Too Much Sitting Can Be Deadly, Even if You Exercise

Lisa Franchi January 23, 2015

Exercising regularly doesn’t spare you from the serious health risks associated with sitting too much, suggests a new study.

In the study review by Canadian researchers, it was found that prolonged daily sitting was linked to significantly higher odds of heart disease, diabetes, cancer and dying. And even if study participants exercised regularly, the accumulated evidence still showed worse health outcomes for those who sat for long periods, the researchers said. However, those who did little or no exercise faced even higher health risks.

Among the studies reviewed by Biswas and his team, the definition of prolonged sitting ranged from eight hours a day to 12 hours or more. Sitting, or sedentary activities ubiquitous with sitting such as driving, using the computer or watching TV, shouldn’t comprise more than four to five hours of a person’s day, Biswas said, citing guidelines issued by Public Health Agency of Canada.

"We found that exercise is very good, but it’s what we do across our day," he said. "Exercise is just one hour in our day, if we’re diligent; we need to do something when we’re not otherwise exercising, like finding excuses to move around, take the stairs, or carry groceries rather than use the [shopping cart] at the supermarket."

The biggest health hazard stemming from prolonged sitting, according to the review, was a 90 percent higher risk of developing type 2 diabetes. Among studies examining cancer incidence and deaths, significant links were specifically noted between sedentary behaviour and breast, colon, uterine and ovarian cancers.

"The idea that we could exercise for 15 or 20 minutes a day and that could completely erase any harms of a sedentary lifestyle for the other 23 hours a day is just too hopeful," Septimus noted. "This showed us that yes, there is some benefit to physical activity . . . but it’s not enough."

To cut the health risks associated with sitting, the researchers recommend taking a one- to three-minute break every half-hour during the day to stand (which burns twice as many calories as sitting) or walking around; standing or exercising while watching TV, gradually reducing daily sitting time by 15 to 20 minutes per day; and aiming for two to three fewer sedentary hours over a 12-hour day.

The study was published in the journal Annals of Internal Medicine.

Source of this article: Risk for Disease Incidence, Mortality, and Hospitalization in Adults: A Systematic Review and Meta-analysis