Most people would agree that physical activity is important to overall health. I certainly believe so as evidenced by my doctoral dissertation on physical activity. Yet, believing in something does not always translate to actual behavior... [insert uneasy pause] as evidenced by my inconsistent efforts at regular physical activity. At least I'm not alone! According to the President's Council on Fitness, Sports & Nutrition data:
Less than 5% of adults participate in 30 minutes of physical activity each day; only one in three adults receive the recommended amount of physical activity each week.
More than 80% of adults do not meet the guidelines for both aerobic and muscle-strengthening activities, and more than 80% of adolescents do not do enough aerobic physical activity to meet the guidelines for youth.
Children now spend more than seven and a half hours a day in front of a screen (e.g., TV, videogames, computer). Only one in three children are physically active every day.
28.0% of Americans, or 80.2 million people, aged six and older are physically inactive.
Is this the result of changing cultural norms and modern realities or are we evolutionary predisposed to being lazy? The nature vs. nurture debate is an ongoing one and applies to physical activity as well. Daniel Lieberman, an expert in human evolutionary biology, posed in a 2015 paper, “Is Exercise Really Medicine? An Evolutionary Perspective,” that it’s not our natural inclination to exercise for health alone. “It is natural and normal to be physically lazy,” he writes. “… I predict that hunter-gatherers in the Kalahari or the Amazon are just as likely as 21st century Americans to instinctually avoid unnecessary exertion. Although a small percentage of people today exercise as a form of medicine, doing their prescribed dose, the vast majority of people today behave just as their ancestors by exercising only when it is fun (as a form of play) or when necessary.”
So are we genetically programmed to think of exercise as "unnecessary exertion"? Lieberman explains that our ancestors struggled to amass enough food to make up for the calories they burned tracking down that food. So they needed to conserve their energy when they could.
But we don't have to conserve our energy today, right? Do we expend as much energy in sedentary jobs and long commutes? And we don't have to hunt for our food today! Well at least not in my suburban Chicago. Although my family did just get back from a weekend getaway of fishing and mushroom picking -- but that's another post and whatever we fished and gathered was not enough to sustain us for the weekend. Back to the point...Most modern humans don’t need to worry about whether after a hard workout they will be able to make up for the calorie deficit. Lieberman is quoted to have said in an interview “Our instincts are always to save energy. For most of human evolution that didn’t matter because if you wanted to put dinner on the table you had to work really hard... It's only recently, we have machines and technology to make our lives easier. … We’ve inherited these ancient instincts, but we’ve created this dream world and the result is inactivity.” He points to escalators in a mall or a subway station. When they are positioned near stairs, most people will choose the ones that move for them. This is often true for elevators in buildings as well. People will drive around a parking lot several times looking for the closest spot rather than park farther away and have to walk the relatively short distance.
Oh and it gets more complicated! There is now a lot of societal shame associated with not working out. Thus, going to the gym, or for a run, can often feel like a chore. “People are often made to feel bad [for not exercising] and I think that’s just as pernicious and wrong and irresponsible as shaming people for being overweight,” Lieberman said. "It’s not our fault that we are physically inactive, we live in a world that encourages that. They shouldn’t be made to feel bad. We need help..."
So, if you were physically active today when you didn't have to be, you may have overcome powerful evolutionary forces... or got help? If you didn’t, can you blame your ancestors?
p.s. thank you to a recent Washington Post article by Colby Itkowitz on this topic for inspiring me to blame my ancestors... and then to pat myself on the back for overcoming powerful evolutionary forces more than once a week over the past year!