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Hormonal responses during a prolonged military field exercise with variable exercise intensity.
- Source :
-
European journal of applied physiology [Eur J Appl Physiol] 2008 Mar; Vol. 102 (5), pp. 539-46. Date of Electronic Publication: 2007 Nov 27. - Publication Year :
- 2008
-
Abstract
- The purpose of the present study was to test the hypothesis that the magnitude of hormonal concentration alterations during a prolonged military field exercise with constant energy intake (EI) is influenced by changes in energy deficit (ED) induced by varying the exercise intensity. Basal serum hormone concentrations were measured in a group of healthy young male volunteers (n = 7) during a 20-day field exercise. During the first week of the exercise, the average ED was 4,000 kcal/day (P-I), in the second week only 450 kcal/day (P-II), and in the last week 1,000 kcal/day (P-III). During the first 5 days of the field exercise, significant increases in cortisol (COR, +32%) and growth hormone (GH, +616%) concentrations were observed, while insulin (INS, -70%), total testosterone (TES, -27%), free testosterone (TES(free), -26%) decreased. However, after these initial responses, COR and GH returned to the pre-exercise level by the beginning of P-II. Also TES and TES(free) recovered to the pre-exercise level by the beginning of P-III, and INS by the end of P-III. The concentration of TES (+29%) increased above the pre-exercise level by the beginning of P-III. Serum thyroxin (T(4)) concentration was significantly lesser (-12%) and urine urea concentration significantly higher (+78%) after the field exercise than before it. Therefore, it can be concluded that the lower levels of ED in the second and third phase (ED <1,000 kcal/day) allowed recovery of hormonal changes observed in the first phase with ED much greater than 1,000 kcal/day.
Details
- Language :
- English
- ISSN :
- 1439-6319
- Volume :
- 102
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- European journal of applied physiology
- Publication Type :
- Academic Journal
- Accession number :
- 18040709
- Full Text :
- https://doi.org/10.1007/s00421-007-0619-0