s one of the motivating factors in my mind about trying to find preventive measures because once the cat is out of the bag for pediatric type 2 diabetes, treating the disease is very difficult,” explains Miranda Broadney, M.D., M.P.H., who led the new study while working as a staff clinician in the lab of IRP senior investigator Jack Yanovksi, M.D., Ph.D. “We don’t have good therapies to bring blood glucose levels back to a healthy state.”

One way to prevent or delay the development of type 2 diabetes is increasing physical activity, but many people of all ages dislike exercising and have trouble fitting it into their daily routines. Consequently, Dr. Broadney and Dr. Yanovksi wondered if periodically interrupting sedentary activities with much shorter periods of less strenuous movement could improve metabolic health.

In the new study, they put their theory to the test in two groups of healthy kids between the ages of 7 and 11, who visited the NIH Clinical Center for three-hour sessions on six consecutive days. During the research sessions, one group remained seated or lying down the entire time, while the other broke up that long sedentary stretch by walking on a treadmill at moderate speed for three minutes every half hour. While a prior study led by Dr. Broadney and Dr. Yanovski had examined the effects of this routine after just one session and found positive results,² the researchers did not know whether those benefits would only be temporary.

“Doing it a number of times in repetition allowed us to see if that improvement wears off over time or whether this is something that could lead to a sustained improvement if you just changed your habits and it became a new part of your lifestyle,” Dr. Broadney says.

“This experiment was really a model system to find out if we could modify how well children’s’ bodies use sugar by using very mild exercise of short duration that could be possible to use in the real world,” Dr. Yanovski adds. “It couldn’t be many hours in a row or so high-intensity that it would be impossible to implement in a classroom setting because it required a gym. It had to be something that someone might be able to do marching around their classroom.”

After the sixth and final day of the study, the researchers gave the kids a sweet drink and then analyzed samples of their blood taken several times over the next few hours. They found that the drink raised insulin levels significantly less in the group that interrupted sedentary time with physical activity, suggesting that their bodies required less insulin to fuel their cells with the sugar in the drink.

“Each person’s pancreas has a certain capacity to make insulin, and what actually causes high blood sugar to happen is when the pancreas is no longer able to make the amount of insulin required,” Dr. Yanovski explains. “That often happens after the pancreas has been working hard for quite a long time, but we know that the higher the demand, the greater the chances are that blood sugar will become a problem.”

“If you’re constantly firing all pistons and producing as much insulin as possible, you may burn out the pancreas, so if you can offload some of that demand, maybe you can preserve health,” Dr. Broadney adds.

Due to concerns that the kids might compensate for their increased physical activity during the study by eating more or being less active outside the research sessions, the IRP team supplied all the participants’ food during the experiment and asked the kids to wear activity trackers. These measures confirmed that the two groups of kids did not differ noticeably in how much they ate or how active they were in everyday life while participating in the study. In addition, the two groups of kids consumed roughly the same amount of food when they were given free access to a buffet after the blood test on their final day in the study.

All told, the experiment’s results suggest that breaking up the time kids spend being sedentary with short periods of physical activity could be a simple way to decrease their risk for metabolic ailments like type 2 diabetes. More studies will be needed to determine if such a regimen can noticeably improve the health of kids or adults who already have metabolic problems, but the ease of incorporating it into daily life, or even as part of the school day, make it a promising way to stave off those conditions in today’s increasingly inactive kids.

“You can add up very short bouts throughout the day and still get quite a good benefit in terms of health,” Dr. Yanvoski says. “To my mind, that makes it much more practical potentially that this could be carried out in a school with young kids. It’s hard to imagine teachers being able to enforce half an hour of high-intensity or even moderate-intensity physical activity, but you might be able to get kids to move for three or four minutes and then settle down.”

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References:

[1] Broadney MM, Belcher BR, Ghane N, Sheni R, Jayson MJ, Trenschel RW, Collins SM, Brychta RJ, Davis EK, Brady SM, Yang SB, Courville AB, Smith KP, Rosing DR, Chen KY, Yanovski JA. Effects of interrupting daily sedentary behavior on children's glucose metabolism: A 6-day randomized controlled trial. Pediatr Diabetes. 2022 Dec;23(8):1567-1578. doi: 10.1111/pedi.13430.

[2] Broadney MM, Belcher BR, Berrigan DA, Brychta RJ, Tigner IL, Shareef F, Papachrisopoulou A, Hattenbach JD, Davis EK, Brady SM, Berstein SB, Courville AB, Drinkard BE, Smith KP, Rosing DR, Wolters PL, Chen KY, Yanovski JA. Effects of Interrupting Sedentary Behavior With Short Bouts of Moderate Physical Activity on Glucose Tolerance in Children With Overweight and Obesity: A Randomized Crossover Trial. Diabetes Care. 2018 Oct;41(10):2220-2228. doi: 10.2337/dc18-0774.

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