
Originally Posted by
Warrior
Another thing to consider is endogenous androgen levels of drug free athletes. When you put your body through intense cardio training it will try and become more effecient. And carrying a lot of muscle is not effecient. The main reason is that the more lean weight you have the more active your metabolism is - the more calories you need to sustain an activity... the higher you basal metabolic rate is.
Your body will slow down its production of hormones like tesoterone to allow a break down of muscle tissue. Not only to allow for a quick energy source but to allow cortisol and other "distructive" hormones to lower you energy requirements (to lower your lean weight for a slower metabolism) to sustain the activity. The shift allows for a more effecient fuel economy in semistarvation (exercise induced). I know of a few studies that show a reduction in testosterone levels of due to intense, prolonged exercise...
For example... "... 5 athletes participating in an 1100 km run over 20 days demonstrated a reduction to half of normal testosterone levels by the end of the event (Schurmeyer, Jung, and Nieschlag, 1984). Reduction in plasma testosterone levels have been reported immediatly following exercise for marathoners (Dessypris, Kuoppasalmi, and Adlercreutz, 1976), ultramarathoners (Morville, Pesquies, Guezennec, Serrurier, and Guignard, 1979), triathletes (Urhausen and Kinderman, 1987) and cyclists (deLignieres, Plas, Commandre, Morville, Viani, and Plas, 1976)."