Our bodies are adapted for enduring some of the harshest conditions on earth. Societies have been known for thousands of years to live in areas of extreme climates, limited resources and maximal competition. In fact, a closer look at our metabolic activity would clearly demonstrate that we are hard wired for high levels of energy expenditure in natural outdoor settings. In our modern world, where people are requiring increasingly less energy to perform daily tasks (think running tap water vs collecting from a nearby stream for example), we are seeing a collective decrease in physical fitness and health.
So, with all of our technology on hand, why are we not healthier?
A collaborative study by researchers O'Keefe et al, analysing the effects of this drastic shift in physical activity has an answer: train like a cave man.
For nearly 84,000 generations, our ancestors survived as hunter-gatherers. To survive in the wild, our ancestors expended high levels of energy foraging for food and water, building shelters, avoiding predators and interacting socially. Fast forward to our current generation and thanks to technological innovation, we are capable of performing most daily dasks with minimal energy expenditure. But at what cost do these advances come?
| O'Keefe et al suggest that "a human being, when unchained from the highly variable and physically taxing daily chores that were required of the hunter-gatherer lifestyle and instead relegated to an indoor overfed sedentary existence, becomes ridden with disease and debility". Infact, its well documented that physical activity- including endurance, strength training and cross training, has instant and far reaching effects on cardiovascular health, life expectancy, musculoskeletal health, general fitness, heart and lung function, blood pressure, metabolism, mood, sleep quality and immunity. Infact, exercise is so important that cardiovascular fitness and daily expenditure on physical activity are some of the best predictors of life expectancy and health. |
So, in a world where many of our needs can be met by typing cues into a small laptop, how can we overcome the debilitating effects of technology?
One way is to learn from the exeperiences of Anthropologist, Kim Hill, PhD, who spent 30 years living with and studying the Ache Hunter Gatherers of Paraguay. In hunting with the Ache, Hill discovered that they covered on average 10km per day and often another 1-2km per day in rapid pursuit of prey. He found their pattern of exercise typically involved moderate exercise days and some very hard days, which were usually followed by easy days. The only limiting factor was rainfall, where they would only perform 1-2 hours of exercise in daily chores. A step test performed on the Ache, undertaken by Hills' students, showed that Ache adults aged 30-50 years of age had significant aerobic conditioning in comparison to their American counterparts.
Given that we don't live the life of the Ache, O'Keefe et al suggest that we opt for a routine of 45 to 90 minutes of cumulative daily physcal activity to attain and sustain our body weight in the ideal range. They found that the combination of aerobic and strength training was most effective for improving hyperglycemia for individuals with type 2 diabetes mellitus and that interval training produced "better weight loss, superior glucose control, and greater fitness gains than equivalent or longer amounts of continuous lower intensity activity". The researchers also suggest training outdoors, citing studies which demonstrate that exercise performed outside provides added benefits for health and well-being, including sunlight exposure that stimulates the absorbtion of vitamin D.