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Strenuous exercise with caloric restriction: effect on luteinizing hormone secretion
N I Williams1, J C Young, J W McArthur
1Department of Health Sciences, Sargent College, Boston University, MA, USA.
Medicine and Science in Sports and Exercise
|October 1, 1995
Summary
Strenuous exercise combined with caloric restriction significantly reduces Luteinizing Hormone (LH) pulse frequency in women. Adequate calorie intake appears to prevent these exercise-induced changes in LH secretion.
Area of Science:
- Exercise Physiology
- Reproductive Endocrinology
Background:
- Strenuous exercise can impact reproductive hormone secretion.
- The interplay between exercise intensity, caloric intake, and Luteinizing Hormone (LH) secretion requires further investigation.
Purpose of the Study:
- To determine if strenuous exercise, with and without caloric restriction, alters LH secretion.
- To assess if changes in LH secretion are detectable in the immediate post-exercise period.
Main Methods:
- Four moderately trained eumenorrheic women participated over three menstrual cycles.
- Blood samples were collected before and after 90 minutes of high-intensity running (74% VO2max).
- Three conditions were tested: CONTROL (eucaloric, no exercise), STTI (eucaloric, strenuous exercise), and DIET/STTI (60% caloric intake, strenuous exercise).
Main Results:
- A significant decrease in overall LH pulse frequency was observed during the DIET/STTI condition compared to CONTROL and STTI.
- No significant changes were found in mean serum LH levels or peak LH amplitude across conditions.
- These findings indicate that caloric restriction exacerbates exercise-induced alterations in LH pulsatility.
Conclusions:
- High-volume training combined with caloric restriction may increase susceptibility to exercise-induced changes in LH pulse frequency.
- Sufficient caloric intake may mitigate the impact of strenuous exercise on LH pulse frequency.