Trends in Inactivity
The surveys reveal that, despite growing participation in a variety of physical activities (mostly in the form of episodical workouts), there are still no significant deviations from the historical trends of many modern diseases. Does this mean that the conventional approach to exercising is not effective in undoing the harm of chronic inactivity and sitting? Or is there, as I mentioned, another factor we need to consider?
I wouldn’t be so quick as to dismiss the possibility that we are becoming even more sedentary than ever. At the same time, however, we generally do work out more. So, how is it possible that we are more sedentary and more active at the same time? That might be the most important question we can ask.
It is becoming apparent that inactivity and sitting are independent risk factors of their own. The unused calories resulting from the absence of physical activity are just small pieces of a grand puzzle. It has been suggested that we treat sitting as a hazard, similar to smoking. If you smoke a pack of cigarettes every day, it doesn't matter how much fresh air you breathe in between your puffs. Similarly, it doesn't matter how much you exercise, as prolonged sitting will still take its toll on your body. In other words, if you sit – that's it!
From a serial cross-sectional study* with 51,896 participants, we found that – between 2007 and 2016 – the estimated total sitting time increased from 7.0 to 8.2 hours per day among adolescents and from 5.5 to 6.4 hours per day among adults.
You may or may not agree with these numbers. I personally find this study to be quite confusing. So do people, who commented on the article in Washington Post** that refers to this publication as the main data source for their discussion. But once again, we can only measure changes against earlier points in time. So, this study shows that the trend in the sedentary style prevalence is overall growing, no matter the demographics they chose for their research, so long as it remained comparably similar throughout the period of their study.
But if we were to talk strictly about the people who are sedentary due to their occupations, we can see a much more troublesome picture. If you consider the time people spend driving, casual socializing, dining, watching TV, and so on, a typical office worker spends over 10 hours - and some sources go as high as 15 hours - sitting each day. Which is twice the reported numbers for adults.
You have probably noticed that there has been a surge of workout programs emphasizing how little time you need to exercise. There are 20-minute, 10-minute, and even 5-minute high-intensity workouts. We choose quick, all-out sessions just so we can get back to sitting again. Ain’t that ironic?
* April 23/30, 2019 Trends in Sedentary Behavior Among the US Population, 2001-2016 - JAMA. 2019;321(16):1587-1597. doi:10.1001/jama.2019.3636; Lin Yang, PhD1,2,3,4; Chao Cao, MPH5; Elizabeth D. Kantor, MPH, PhD6; et al - https://jamanetwork.com/journals/jama/article-abstract/2731178