Exercised | Daniel E. Lieberman

Summary of: Exercised: Why Something We Never Evolved to Do Is Healthy and Rewarding
By: Daniel E. Lieberman


Dive into the intriguing world of ‘Exercised: Why Something We Never Evolved to Do Is Healthy and Rewarding’ by Daniel E. Lieberman, where you’ll discover that we didn’t evolve to exercise. As you explore the eye-opening information in this summary, you’ll learn about the vital differences between voluntary physical activity and the natural activity we’re designed for. Plus, uncover insights about sleep, strength, the role of walking and running in weight loss, and maintaining an active lifestyle as we age. Whether you’re a fitness enthusiast or someone looking to understand our natural aversions to exercise, this book summary promises to debunk common misconceptions and offer a fresh perspective on adopting and maintaining an active lifestyle.

Evolved to Move, Not Exercise

Contrary to popular belief, humans did not evolve specifically to exercise. Our ancestors were physically active due to necessity rather than voluntarily choosing to exert themselves for health and fitness purposes. It’s essential to understand this distinction to adopt a more empathetic and supportive attitude towards ourselves and others when it comes to exercising.

Picture our early ancestors — you’d likely visualize them actively hunting, traversing challenging terrains, or defending themselves. This physical activity was an essential aspect for their survival, primarily motivated by the need for food. However, this doesn’t necessarily mean they evolved to exercise as we understand it today.

The important clarification here is that exercise is a voluntary act, typically pursued with health and fitness goals in mind. Humans evolved to be active when circumstances demanded it, such as the urgency to hunt for food. Aside from a few exceptions, like dancing and childhood games, unnecessary physical activity was not inherently a part of our evolution.

This lack of natural inclination for exercise may seem unanticipated, but it’s logical when considering the biological need to conserve energy. Movement requires energy, and energy necessitates food. While modern times offer easy access to high-calorie foods to replenish our energy quickly, our predecessors faced a constant challenge in finding enough sustenance. In that context, expending energy on non-vital tasks was risky, potentially jeopardizing survival and reproduction.

So even though it might initially seem counterintuitive, the reason many people find it challenging to exercise is rooted in our evolutionary history. Acknowledging the difference between evolving to be active and evolving to exercise can help foster a more compassionate approach towards our own and others’ reluctancy in adopting a workout regime. We need to recognize that overcoming our inherent instincts can be difficult and requires hard work and dedication.

Understanding this concept doesn’t mean we should give up on exercising altogether. Instead, it’s an opportunity to refocus our perspective on our fitness journey. By appreciating the underlying reasons behind the reluctance to exercise, we can cultivate a more supportive environment that encourages commitment to a healthier lifestyle for both ourselves and the people around us.

Debunking the 8-Hour Sleep Myth

The widespread belief that we need eight hours of sleep each night may not hold true for everyone. Studies have shown that different populations, such as hunter-gatherers, Amish farmers, and rural Haitians, naturally sleep less than eight hours. These findings challenge the conventional wisdom about sleep, revealing that it’s normal to get less sleep than experts recommend, and in some cases, it may even be beneficial to our health.

The modern era has brought about a common concern: the belief that we’re not getting enough sleep. It’s often said that we need eight hours of slumber each night. However, recent studies challenge this notion and shed light on variations in human sleep patterns.

The widely-accepted belief that we need eight hours of sleep every night dates back to the nineteenth century when a catchy slogan of the factory workers’ strike emerged – “Eight hours for work, eight hours for rest, eight hours for what we will!” While memorable, it may not be the best guide when it comes to understanding how much sleep we actually need.

Pioneering research by sleep scientist Jerome Siegel and his team at UCLA delved into the sleeping habits of populations across the globe. They discovered that hunter-gatherer and hunter-farmer groups in Tanzania, the Amazon rainforest, and the Kalahari desert slept, on average, six and a half hours each night – less than their counterparts in industrialized societies. These individuals’ sleep patterns varied by season, with slightly less sleep in summer months and a little more in winter.

Further studies on Amish farmers, rural Haitians, and subsistence farmers in Madagascar revealed similar patterns. These compelling findings suggest that it is perfectly normal to sleep for less than eight hours a night. In fact, research indicates that people who sleep around seven hours might even live longer than those who sleep more or less than this amount.

