It’s no secret that modern society often places a high value on physical fitness. Gym memberships, step-counting apps, and marathon training have become commonplace. But according to a renowned Harvard professor, our obsession with exercise might not be as “natural” as we think.
The Human Body Isn’t Built for Constant Exercise, But That’s Okay
Daniel E. Lieberman, an evolutionary biologist and professor at Harvard University, challenges the notion that a healthy lifestyle must include continuous physical exercise. In his book, “Exercised: Why Something We Never Evolved to Do Is Healthy and Rewarding,” Lieberman explores the idea that humans didn’t evolve to engage in prolonged periods of strenuous activity.
I recall a time when I tried to adopt an intense workout routine, only to find myself exhausted and unmotivated after a few weeks. Lieberman’s insights helped me understand that perhaps my body wasn’t designed for such constant exertion.
He doesn’t suggest we should abandon exercise altogether—far from it. Lieberman acknowledges the numerous health benefits of physical activity. However, he emphasizes that overexertion can be counterproductive. Instead of pushing ourselves to the brink, he advocates for moderation.
“Humans evolved to avoid unnecessary exertion,” Lieberman explains. Our ancestors were active out of necessity—hunting, gathering, and escaping predators—not because they sought out exercise for its own sake.
The Vital Functions That Drain Our Energy
One of the key points Lieberman makes is about our basal metabolic rate—the amount of energy our bodies use at rest to maintain vital functions like breathing, circulating blood, and regulating body temperature.
According to research cited by The National Institutes of Health (NIH), these basal activities consume about 60 to 75 percent of our daily energy expenditure. Surprisingly, the brain alone uses approximately 20 to 25 percent of this energy.
This means that even when we’re sitting quietly, our bodies are hard at work. Lieberman suggests that our natural inclination to conserve energy isn’t laziness—it’s an evolutionary trait designed to ensure survival.
I often felt guilty on days when I chose to relax instead of hitting the gym. Understanding that rest plays a crucial role in our overall energy balance has helped me embrace a more balanced approach to fitness.
Embracing Moderate and Natural Movement
Lieberman points out that while our ancestors did engage in physical activities like walking long distances to find food, they didn’t run marathons for fun. Walking is a natural movement for humans and is less taxing on the body than running.
He recommends simple practices to stay healthy without overdoing it. For example, aiming for about 7,000 steps a day—a goal supported by studies published in JAMA Network Open—can provide significant health benefits without the need for extreme workouts.
Personally, I’ve started incorporating more walking into my daily routine, like taking the stairs instead of the elevator or enjoying a stroll during my lunch break. These small changes have made staying active feel more manageable and enjoyable.
Finding Balance in Our Sedentary Tendencies
While modern life often requires us to sit—whether at a desk job or during a long commute—Lieberman doesn’t demonize this necessity. Instead, he advises against prolonged periods of uninterrupted sitting. Taking short breaks every 45 minutes to stand or stretch can mitigate potential health risks associated with sedentary behavior.
Organizations like the World Health Organization (WHO) also emphasize the importance of balancing activity with rest. They advocate for regular, moderate physical activity coupled with periods of relaxation to promote overall well-being.
Conclusion
Lieberman’s perspective offers a refreshing take on fitness, one that removes the pressure to engage in intense, continuous exercise. By understanding that our bodies are not inherently designed for constant physical exertion, we can adopt a more forgiving and sustainable approach to staying healthy.
Embracing moderate activity, respecting our natural tendencies, and finding a balance between movement and rest might just be the key to a healthier, happier life. So, if you’ve ever felt out of place in the gym or struggled to keep up with a rigorous workout schedule, remember—it’s okay to take it easy. Your body might actually thank you for it.