Breaking up prolonged sitting with regular activity snacks can help preserve muscle mass, study says

Breaking up prolonged sitting with regular activity snacks can help preserve muscle mass, study says

Breaking up prolonged sitting with regular activity "snacks" can help maintain muscle mass and quality, according to a new study from researchers at the University of Toronto.

Daniel Moore, an associate professor of muscle physiology in the Faculty of Kinesiology and Physical Education (KPE), who led the study, found that short bouts of activity, such as two minutes of walking or bodyweight squats, allow the body to use more amino acids from meals to build muscle proteins.

The research results were recently published in the Journal of Applied Physiology.

“We know that prolonged periods of sedentary behavior impair the body's ability to filter sugar from the blood after a meal,” says Moore, who directs the Iovate/Muscletech Metabolism & Sports Science Lab at KPE.

"However, breaking up this sedentary phase with short bouts of activity, such as two minutes of moderate-intensity walking or getting up and down from a chair (i.e. bodyweight squats) 15 times, can improve the way our bodies remove sugar from our meals."

In this case, researchers wanted to understand whether breaking up extended periods of sitting, common in many workplaces, increases our muscles' ability to use the protein building blocks, called amino acids, from food to help them repair or replace old or damaged proteins.

"This is critical to ensuring that the body has an adequate amount and quality of muscle," says Moore, who co-authored the study with KPE's Eric Williamson, a recent graduate student, Nathan Hodson, a postdoctoral student, Stephanie Estafanos, PhD student, Michael Mazzulla, a graduate student, Jenna Gillen, Assistant Professor of Exercise Physiology, and Dinesh Kumbhare, Scientist at the Toronto Rehabilitation Institute, University Health Network, and Associate Professor at the Temerty Faculty of Medicine.

They examined 12 people (seven men, five women) in three studies for seven and a half hours each. Participants were exposed to prolonged sitting, broken up every 30 minutes by short periods of walking or bodyweight squats. The activity helped improve the efficiency of dietary amino acids used for muscle protein synthesis - the process of repairing or replacing old or damaged proteins.

This is significant because prolonged periods of low muscle activity—from sitting, wearing a cast, or bed rest—are associated with loss of muscle mass that occurs parallel to or due to an inability of our muscles to build new proteins after we eat a protein-containing meal.”

Daniel Moore, Associate Professor of Muscle Physiology, Faculty of Kinesiology and Physical Education (KPE)

"Our results highlight the importance of breaking up prolonged periods of sedentary time with short activity snacks. We believe they also highlight that exercise after eating can improve our diet and could allow more dietary amino acids from smaller meals or lower quality protein types to be used more efficiently."

The study was supported by the Natural Sciences and Engineering Research Council of Canada and the American College of Sports Medicine, among others.

Source:

University of Toronto

Reference:

Moore, DR, et al. (2022) “Activity snacks” while walking or bodyweight squatting increase the use of dietary amino acids for myofibrillar protein synthesis during prolonged sitting. Journal of Applied Physiology. doi.org/10.1152/japplphysiol.00106.2022.

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