Physical Activity

maasai-adumu

The Maasai jumping dance.

For more than 99% of the evolutionary history of our species, some type of regular physical activity was an essential part of the daily life of virtually everyone. For most of that time, we lived as hunter-gatherers in Africa – and following the migration out of Africa about 70.000 years ago, also in various other habitats around the world.

We evolved to be physically active.

From physically active hunter-gatherers to sedentary office workers

Hunter-gatherers regularly engage in various forms of physical activity, as survival depends on being able to procure food, build shelter, evade dangerous animals, etc. Forager communities are characterized by a division of labour, where males do most of the hunting, while females have a greater responsibility when it comes to gathering plant foods and taking care of young children.

Some general characteristics of the physical activity patterns of hunter-gatherers: (1, 2, 3)

  • Plenty of light-moderate activity such as walking, carrying, etc. On average 6 to 16 km per day!
  • Hard days were typically followed by an easier day.
  • Walking/running on natural surfaces (e.g., grass, sand).
  • Physical activity was performed barefoot or with minimalistic footwear.
  • Occasional intermittent bursts of moderate-to-high level intensity exercise with intervening periods of rest and recovery.
  • Rotation among many different forms of exercise, such as strength training (e.g., lifting stones, carrying logs), endurance training, climbing, etc.
  • Virtually all exercise was performed outside.
  • Primitive populations usually hunt and gather in groups, rarely alone. Evidence also suggests that humans and dogs have co-evolved for as long as 135000 years. Our prehistoric ancestors could have domesticated wolves which took part in cooperative hunting.
  • Dancing was often performed as a part of rituals and celebrations.
  • Occasional sexual activity.
  • Ample time for rest, sleep, and recovery.

With the transition to farming about 12.000 years ago, humans started to settle down in larger communities, and a forager lifestyle was gradually replaced with a subsistence mode that revolved around domesticated animals and plants. Some estimates suggest that early farmers had physical activity levels (PALs) as high – or perhaps even higher – than hunter-gatherers, but the types of activities performed changed, with more resistance-type training in favor of running and walking (4).

The Industrial Revolution – the transition to new manufacturing processes in the period from about 1760 to sometime between 1820 and 1840 – had a profound impact on the types and amounts of physical activity performed. New machines allowed farmers to spend fewer calories to get their job done, and more and more people started to work in factories. The Industrial Revolution initiated many changes that eventually led to plummeting physical activity levels in the modern world.

Up until very recently, virtually everyone had to engage in some type of regular physical activity to acquire food, make a living, and/or survive. In today’s society – where so many have sedentary office jobs and use private transportation to get around – physical activity has become voluntary for many people. We have created an environment where we can choose to be sedentary for our entire lives.

Physical activity that falls outside of what we’re adapted for

Too little 

One important thing to remember is that hunter-gatherers didn’t move their bodies to improve their health or body composition, but because they had to. Those who weren’t physically fit enough to gather food, get away from dangerous animals, build shelter, etc. were weeded out of the gene pool through natural selection. However, this has completely changed in the modern world, where we’ve created an environment where food is readily accessible, dangerous animals are a thing for the zoo, and modern technology allows us to build comfortable homes without exhausting ourselves.

For millions of years, natural selection favoured the preverence and accumulation of heritable traits that improved survival and reproduction in various and diverse natural environments. For our primal ancestors, expending more energy than what was necessary to procure food, evade dangerous animals, etc. had negative survival value. It therefore doesn’t come as a surprise that we’re hard-wired to take it easy when we can, a trait that was adaptive in an ancestral environment, but sets the stage for chronic inactivity and disease in a world of abundance. The problem isn’t necessarily that the average westerner has less willpower or discipline than the prehistoric man; it’s simply that we no longer need to be active.

Estimates suggest that hunter-gatherers’ physical activity energy expenditure was in the range of 800 to 1200 kcal per day, a number that is 3 to 5 times higher than that of modern sedentary individuals (1). Our anatomy and physiology evolved over millions of years to support a physically demanding hunter-gatherer lifestyle. We’re not adapted for a sedentary lifestyle.

Why Does the Body Maladapt to Inactivity?

A general answer to the question is that ancient metabolic and signaling pathways require a minimal threshold of transient flux between energy expenditure and storage and that chronic physical inactivity falls below this threshold (5).

Too much

While our ancient ancestors certainly lifted heavy things, they never performed the 20 set chest workout some strength trainees do today. Of course, the fact that hunter-gatherers didn’t perform heavy barbell training or push-ups doesn’t mean we shouldn’t. However, an evolutionary perspective suggests that we should be “cautious” when we design our strength training program, making sure we don’t put excessive stress on our body.

