From the fine article:<p><pre><code>  &quot;Prolonged and excessive aerobic exercise efforts such as
   marathons, ultra-marathons, full-distance triathlons, and
   very-long-distance bicycle rides are inconsistent with our
   genetic heritage. The pattern of exercise for which we are
   genetically adapted involves a diversity of activities
   performed intermittently, at moderate intensities and 
   moderate durations. Even in highly trained individuals,
   high-intensity, multi-hour endurance exercise effort is
   associated with damage to the myocardial cells and
   connective tissue.&quot;
</code></pre>
If your idea of hunter-gatherer fitness is running marathons all day, perhaps reading the article would enlighten you otherwise?<p>edit: See Table 2 in particular for a list of hunter-gatherer activities and corresponding modern activities. Note only 1 or 2 out of 13 activities involves running.