Central fatigue is a combination of symptoms originating in the central nervous system and can be related to heavy exercise, especially in the heat. The symptoms of central fatigue include the following:
1. Problems controlling temperature.
2. Behavior changes.
3. Mood changes.
4. Problems with mental arousal.
5. Loss of motivation.
Central nervous pathways of two neurotransmitters, serotonin and dopamine, are involved in central fatigue. Serotonin and dopamine alter the production of prolactin by the anterior pituitary. Prolactin levels are shown by the authors to be a marker of central fatigue during prolonged exercise in heat. Elevated prolactin levels define hyperprolactinaemia (hyperprolactinemia.)
CONCLUSION: “Collectively, these results suggest that a combination of thermoregulatory and cardiovascular factors modulate the prolactin response to exercise hyperthermia.” Prolactin levels can be used as a marker of central fatigue.
NOTE: Serotonin is believed to alter prolactin production by acting on the hypothalamus, at the base of the brain. The hypothalamus acts on the pituitary to release prolactin. Dopamine alters prolactin production by acting directly on the pituitary. Read about the effect of dopamine on prolactin.
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