If we combine the evolutionary template with modern science it’s clear that a more moderate volume and somewhat higher frequency is superior to “extreme” bodybuilding-type training (e.g, completely destroying each muscle group once a week) (5).

The same thing applies to aerobic exercise. Although our prehistoric ancestors often covered many kilometers per day, they rarely performed the type of high-intensity, prolonged aerobic training most long distance endurance athletes do today. While many people consider athletes involved in ironman, triathlon, and other extreme endurance activities to represent the peak of human health, the fact is that the type of chronic cardio that is required to perform optimally in these events is linked to adverse health effects, such as oxidative stress and increased cardiovascular risk (1).

Too new

Many of the activities described in the too much section also fall into this category. Of course, not all novel stimuli are bad; but oftentimes it can be. Exercise machines such as the chest press are frequently used with no apparent problems, but as these types of machines tend to put the trainee into unnatural movement patterns, the exercises performed are clearly less effective and more dangerous than properly performed exercises that allow for natural movement patterns. Physical activities (e.g., deadlift, running) performed with poor technique can also be lumped in the too new category, since our bodies never evolved to be stressed in these novel ways.

Practical applications

By looking at physical activity through the lens of evolution we get a better understanding what types of activities we should include in our exercise program, as well as the duration, intensity, volume, and frequency our bodies can handle. By combining this evolutionary perspective with modern science and practical experience, we get a good idea of how to design effective physical activity programs.

Physical activity comes with a wide spectrum of benefits, such as improved metabolic and cardiovascular health, increased protection against several types of chronic diseases, enhanced bone strength, and improved body composition. All of these effects can be tracked back to the positive impact exercise has on gene expression, an area where a hunter-gatherer fitness style regimen really shines (1, 6, 7). It won’t get you ready for the bodybuilding stage or Tour the France, but it will ancestralize your gene expression pattern (1, 6, 7). If your goal is to achieve good health and develop multifaceted fitness, a hunter-gatherer fitness style regimen is a great choice.

However, it’s important to note that a hunter-gatherer fitness regimen will make you a “generalist”, it will not cause a specific adaptation to one type of activity. In other words, hunter-gatherers didn’t exercise with a definite performance objective in mind, and they didn’t specifically focus on progressive overload; they simply did what was necessary to survive. And this is where we get into the distinction between exercise and training. As strength coach Mark Rippetoe puts it; exercise is primarily performed for the effects it produces today, while training is performed with a long-term performance goal in mind (8). In other words, while exercise often features “random” exposures to a wide range of activities, training is about creating a specific adaptation to eventually reach specific goals.

If we use the example of someone who wants to build muscle and strength, the main focus should be on strength training and progressive overload in a set of compound lifts. Besides these main activities, sprinting, rowing, light-moderate activities such as walking and some occasional HIIT will help confer good health. These activities can either be performed as sporadic exercise, with little focus on progressive overload, or they can be performed as an essential component of the training program.

Finding the right balance is the key. If you always stick to a strict program and constantly try to add more and more weight to the bar, you might end up stagnating and/or losing some of the joy of exercising. However, if you’re always messing around with different exercises and don’t keep track of your progress, you won’t get optimal results. For strength trainees, putting most of the emphasis on the compound lifts is usually a good idea, but including some random “pump” work, unplanned exercise sessions, etc. is also important. For individuals with other specific performance goals (e.g., aerobic endurance, sprinting) the same principles apply; the emphasis should be put on creating a specific adaptation.

For those who train hard several times per week and have specific goals, the key is to train as hard as possible without doing too much.

General recommendations:

  • Learn good exercise technique!
  • Perform plenty of light-moderate activities such as walking.
  • Do some type of regular strength training where you focus on compound movements such as squats, lunges, deadlifts, push-ups, pull-ups, and presses.
  • Occasionally sprint and perform intermittent bursts of moderate-to-high level intensity exercise with intervening periods of rest and recovery.
  • Avoid excessive high-intensity, prolonged endurance training (“chronic cardio”), and be careful not to take bodybuilding-type training to the extreme. “Not too much and not too little”.
  • Preferably use minimalistic footwear or train barefoot.
  • Perform some of your exercise outside if possible.
  • If your goal is to achieve good health and develop multifaceted fitness, a hunter-gatherer fitness style regimen (as loosely described above) is a good foundation.
  • If you have specific goals (e.g., maximize strength and/or muscular development, run a marathon, or sprint as fast as possible), you can still employ many elements of Paleolithic physical activity patterns in your training and use the evolutionary template as a foundation for designing your workout programs, but you should specify your training, focus on progressive overload, and in most instances, keep a training journal.
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