Too Much Sitting Negates The Benefits Of Your Exercise

Picture by Carsten Knoch from Flickr

Since my earlier post on Runners Run A Lot, Also Sit A Lot, I've received quite a few questions on how much does sitting affect us. So here's a follow up post on that article.

Well, to answer your queries, according to research, each hour of sitting negates 8 % of your gain from an hour's worth of running. So if you ran an hour this morning and then sit for 10 hours after that during the day, you lose about 80% of the health benefit you gained from your morning run.

That's rather upsetting isn't it? I've never thought I had to subtract (any health benefit) from my exercise before. Fortunately for me, I don't sit much during the day when I'm treating my patients. I sit most when I'm reading doing research and writing articles for this blog.

Now for the not so good news. If you do an hour's worth of moderate intensity exercise (running is considered vigorous exercise), you lose about 16 % of your workout gains from each hour of sitting.

The above mentioned data were the same for both men and women.

Researchers obtained the results through analysis of objective fitness and exercise data obtained through the National Education and Nutrition Survey (NHANES). This is an annual survey conducted to assess the country's exercise and nutrition habits.

So for office workers and those who work from home and are mostly sitting, you should be walking up stairs rather than using the lifts, stand while talking on your phone, sitting on a gym ball, using a standing desk, walking out during your lunch and use a pedometer to log your dally step count.

As Little Eva (and later Kylie Minogue) sang, "So come on come on, do the loco-motion with me." 

Reference 

Kulinski JP, Khera A, Ayers CR et al (2014). Association Between Cardiorespiratory Fitness And Acclerometer-derived Physical Activity And Sedentary Time in General Population. Mayo Clinic Proceedings. DOI: http://dx.doi.org/10.1016/j.mayocp.2014.04.019. 

Surely I can sit now after all that walking ....

Picture by Julio Velasco from Flickr.

Runners Run A Lot, Also Sit A Lot

Potatoes picture from Flickr

You're very active. You may average between 30-40 miles (48-68 km) a week while training for your half or full marathon, running an average of an hour almost daily. You also sit a lot while not exercising or running, close to 8 hours hours or more a day at times. Does this sound like you? You may be what researchers term an "active couch potato."

A group of researchers studied runners (average age of the 218 runners was 35, slightly more than two-thirds were women) who competed in the Austin half and full marathon. These runners ran almost an hour a day (making them among America's most active adults). The runners sat a lot too, ranging from 8 to 11 hours daily.

While looking at the demographics of the runners, a large number of then tend to be professionals with office type desk bound jobs. Is that you?

There were big differences between workday and non workday activities for these runners. The runners slept seven hours a night in the work days and sat about 11.4 hours. While not working, they slept eight hours and sat about 8.5 hours.

There was no connection between training time and sitting time, meaning runners who ran more did not sit more or less than those who ran less. Their results suggest that the runners' sedentary behaviours did not displace their moderate to vigorous activities (running or other exercises). The two coexist at high levels in this study.

This study did not say that the runners' sitting time was unusually high or that it led to any health outcomes although other studies have shown that sitting time is an independent predictor for diabetes, high blood pressure, heart diseases and most other lifestyle diseases (Katzmaryzk et al 2009). In other words, excessive sitting may cancel out some of the benefits of your exercise.

These runners' are " simultaneously highly sedentary and highly active." The authors suggested that these runners' may be a good group for future studies. This may give us more information on how much we have to exercise to negate the harmful effects of sitting.

After spending all that time sitting, researching, reading and then typing this article, I'd better get up and stop sitting.

Reference

Whitefield G et al (2014). Sedentary And Active: Self-reported Sitting Time Among Marathon And Half-marathon Participants. J Phys Act Health. Jan 11(1): 165-172. doi: 10.1123/jpah.2011-0410.

While I was still actively training, once I came home after a hard swim, bike or run, I'll be sitting, eating or sleeping.....