While I’m still thinking of exercise from my last post about exer-gaming, I ran into a fascinating paper in the Journal of Applied Physiology the other day. It was about some of the physiological changes and stresses induced by training for, participating in, and completing an Ironman triathlon.
Such events are typically today thought of as extreme endurance events, the sort of freakish thing typically taken on only by outrageously fit athletes. But as the paper (“Hemodynamic and autonomic changes induced by Ironman: Prediction of competition time by blood pressure variability”) points out, most trained athletes participating in such events show no significant physiological impact by three days after the event:
The rapid recovery after what we consider now to be an extreme endurance exercise may throw some light on the true capabilities of the human body acquired during human evolution. For the largest part, namely for the 5 million years of the hunter-gatherer age, mankind had to perform daily a regimen of 10 up to 30 km of walking and running for survival. This would correspond to up to 4-h daily exercise time and a WNET [weekly net exercise time] of 28 h. Our “well-trained” athletes achieved only between 20% and 60% of this duration of training, which demonstrates the change of perspective that occurred with the beginning of the industrial age.
In other words, what we now think of as preparing for an extreme endurance event is actually just half the metabolic expenditure of what was commonplace for humans for 5 million years. There is more on this fascinating subject in a wonderfully interesting 2003 paper from the journal Nutrition, abstract available here.