A recent study gained a great deal of attention when it highlighted a seemingly contradictory correlation. Self-reported levels of physical activity increased at the same time as rates of obesity among a large sample of the American population. In other words, people were apparently more physically active but also getting fatter! This led many media reports to suggest that it doesn’t really matter what you weigh, but rather only that you’re “sufficiently” active. In short, a person can be both fit and fat.
I’m not about to argue that increased levels of physical activity are not beneficial. There are now hundreds, perhaps thousands, of studies that show being even moderately physically active is good for you and can contribute to greater overall fitness and health. I (along with every health expert on the planet) encourage everyone to increase their daily physical activity, and reap the many benefits.
My concern, however, is when these types of studies are used to support and gain greater acceptance for flawed and dangerous types of thinking about health and fitness. This latest study has a few major flaws: The first and most significant is that the documented levels of increased physical activity are self-reported by participants. Self-reported data are inaccurate, plain and simple. Of course, someone is going to tell you they’re healthy and active when you ask them! A social desirability bias exists when people respond or act in ways that they feel they’re expected to or are demanded by their larger social groups. We all know we should be physically active, but how many of us are actually doing it?
Unfortunately, the only real way to get good objective data on levels of physical activity are to strap accelerometers on people for days at a time to see how much they actually move. This is both cumbersome and expensive. It’s much easier just to ask them (and for them to lie about it).
Another issue I have with the study is their claim that Americans increased their levels of sufficient physical activity. That word “sufficient” is highly problematic. With levels of activity at an all-time low, what is now considered sufficient is much lower than in past years and decades. As a population, we have become so unhealthy and inactive that almost any amount of activity is now considered to be enough. These levels are most definitely much lower than what is actually needed for optimal health and fitness.
I won’t go on and on because I don’t really think this study is worth my, your or anyone’s time or attention. A final (and incredibly important) point that was sorely missed in the study is that any discussion on health and “a road map for action” cannot take place without any input or data on diet and nutrition. It would seem that if the population has indeed increased its activity levels and yet continues to gain weight, there is a massive gap on what role diet is playing in their overall health. Basic scientific laws suggest that mass cannot be created nor destroyed. If people are gaining weight, it means they are eating too much!
Running (and racing) continue to grow with increased levels of participants at many major events. Most people would argue that this is indeed and overwhelmingly a good thing (good for what and for whom is a completely different topic for another day).