Kinesiology 2236A/B Lecture Notes - Lecture 18: Heat Cramps, Heat Syncope, Heat Exhaustion
26 Mar 2019
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Lecture 18 - Heat and Hydration
Temperature
• As atmospheric temperature increases, the temperature gradient between the air and the body
decreases
• When body temperature is greater than atmospheric temperature, we lose heat via radiation
• If the atmospheric temperature is over 27 degrees, the body absorbs heat
o Heat loss from evaporation only
Exercise in the Heat
• Heat is generated by endogenous sources
o Muscle activity and metabolism
• Exogenous sources as well
o Transfer to body
• When an athlete exercises in a hot environment they sweat to dissipate heat
• An increase in humidity will decrease the vapour gradient, causes less evaporation
• Humidity:
o Can be dangerous if it is substantial
Heat Definition
• Heat cramps - muscle cramps, spasms
o Spinal cord issue
• Heat syncope - fainting due to heat
o Blood pooling issue
• Exertional heat stroke (EHS) - when the patient presents with exertion-related hyperthermia and
associated CNS disturbance or evidence of other end organ system damage
o May first experience dizziness, weakness, nausea
o May collapse
o May stop sweating
• Heat exhaustion - an inability to continue functioning in the head without evidence supporting the
diagnosis of EHS
o Signs and symptoms are variable
The Athlete with EHI
• Non-severe (heat exhaustion)
o Primary:
• Conscious
• Alert
• Temperature < 40
• Systolic < 100
o Secondary:
• May or may not be present
• Sweating
• Pale, moist, cool skin
• Cramping
• Nausea
• Severe (heat stroke)
o Primary
• Unconscious or decreased mental status
• Disorientated
• Temperature > 40
