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Melatonin response to exercise training in women
G S Skrinar1, B A Bullen, S M Reppert
1Department of Health Sciences, Sargent College of Allied Health Professions, Boston University, MA 02215.
Journal of Pineal Research
|January 1, 1989
Summary
Vigorous exercise training may decrease daytime melatonin secretion in humans, contrary to previous findings. This study investigated hormonal responses to exercise and found attenuated melatonin levels with progressive training.
Area of Science:
- Endocrinology
- Exercise Physiology
- Chronobiology
Background:
- Previous research suggested daytime melatonin increases with fasting and exercise stress.
- Melatonin, epinephrine, and norepinephrine are key hormones involved in physiological stress responses.
Purpose of the Study:
- To investigate the effects of a progressive exercise training program on daytime melatonin, epinephrine, and norepinephrine levels.
- To compare hormonal responses to exercise before, during, and after a training regimen.
Main Methods:
- Measured plasma melatonin, epinephrine, and norepinephrine levels during treadmill exercise at different intensities.
- Assessed hormonal levels at three time points: T-1 (before training), T-2 (during training), and T-3 (after training).
- Compared hormonal values at T-1 and T-3 to determine training effects.
Main Results:
- Plasma melatonin, epinephrine, and norepinephrine significantly increased with exercise intensity at all time points (P < .01).
- A dose-response relationship was observed for epinephrine and norepinephrine, but this diminished for melatonin.
- Peak melatonin concentration decreased by 52% from T-1 to T-3, while peak epinephrine and norepinephrine decreased by only 19% and 8%, respectively.
Conclusions:
- Vigorous exercise training appears to attenuate, rather than augment, pineal melatonin secretion.
- The findings suggest a potential mechanism for understanding exercise-associated reproductive disorders through a human model of pineal responsiveness.