The takeaway from these studies is that there is no one-size-fits-all approach to sleep. Don’t fret if you don’t consistently get the “recommended” eight hours of sleep each night. If you find yourself struggling with sleep deprivation, consider incorporating regular exercise into your daily routine to help improve your sleep quality.

Debunking Primal Fitness Myth

Contrary to popular belief, our ancient ancestors were not exceptionally brawny. Modern hunter-gatherer populations, such as the Hadza of Tanzania, exhibit lean figures and moderate strength that fall within Western norms. Reasons for their lack of bulky muscles include the difficulty of building muscle with body-weight training and the high caloric cost of maintaining muscle mass. The necessity of being exceptionally strong to attract mates and overcome predators did not outweigh the energy conservation advantages, leading to the evolution of a lean, moderately strong form.

The primal fitness movement postulates that our prehistoric cave-dwelling ancestors were incredibly strong and muscular, thanks to their rigorous lifestyle of hunting and moving massive boulders. According to enthusiasts, our modern sedentariness has resulted in weaker physiques, and we should strive to regain our primitive prowess. However, is this image of superhuman strength truly reflective of our evolutionary past?

Contrary to this theory, evidence from existing hunter-gatherer populations suggests we did not evolve to be naturally brawny. Data on the Hadza tribe from Tanzania, as well as other traditional societies like the Mbuti of Central Africa, the Batek of Malaysia, and the Aché of Paraguay, reveal that their strength and muscle size are comparable to or even below those of Western populations. While undoubtedly fitter than most modern individuals, they do not exhibit the extraordinary muscularity imagined by primal fitness advocates.

The absence of remarkable strength can be attributed to the limitations of body-weight training and the significant caloric costs associated with developing and maintaining muscle mass. Building muscle with only one’s body weight as resistance is challenging, and increased muscle mass necessitates higher energy intake for upkeep. In fact, around a fifth of our energy consumption is directed towards maintaining our muscles, and this proportion increases with more muscle mass.

Considering the evolutionary benefits and drawbacks, the advantages of being exceptionally strong did not surpass the energy conservation boon of leaner bodies. Rather than evolving to become burly warriors, our ancestors developed enough strength to successfully navigate the challenges of their daily lives. The primal fitness concept inadvertently promotes a historically inaccurate and biologically unfounded ideal.

Walking: A Weight Loss Ally

Exercise scientists have debated the effectiveness of walking for weight loss, with some pointing out its low calorie-burning nature and propensity to increase hunger. However, a study found that increasing the amount walked per week to 300 minutes led to more weight loss, proving that walking has a role in shedding pounds. Moreover, walking is crucial for maintaining a healthy weight, as those who exercise regularly are more likely to keep the weight off than those who don’t. Thus, walking should not be dismissed in weight loss and weight maintenance strategies.

Walking has long been a topic of contention among exercise scientists, with many questioning its role in weight loss. The energy consumed during moderate exercise like walking seems to suggest that it should help burn fat. However, others argue that walking is an inefficient method for shedding pounds.

Nevertheless, walking does play a crucial role in weight loss. Critics argue that walking burns few calories and increases hunger, often leading to overeating. Studies supporting this notion found that individuals who walked briskly for 150 minutes per week experienced minimal weight loss.

This lack of dramatic impact can be attributed to our inherent efficiency in walking as a species. While this efficiency is usually advantageous, it makes losing weight through walking more difficult. Fortunately, there is still hope for those who rely on walking for weight loss.

The same study that showed minimal weight loss for individuals walking 150 minutes per week discovered more promising results with a group that walked for 300 minutes per week. After three months, participants in this group had lost an average of six pounds. Extending this progress over a year could potentially result in a 26-pound weight loss.

While walking alone may not be the ultimate key to losing weight, it plays a significant role in maintaining weight loss. Statistics show that within a year of completing a crash diet, individuals who do not exercise are prone to regain half of the weight they initially lost, eventually returning to their starting weight. In contrast, those who engage in regular exercise are more successful in maintaining their weight loss.

In summary, although walking isn’t a miracle solution for weight loss, it plays a valuable role in both shedding and maintaining a healthy weight. Walking’s impact should not be overlooked, especially when combined with other weight management strategies.

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