Frequency vs Duration of Standing: How Does Each Affect Metabolism?

A new study found that the number of interruptions in the time spent sitting influenced metabolic responses, regardless of the length of time spent sitting or standing.

Researchers examined the effects of time spent sitting or standing on the metabolic process of 10 men, 33 ± 13 yr, with low levels of habitual exercise, with a body mass index of 28.3 ± 2.8 kg·m−2, and with a waist circumference of 100.2 ± 9.5 cm [mean ± SD].
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In the study, participants fasted for 12 hours before the trial, consumed a test breakfast and lunch at the facility, and had exhaled air and blood samples taken to measure energy expenditure, insulin, triglyceride, and glucose levels after meals. Participants completed 8 hours of uninterrupted sitting, 8 hours of prolong standing, where they stood still for 15 minutes every 30 minutes, and 8 hours of intermittent standing, where they stood for 1.5 minutes, 10 times every 30 minutes.

Their findings showed that during the intermittent standing, participants expended 296 ± 78 kJ more energy than the prolonged standing trial, and 617 ± 76 kJ more energy than uninterrupted sitting. During the prolonged standing trial, participants expended 320 ± 62 kJ more energy than uninterrupted sitting. There were no significant differences found in the glucose, insulin, or triglyceride responses between the trials.

According to their findings, intermittent standing expended the most energy, approximately 2 KJ, due to the muscular contractions between sit-to-stand transitions. Their study included 20 sit-to-stand transitions cycles per hour, which could be modified for real world scenarios to reduce long sedentary periods.

“For example, performing 4 sit-to-stand transition cycles per hour (ie, standing then sitting once every 15 min) over the course of the waking day would lead to approximately 100–120 kJ of additional daily energy expenditure over and above the increment in metabolic rate elicited by standing per se,” the researchers stated.

"The main finding of the this study is that increasing the frequency of breaks in sedentary time, while keeping total sedentary time constant, increased energy expenditure and fat oxidation over an 8-hour postprandial observation period. This is the first time that an independent effect of the number of sedentary breaks on day-long metabolic responses has been demonstrated, and these findings provide an explanation for the association between frequency of sedentary breaks and adiposity observed in the epidemiological data."

However, activities with greater intensity are needed to influence triglyceride, glucose, and insulin responses, they noted.

—Melissa Weiss

Reference:

Hawari N, Al-Shayji I, Wilson J, Gill J. Frequency of breaks in sedentary time and postprandial metabolic responses [published online December 2016]. Medicine & Science in Sports & Exercise. doi:10.1249/MSS.0000000000001034.