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Increased prolactin response to hyperoxia at rest and during endurance exercise
H K Strüder1, W Hollmann, P Platen
1Institute of Sports Games, German Sport University, Cologne, Germany.
International Journal of Sports Medicine
|July 1, 1996
Summary
Acute exposure to hyperoxia affects prolactin (PRL) levels before exercise, while hypoxia increases PRL during exercise. Neuroendocrine responses like growth hormone (GH) and ACTH were higher during hypoxia.
Area of Science:
- Exercise Physiology
- Neuroendocrinology
- Sports Science
Background:
- Understanding neuroendocrine responses to varying oxygen levels during exercise is crucial for athletic performance and adaptation.
- Previous research has explored the effects of hypoxia on athletes, but the impact of hyperoxia on specific hormones requires further investigation.
Purpose of the Study:
- To investigate the neuroendocrine responses, specifically prolactin (PRL), growth hormone (GH), ACTH, and norepinephrine (NE), in male athletes under hyperoxic, hypoxic, and normoxic conditions during bicycle ergometry.
- To determine the differential effects of acute oxygen variations on hormonal regulation before, during, and after exercise.
Main Methods:
- Eight male athletes performed 60-minute bicycle ergometry at an intensity of 1.5 mmol/l blood lactate.
- Participants continuously inhaled hyperoxic (100% O2), hypoxic (14% O2), or normoxic gas for 30 minutes before, during, and 30 minutes after exercise.
- Blood samples were collected to measure PRL, GH, ACTH, and NE levels.
Main Results:
- Hyperoxia (HE) significantly increased PRL levels before exercise (400%) but decreased them during exercise, though levels remained higher than in hypoxia (HO).
- Hypoxia (HO) led to an increase in PRL during exercise, while normoxia (NO) showed no significant change.
- Norepinephrine (NE), GH, and ACTH showed significantly higher increases in hypoxia (HO) compared to normoxia (NO) and hyperoxia (HE). NE declined significantly in hyperoxia (HE) before exercise.
Conclusions:
- Acute hyperoxia primarily affects prolactin (PRL) levels, potentially through changes in dopaminergic system inhibition before exercise.
- Hypoxia appears to stimulate a greater overall neuroendocrine response (NE, GH, ACTH) during exercise compared to normoxia and hyperoxia.
- The precise mechanisms underlying these oxygen-dependent hormonal alterations require further elucidation.