AUTHOR=Bouscaren Nicolas , Millet Guillaume Y. , Racinais Sebastien 

TITLE=Heat Stress Challenges in Marathon vs. Ultra-Endurance Running

JOURNAL=Frontiers in Sports and Active Living

VOLUME=Volume 1 - 2019

YEAR=2019

URL=https://www.frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2019.00059

DOI=10.3389/fspor.2019.00059

ISSN=2624-9367

ABSTRACT=Several studies have investigated the effect of hot and humid ambient conditions on running exercise up to the marathon. However, studies on exercise longer than marathon are sparse. Events exceeding 6 hours can be defined as ultra-marathons and have variable characteristics (e.g. distance, elevation profile, technicity of the terrain, altitude, night running) making hazardous the transposition of the current knowledge obtained in marathon to ultra-marathon. Thus, the aim of this manuscript was to discuss the potential differences between marathon and ultra-marathon in terms of thermoregulatory challenges. The high running intensity (especially for the fastest runners), the urban context with high albedo effect materials, and the hot microclimate self-generated in mass-participation events (especially for the average to slow runners) are specific risk factors associated with marathon running in hot environments. Uphill running/walking (sometimes with poles), exotic destination with long-haul travel, desert environment and the necessity to sustain a thermoregulatory and sweating responses for several days are risk factors more specific to ultra-marathon. These differences called for specific research on the effect of hot ambient conditions in ultra-endurance disciplines to create appropriated recommendations.