Although dedicated runners are often confused and perhaps unhappy about the results of research regarding inactivity – ”What? I have to do more than run 8K every morning?’’ – the studies keep piling up.
Since then another new paper, this one from the Journal of Physical Activity & Health, has extended the findings in an important direction. It’s the first to look at the long-term effects of too-much sitting. It also measures the cardiorespiratory fitness versus sitting habits of 930 men who were followed for almost 10 years.
What were the results? Of the 930 male subjects, 124 developed metabolic syndrome in the followup period. Metabolic syndrome is shorthand for a collection of chronic conditions such as cardiovascular disease, diabetes, and high blood pressure. Even when you account for fitness level, those who did the most sitting were 1.65 times as likely to develop metabolic syndrome as those who did the least. (See table below.)
“Our research shows that regardless of your physical fitness – even if you have a high level of physical fitness – spending a large amount of time sitting puts you at an increased risk for developing metabolic syndrome,” lead author Anna E. Greer, Ph.D., told Runner’s World. “This is important because even those who exercise regularly still need to consider the amount of time they spend sitting.”
The study used data from the Cooper Clinic in Dallas, Texas, the source of many top exercise studies. Subjects in the Cooper studies often took treadmill tests, which provided an exact measure of their cardiorespiratory fitness. Such data is rare in other studies with large numbers of subjects.
This doesn’t mean that high fitness isn’t protective against such diseases. It is. The male subjects with the highest fitness had only about one-fourth the risk of developing metabolic syndrome as those in the low-fit group. So that 8K morning run still pays off. But you should also avoid sitting as much as possible, whether that’s at the office or home in front of the TV.
Like others in her field, Greer suggests that health-conscious individuals get out of their chairs whenever they can. Standing provides a modest relief, but a small burst of real movement like walking briskly for a few minutes or doing some push-ups is better. In her teaching at Greer gives students a “five-minute activity break” in the middle of any class that lasts longer than an hour.
“There are no official guidelines for exercise to overcome sedentary behavior,” Greer said. “However, many health professionals believe we should try to limit our discretionary sitting time – TV watching, video games, etc. – to two hours.”
TABLE: Among subjects with high cardiorespiratory fitness, those who spend more time sitting have a higher risk of developing metabolic syndrome
| TIME SITTING | RELATIVE RISK MetS |
| Low sitting | 1.00 |
| Moderate sitting | 1.51 |
| High sitting | 1.65 |
