By replacing just 30 minutes of sedentary behaviors with moderate-to-vigorous physical activity or sleep, adolescents can lower their insulin resistance, a key factor in preventing Type 2 diabetes, according to preliminary research presented at the American Heart Association’s EPI-Lifestyle Scientific Sessions 2026. The meeting took place in Boston from March 17 to 20, 2026, offering epidemiological science on prevention, lifestyle and cardiometabolic health.
“I was happily surprised with the strength of the association of replacing 30 minutes of sedentary time with moderate-to-vigorous physical activity—a 15% lower insulin resistance is quite a big change,” said Soren Harnois-Leblanc, Ph.D., R.D., lead author of the study and a postdoctoral researcher in the department of population medicine at the Harvard Pilgrim Health Care Institute and Harvard Medical School, both in Boston. “Our findings mean that switching from sedentary behaviors to moderate-to-vigorous physical activity or sleep, even if it is only a few minutes per day to start, was beneficial for health.”
To assess the impact of typical daily activities on the development of insulin resistance in teenagers, investigators examined health data from Project Viva, an ongoing health study of children born between 1999 and 2002 and their mothers. Insulin resistance was measured using Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), a test that estimates insulin resistance based on fasting blood glucose and insulin levels. In early adolescence, at an average of nearly 13 years old, 802 participants kept sleep logs and wore an accelerometer (a sensor that quantifies movement accelerations, from which researchers can derive the intensity and duration of physical activity) constantly for 7 to 10 days, providing a breakdown of the movement activities they engaged in over a typical 24 hours.
By far, the highest percentage of daily time, 48% or 11.5 hours per day, was spent in sedentary activities. Examples of sedentary time may include sitting in class, doing homework, commuting and downtime in the evening, which often comes with screen time on an electronic device or watching TV.
Other daily activities, reported over a 24-hour period, included sleep (33%), low-intensity physical activity (such as casual walking, 17%), and moderate-vigorous physical activity (such as running, swimming or playing basketball, 2%).
The researchers then calculated how much a shift of just 30 minutes from sedentary activity to various types of physical activity or sleep could have impacted estimated insulin resistance levels in 394 of the study participants.
Among the study findings:
- Adolescents who replaced 30 minutes of sedentary time with moderate-vigorous physical activity could lower a measurement of insulin resistance, or lowering their HOMA IR score, by nearly 15%.
- Participants who exchanged 30 minutes of sedentary time with sleep could lower insulin resistance by nearly 5%.
- Shifting 30 minutes of sedentary time to low-intensity physical activity did not have a significant change in insulin resistance levels.
“This study shows that young adolescents spend a lot of their day being sedentary and only a small amount of time being physically active,” said Kershaw Patel, M.D., an American Heart Association volunteer and chair elect of the Association’s Council on Epidemiology and Prevention. “Interestingly, teens who had more moderate to vigorous physical activity early in adolescence showed signs of lower insulin resistance later on. The big takeaway is being active early in life can really make a difference for long‑term health.” Patel, who was not involved in this study, is an assistant professor of cardiology at Houston Methodist Hospital’s DeBakey Heart & Vascular Institute in Houston.
The American Heart Association’s Life’s Essential 8 metrics for optimal cardiovascular health includes strategies for incorporating healthy lifestyle into daily life. For example, dimming lights before bedtime, creating a nighttime routine that doesn’t include electronic devices with screens and putting the phone on “do not disturb” (or leaving it outside the bedroom while sleeping) can help to improve quality and quantity of sleep. Integrating physical activities with social time with friends, to clear your mind or reduce stress can make hikes or other exercise more appealing than sedentary activities.
While the study did not find an association between more time spent in light physical activity and lower insulin resistance, the investigators urge additional research on this topic.
“More time spent in light physical activity may be beneficial to prevent cardiometabolic disease in adults. Light physical activity is an interesting target because it is likely easier to integrate into everyday routines,” said Harnois-Leblanc.