Every day, our ancestors spent hours walking and running. Anthropology studies suggest that they covered a lot of ground. Men are thought to have moved between 10 to 20 kilometres in hunting each day. Women spent more time gathering, and so went about half that distance. In comparison, chimpanzees only walk two to four kilometres a day. Other apes trek even less, as they live in dense forests where food is easy to find.
As the staple food providers, hunter-gatherer women likely walked five to 10 kilometres each day. Foods brought by men required hunting, scavenging and being in the right place at the right time. Successful hunts were likely followed by a rest day, since hunting involved very heavy exercise. The total activity and energy used would have varied more for males.
Hunter-gatherers most likely evolved into runners. Chasing and tracking prey would have formed a large part of the hunting process. Anthropological evidence points to many changes in the human skeleton and muscles. These changes can only be explained as adaptations to allow running. Long, springy tendons developed in the legs and feet. The benefit of these tendons, like the Achilles tendon, is that they work like a large elastic, storing energy and releasing it with each running stride. Less energy was needed and an efficient running style developed.
We may not think of our ability to rotate our shoulders independently of the head and neck as a running adaptation. However, such movements clearly allow better balance. As well, arm swings balance us with each step we take.
Our gluteus maximus muscles (buttocks) keep our upper bodies stable in the upright position. These muscles are key in stabilizing us as we lean forward at the hip during running. They keep us from pitching over each time a foot strikes the ground.
What can the human record of energy use and movement teach us? Well, running has long been an important part of life. Frequent, long-distance aerobic exercise played a major part in how humans evolved. High rates of speed were not as important as combining reasonable speed with endurance. This gives an excellent guide to how we should exercise in our modern world.
We know that regular physical activity is linked to many changes in the body that reduce the risk of chronic disease. For instance, aerobic activity of a prolonged duration affects muscle and fat tissue, making the body more likely to use fat as a fuel source. This increases our capacity for exercise, since less carbohydrate stores need to be used to power the muscles. More physical activity helps those with diabetes, since it improves the body’s ability to use insulin.
Generally anyone with a chronic disease such as type 2 diabetes or high blood pressure will benefit from using more energy. Exercise may reduce symptoms related to the disease. This in turn lessens the stress of managing the condition.
Guidelines used today are loosely based on the 1996 U.S. Surgeon General Report. People of all ages should accumulate at least 30 minutes of moderate physical activity on most, if not all, days. This amount of physical activity is roughly the same as using 150 kcal per day or 1,000 kcal per week.
The report also talks about a dose-response relationship for physical activity and health. For instance, 45 minutes of brisk walking each day will result in a weight loss of one pound per week. Increasing physical activity will result in reduced weight, mostly fat loss. In other words, vigorous or long-lasting exercise brings better health benefits and weight control.
You can also e-mail a request to firstname.lastname@example.org to get a copy.
Canada’s Physical Activity Guide to Healthy Active Living from
Alvin Powell’s article, Humans hot, sweaty, and natural-born runners, which can be found here.
Many of us today do not consider ourselves natural runners. However, we can still learn from our ancestors why the current exercise guidelines make practical sense.
In the past, humans likely did ‘persistence hunting.’ Hunters would chase game in the heat of the day, pushing an animal at a faster pace than it could maintain. The hunter would then track and drive it out from hiding when it tried to rest. We can consider this method of hunting an exercise model that combines intensity with longer aerobic activity.
The key for our modern exercise prescription is to spend a third of the activity time doing higher intensity exercise. Increase your speed or pace as a hunter would in making an animal run faster than it would on its own. Go at your own pace for the remaining two-thirds of the exercise time. You will gain health benefits from this type of exercise program by continuously improving the related aerobic components. For example, for 15 minutes of your 45-minute walk, walk as briskly as you can. If you jog, run two of your five kilometres as fast as you can.
With this prescription in mind, we will continue to evolve positively and gain the benefits of physical activity. We won’t be running away from the health, active lifestyle our ancestors followed.