Accumulated evidence suggests that sitting for prolonged periods of time increases risk for heart disease, diabetes, cancer, and death, regardless of whether a person exercises regularly or not. The article is published in Annals of Internal Medicine.
More than one half of the average person's waking life involves sedentary activity, such as watching television, working at a computer, or commuting. Studies have explored the independent association between prolonged sitting and health outcomes after adjusting for physical activity; however, the magnitude, consistency, and manner of association between sedentary time and outcomes independent of physical activity remain unclear.
Researchers conducted a systematic review and meta-analysis of published research to quantitatively evaluate the association between sedentary time and health outcomes independent of physical activity participation among adults. The evidence shows that prolonged sitting is independently associated with negative health outcomes and mortality. However, the deleterious effects of sitting time on health are more pronounced among those who do little or no exercise than among those who exercise regularly.
Tips from the author on reducing sedentary time
Study author, David Alter, MD, PhD, Senior Scientist at Toronto Rehabilitation Institute-University Health Network and Institute for Clinical Evaluative Sciences, says that exercising one hour per day should not give us the right of passage or peace of mind to remain seated for the remaining 23. He offers simple strategies for becoming less sedentary, such as taking a 1-3 minute break every half hour or so throughout the day to stand (standing burns twice as many calories as sitting) or move around at work. Standing or exercising while watching television can also help. He tells his patients to set achievable goals and scale up slowly. For example, start by reducing sitting times by 15-20 minutes per day and set weekly goals to improve from there. Over time, one should aim for 2-3 fewer sedentary hours in a 12 hour day.