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Reproductive hormone increases in response to acute exercise in men
Medicine and Science in Sports and Exercise
|August 1, 1986
Summary
Intense exercise increases serum testosterone, but not due to luteinizing hormone. This study suggests a specific mechanism, likely increased testicular production, drives the exercise-associated testosterone rise.
Area of Science:
- Endocrinology
- Exercise Physiology
- Sports Medicine
Background:
- Serum testosterone increases are commonly observed after intense exercise but lack a clear explanation.
- Existing hypotheses, such as hemoconcentration or decreased metabolic clearance, are non-specific and do not fully account for testosterone changes.
- The role of luteinizing hormone (LH), crucial for testosterone production, has been questioned due to inconsistent findings during exercise.
Purpose of the Study:
- To investigate the hormonal responses to intense exercise, focusing on testosterone and related steroids.
- To determine if exercise-induced changes in other steroid hormones mirror those of testosterone.
- To elucidate the specific mechanisms responsible for the exercise-associated increase in serum testosterone levels.
Main Methods:
- Serum levels of testosterone, androstenedione, dehydroepiandrosterone, cortisol, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin were measured.
- Measurements were taken at 5-15 minute intervals during progressive maximal intensity exercise on a cycle ergometer.
- Hormonal changes were analyzed in relation to exercise onset and duration.
Main Results:
- All measured hormones showed significant increases with exercise.
- Serum testosterone increased prior to exercise, peaked 20 minutes post-exercise, and returned to baseline within 10 minutes.
- Increases in cortisol, androstenedione, dehydroepiandrosterone, and prolactin occurred 25-30 minutes after the testosterone rise, and LH increase was synchronous with testosterone, not preceding it.
Conclusions:
- The exercise-associated increase in serum testosterone is likely mediated by a specific mechanism, not solely by non-specific factors like hemoconcentration.
- The findings suggest increased testicular production of testosterone during exercise, independent of a significant rise in luteinizing hormone.
- This study challenges previous assumptions and points towards a direct, specific pathway for exercise-induced testosterone elevation.