Experimental Physiology 2020 Halsey Are Humans Evolved Specialists For Running In The Heat Man Vs Horse Races

This study investigated whether humans are uniquely adapted for long-distance running in hot weather - a theory that suggests our ancestors may have been "persistence hunters" who could chase down faster prey by outlasting them in the heat. To test this, researchers analyzed race results from three annual "man versus horse" competitions, comparing how running speeds changed as temperatures increased.

The results showed that while horses are faster overall, human running performance declined more slowly than horse performance as temperatures rose. This provides the first direct evidence that humans are indeed less affected by hot weather during endurance activities compared to other running mammals. However, the researchers noted that since humans are still slower than horses and many other animals in absolute terms, our heat advantage alone doesn't fully explain how persistence hunting could have worked.

The study suggests that successful persistence hunting likely required combining our small heat-tolerance advantage with our superior cognitive abilities - using strategy, experience, and mental discipline to eventually exhaust faster prey. This finding supports the broader theory that humans evolved specialized traits for endurance activities, particularly in challenging environmental conditions.

From a clinical perspective, this research reinforces why heat tolerance and endurance capacity are important aspects of human physiology to maintain through proper conditioning, and why gradual heat acclimatization can be beneficial for those engaging in endurance exercise, especially in warmer climates.