New details have emerged from a study of marathoners and sitting time. The study showed that entrants in the Austin Marathon and Half Marathon (U.S.) trained roughly 65 kilometres a week and 48 kilometres a week respectively, for their races. That would make them very active adults. But they also do a lot of sitting: close to 12 hours a day at times.
Some researchers have begun using the seemingly paradoxical term “active couch potatoes” to describe such people.
“Considering the demographic make-up of marathon runners, we were not completely surprised by the high workday sitting,” co-author Geoffrey Whitfield, Ph.D., told Runner’s World. “These tend to be professionals with office-type jobs.”
It’s better to be an active couch potato than an all-in couch potato, but it’s not ideal. Other studies have shown that sitting time is an independent predictor for diabetes, high blood pressure, heart disease and most other “lifestyle diseases.” In other words, excessive sitting could cancel out some of the benefits of exercise.
The study looked into the weekday and weekend habits of 79 marathoners and 139 half marathoners. They had an average age of 35, and slightly more than two-thirds were women. To judge by their average body mass index, around 23.0, they were a trim, fit group.
The runners took a questionnaire on their sitting time two weeks before the marathon. In it, they estimated that they would finish the marathon in about 4:30, or the half marathon in about 2:15. They also reported on their various sedentary activities, such as sitting at work, watching TV/movies, talking/texting, etc.
The major activities showed big differences between workday and non-workday hours. During the week, the runners slept seven hours a night, and reported 11.4 hours of total sitting time. When not working, they slept an extra hour, and spent about 8.5 hours sitting.
There was no connection between training time and sitting time. That is, the runners who trained more didn’t sit any more or any less than those who trained less. “Our results suggest that sedentary behaviours do not displace moderate- to vigorous-intensity activities,” the study authors note. “The two co-exist at high levels in this sample.”
The authors believe their paper is the first to investigate sitting time among active endurance athletes. Still to be determined: Is there an amount of weekly endurance exercise that nullifies the harmful effects of sitting time?
“Given the state of the science, I’m not prepared to tell marathoners to sit less, especially after hard workouts!” says Whitfield. “Some new research suggests that associations between sedentary behaviour and many cardiovascular risk factors disappear after accounting for total physical activity participation.”
