The ability of athletes to complete events such
as the marathon, even in adverse climatic condi-
tions, with relatively little change in body tem-
perature, indicates that the thermoregulatory
system is normally able to dissipate the associ-
ated heat load (Sutton 1990). Nielsen (1996) cal-
culated that a marathon runner competing in a
hot climate would be seriously disadvantaged:
her calculations suggested that a marathon
runner with a best time of 2 h 10 min, competing
in conditions typical of the south-eastern United
States at the time of the 1996 Summer Olympic
Games, would not be able to run faster than
about 3 h 20 min because of the limited heat loss
that would be possible. The winner of the men’s
race at those Games actually finished in a time of
2 h 12 min 36 s compared with his previous best
time of 2 h 11 min 46 s. This apparently minor
effect on performance was in part due to the
environmental conditions being less severe than
expected, but also indicated that the body is
remarkably able to perform even in adverse
environmental conditions. It is also worth noting
that many of the spectacular collapses that have
occurred in the history of marathon running
have occurred in hot weather. Famous examples
include those of Dorando Pietri at the 1908
Olympic marathon in London, Jim Peters at the
206 nutrition and exercise
Fig. 15.2Water may be less
effective for dehydration but
effective for cooling. Photo © Cor
Vos.Fig. 15.3Even in cool conditions temperature
regulation is a big factor in endurance events. Photo
courtesy of Ron Maughan.