Those who engage in regular physical activity but still spend a large proportion of their day in sedentary activity were found, on average, to be 30% less likely to die of any cause in a given period than were those who get little to no exercise. But even those who punctuate a long day of sitting with a vigorous workout were estimated to be 16% more likely to die of any cause in a given time than were those who do not sit for long.
The studies that formed the basis for such aggregations defined prolonged sitting, as well as high levels of physical activity, quite differently. While one study included participants who spent as little as an hour a day seated, the rest defined prolonged sitting as those who watched television for at least five hours a day on up to those who had more than six and, in one study, more than 11 hours of “sitting time” a day.
Any way you read it, these studies probably sweep most of us into the long-sitting category, since researchers estimate that more than half of the average American’s waking life is spent sitting.