Over the past several years, researchers have reported on the negative impacts of extended periods of sitting on health and mortality. Some have looked at whether exercise can mitigate any of those effects. The debate continues in a recent study.
Published in the American Journal of Physiology—Endocrinology and Metabolism (2016; 311 , E891–98), the study aimed to determine how prolonged sitting would affect the body’s response to triglycerides that enter the blood after a high-fat meal. Elevated triglyceride levels increase the risk for stroke, heart attack and heart disease. The study also looked at whether exercise reduced the effects of sitting.
Seven healthy men wore activity monitors throughout a three-pronged intervention. During one protocol, they spent 4 days being as active as possible—most of them logged around 17,000 steps and sat for approximately 8 hours each day. On the evening of the fourth day, they ran on a treadmill for an hour at 67% of VO2max and then ate a high-fat, high-sugar breakfast the following morning. A second intervention required them to sit for an average of 14 hours per day for 4 days. They repeated the treadmill run and breakfast protocol the next day. The third protocol mimicked the second intervention minus the treadmill workout.
According to the results, 2 days of prolonged sitting resulted in an increase in triglycerides, and after 4 days, the exercise bout had no impact on triglyceride levels. However, the active intervention led to a more positive outcome. The researchers suggested that, for optimal health, people should exercise regularly and sit as little as possible during the day.
“In conclusion, prolonged sitting over 2–4 days was sufficient to amplify [triglycerides], which was not attenuated by acute exercise, regardless of energy balance,” they added. “This underscores the importance of limiting sitting time even in people who have exercised.”