Researchers at Dartmouth College conducted a study suggesting that runners who are taller, leaner, and possess longer limbs may have an edge in endurance events held in warmer climates, while marathon runners with chunkier, shorter limbs could perform better when temperatures are cooler. The findings were published in PLOS ONE, adding to the growing conversation about how body proportions relate to climate across athletic disciplines.
In their analysis, the investigators tracked data from nearly 200 triathletes over a span of twenty years. Triathlons, which combine running, swimming, and cycling across roughly 240 kilometers, provide a unique lens on how athletes regulate heat and maintain performance. The researchers observed that running outcomes appeared to be influenced by how well an athlete7s physique is suited to heat dissipation or retention in different environmental conditions. In other words, body form may influence the physiological strategies athletes rely on to stay cool or stay warm during competition, which in turn shapes endurance performance in specific climates.
According to the authors, this study is among the few that connect human physiology to the Bergmann and Allen rules. Named after 19th-century biologists Carl Bergmann and Joel Asaph Allen, these guidelines link the general body size of animals and the length and thickness of their limbs to climate. The researchers note that, while the rules were originally formulated for nonhuman species, patterns in human athletes appear to echo these ideas, suggesting climate-driven body proportions might partially explain differences in endurance performance across environments. The study, reported by PLOS ONE, emphasizes the potential relevance of anatomical traits for athletic success in warm versus cold settings and invites further exploration into how heat exchange and limb morphology interact during extended exertion in real-world conditions.