Sitting for long periods is widely known to be unhealthy, but new research from Swinburne suggests people may need to move sooner than previously thought. The findings, published in the journal npj Exercise Medicine and Health, indicate that sitting for more than 25 minutes at a time lowers muscle activity, which could lead to health problems.
The study was led by Dr Christian Brakenridge, a Swinburne researcher who studies everyday habits such as sitting, standing and sleeping. He said that breaking up long periods of sitting with exercise or walking keeps muscles more active while seated.
How researchers measured muscle activity during sitting
The team asked participants to wear special shorts fitted with sensors that tracked muscle activity in daily life. The data covered more than 7,000 sitting sessions.
Brakenridge said that when muscles are less active, blood flow and the uptake of blood sugar can drop. He said this may raise the risk of heart disease and type 2 diabetes.
Why the type of sitting makes a difference
According to the research, the way people sit matters. Activities such as driving, chatting with friends or working at a desk involve small muscle movements, making them less harmful than sitting still for hours to watch a film.
The researchers noted that small movements while sitting have been linked to better health outcomes, including lower body mass index, smaller waist circumference and reduced cardiovascular disease risk.
Breaking up sitting every 25 minutes
Brakenridge said that taking regular breaks from sitting is a simple way to reduce its negative effects. He gave the example of a total of 10 hours of sitting per day, where breaking it up with an activity every 25 minutes could add about 1.5 hours of increased muscle activity during sitting time.
He said this would correspond to a 10% reduction in muscle inactivity during waking hours, which earlier research linked to better health outcomes. He added that as more people spend time at screens, particularly in sedentary jobs, scheduling movement becomes increasingly important.
Small habits can also help. Brakenridge suggested that keeping a small glass of water nearby, so that you get up to refill it often, could have a major effect on everyday routines.
