Muscle inactivity behind the health risks of prolonged sitting even if you exercise

Over recent years, there has been considerable interest in the health hazards of prolonged sitting. However, it has been largely unknown what actually makes sitting so dangerous.

In this study, 150 healthy and physically active individuals wore special shorts which recorded their thigh muscle activities while they went about their normal daily life. The muscles were said to be inactive when the amplitude was less than what was measured during standing. In other words, already standing up was counted as activity. The investigators found out that even though the participants fulfilled the current exercise recommendations, their muscles were inactive for 65% of the time. People who had the least muscle activity had worse HDL cholesterol and triglyceride levels. However, already during standing the muscle activity was 200% higher than during sitting. The act of standing up to break up long periods of muscle inactivity might be beneficial for health – even if people exercise regularly.

View the study’s abstract

How does being sedentary negatively impact your health?

Multiple studies have reported that excessive sedentary behavior, or spending a great deal of your day sitting, is detrimental for your health. However, the physiology by which a sedentary behavior negatively impacts health is largely unknown and understudied. Recently, scientists with expertise in physical activity and exercise research came together to discuss what is known and unknown about the underlying physiological effects of sedentary time on health outcomes. The goal of this meeting was to make recommendations for future research. Conclusions from the meeting indicate that research should: 1) focus on the central and peripheral mechanisms that govern high or low sedentary behavior; 2) determining the physiological effects caused by a lack of movement rather than sitting per se; and 3) establishing new research strategies that can lead to better understanding of the mechanisms induced by chronic sedentary behavior.

View the study’s abstract