Basal reproductive hormonal profiles are altered in endurance trained men.
OBJECTIVE
The purpose was to examine the basal reproductive hormonal profiles in age-matched groups of endurance trained (ET) and sedentary (SED) men under controlled conditions.


METHODS
Resting basal blood samples were obtained from groups of ET and SED men after a 24-hr control period. Blood specimens were analyzed for testosterone (T), free-testosterone (fT), sex-hormone binding globulin (SHBG), luteinizing hormone (LH), cortisol, and prolactin. The design of the study was retrospective and cross-sectional in nature.


METHODS
Laboratory setting at the University of North Carolina, North Carolina USA.


METHODS
ET men (n = 53) who had been involved with chronic endurance exercise training for > or = 5 years. SED men (n = 35) were selected of comparable ages and the fact that they had done no formal exercise training.


RESULTS
Results indicated that the basal T and fT of the ET men were significantly (p < 0.01) lower than that of the SED men. The levels of these hormones in the ET men where in the normal clinical range, but represented only 55% to 85% of those seen in the SED men. For SHBG, LH, cortisol, and prolactin, no significant differences (p > 0.05) were found between the ET and SED men.


CONCLUSIONS
ET men have lowered basal T and fT levels and this suppression may be related to an alteration in the hypothalamic-pituitary-testicular regulatory axis since the LH of the ET was not elevated. Whether these hormonal changes have any significant beneficial (i.e., protective cardiovascular) or negative (i.e., decrease anabolic-androgenic processes) physiologic consequences remains to be determined.
Endocrine Section, University of North Carolina, Chapel Hill 27599-8700, USA.
A C
AC
Hackney
C L
CL
Fahrner
T P
TP
Gulledge
D000328:Adult; D003430:Cross-Sectional Studies; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D008875:Middle Aged; D010807:Physical Endurance / Q000502:physiology*; D011388:Prolactin / Q000097:blood; D012189:Retrospective Studies; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D013739:Testosterone / Q000097:blood
D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D011388:Prolactin; D007986:Luteinizing Hormone; D006854:Hydrocortisone