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Temperature Regulation

Terms in this set (40)

Exercise performance is impaired in a hot environment
- Performance during prolonged, sub maximal exercise (i.e. marathon) is impaired in a hot/humid environment
- Performance during intermittent, high-intensity exercise (i.e. rugby, soccer, 15 min on cycle) is also compromised

Exercise in the heat accelerates muscle fatigue and impairs exercise performance due to a combination of metabolic events:
1) Heat-related muscle fatigue
- During long and intermittent exercise

2) Accelerated glycogen metabolism
- Increased lactate and accumulation and carbohydrate metabolism
- Muscle glycogen depletion and hypoglycemia (low blood glucose) are associated with muscle fatigue during prolonged exercise
- Lower pH caused by increased lactate levels also causes muscle fatigue

3) Increased free radical production
- Damage to muscle contractile proteins (actin and myosin)

4) Reduced muscle blood flow
- During high-intensity exercise
- Caused by cardiovascular strain and a progressive decline in muscle blood flow (due to competition for blood between the working muscles and skin)

5) High brain temperature reduces neuromuscular drive
- Caused by both hyperthermia and dehydration, results in central nervous system impairment
- Hyperthermia acts upon the CNS to reduce the mental drive for motor performance
- Reduction in motor unit recruitment

Key factors that contribute to heat-related muscle fatigue are alterations ink muscle metabolism impaired cardiovascular function/fluid balance, and CNS dysfunction resulting in impaired neuromuscular function