Hypothermia vs Performance By William Misner, Ph.D. Does
Elevated Core Body Temperature & Dehydration Influence Endurance
Performance? Over the course of the past 7 years, reports from
endurance athletes competing in hot or hot and humid events
substantiate that there are times when fluids, fuels, and
electrolytes are consumed at recommended ideal dose do not
result in unsuccessful performance failure. The human body has
great difficulty adapting to heat imposed when dehydration
exceeds 4% loss of body weight and rectal temperature exceeds 39
°C, 102 °F. Fluids bodyweight loss of 4% occurs from evaporative
sweating during aerobic exercise at 60% VO2 Max rate in 95 °F
within 2 hours 11-19 minutes time . The first symptom of
dehydration is dry mouth, which occurs when approximately -2% of
the bodyweight fluid stores is lost. At -4% or more dehydration
dramatically increases core temperatures giving rise to
dizziness, lack of clear thinking, sense of overheating, high
shallow heart rate, loss of motivation, depr