By Jasminee Sahoye

Sitting for a long period could have adverse medical effects according to a study review by experts in Canada published in the Annals of Internal Medicine.

It says the amount of time a person sits during the day is associated with a higher risk of heart disease, diabetes, cancer, and death, regardless of regular exercise.

“More than one half of an average person’s day is spent being sedentary – sitting, watching television or working at a computer,” says Dr. David Alter, senior scientist, Toronto Rehab, University Health Network (UHN), and Institute for Clinical Evaluative Sciences.

“Our study finds that despite the health-enhancing benefits of physical activity, this alone may not be enough to reduce the risk for disease.”

The meta-analysis evaluated studies focused on sedentary behaviour. The lead author is Avi Biswas, PhD candidate, Toronto Rehab, UHN and the Institute of Health Policy, Management and Evaluation, University of Toronto, and the senior author is Alter, who is also associate professor of medicine, U of T.

They found the negative effects of sitting time on health, however, are more pronounced among those who do little or no exercise than among those who participate in higher amounts of exercise.

“The findings suggest that the health risk of sitting too much is less pronounced when physical activity is increased,” says Biswas. “We need further research to better understand how much physical activity is needed to offset the health risks associated with long sedentary time and optimize our health.”

Future research will help determine what interventions, in addition to physical activity, are effective against the health risk of sedentary time.

Alter says “avoiding sedentary time and getting regular exercise are both important for improving your health and survival. It is not good enough to exercise for 30 minutes a day and be sedentary for 23 and half hours.”

In the meantime, he emphasizes strategies people can use to reduce sitting time. The target is to decrease sedentary time by two to three hours in a 12-hour day.

“The first step is to monitor sitting times – once we start counting, we’re more likely to change our behaviour,” says Alter.

“Next is setting achievable goals and finding opportunities to incorporate greater physical activity – and less time sitting – into your daily life. For example, at work, stand up or move for one to three minutes every half hour; and when watching television, stand or exercise during commercials.”

A related study done in 2012 led by the University of Leicester, in association with colleagues at Loughborough University, discovered that sitting for long periods increases your risk of diabetes, heart disease and death.

That study, which combined the results of 18 studies and included a total of 794,577 participants, was led by Dr. Emma Wilmot, a research fellow in the Diabetes Research Group at the University of Leicester.

The research was in collaboration with colleagues from the newly established National Institute for Health Research (NIHR) Leicester-Loughborough Diet, Lifestyle and Physical Activity Biomedical Research Unit and was published in Diabetologia, the journal of the European Association of the Study of Diabetes.

The research showed those who sit for long periods have a higher chance in their risk of diabetes, heart-disease and death. Interestingly, the results were independent of any individual physical exercise undertaken, suggesting that even if an individual meets physical activity guidelines, their health may still be at risk if they sit for long periods.

Wilmot, a clinical research fellow in diabetes and endocrinology based at Leicester Diabetes Centre, Leicester General Hospital, said that on average an adult spends 50-70% of their time sitting.