Thursday, May 12, 2011

Endurance Exercise Turns Out to Be More Manly Than You May Have Thought: 30 Minutes on the Treadmill Raise Muscular Dehydrotestosterone (DHT) Levels

Figure 1: Molecular structure of
dihydrotestosterone (DHT) (from Wikipedia)
I assume jogging is not what crosses your mind, when somebody is talking about "manly" exercises!? DHT, the acronym for dihydrotestosterone, on the other hand, is what experts like Dr John Crisler (from hold responsible for all things male. So, if, as a recent study (Aizawa. 2011) published in the Journal of the American College of Sports Medicine reports, running on a treadmill for 30 minutes, 5 times a week increased dihydrotestosterone levels in skeletal muscle of male rats, it is pretty likely that moderate jogging can trigger similar hormonal changes in men and thus render them "more manly".

What Aizawa et al. found was that an increase in "mRNA expressions of 3[beta]-hydroxysteroid dehydrogenase (HSD), aromatase cytochrome P450 (P450arom) and 5[alpha]-reductase in the skeletal muscle of trained rats" if compared to sedentary controls. These changes in enzymatic expressions induced the following changes in the overall hormonal profiles of the animals:
The muscular dihydrotestosterone (DHT) concentrations in the skeletal muscle of trained rats were significantly higher than that of sedentary rats (P 0.01), but no change in dehydroepiandrosterone (DHEA), total testosterone, free testosterone and estradiol. Furthermore, muscle weight corrected for BW of trained rats was moderately correlated with the level of muscular DHT concentration in trained rats (r = 0.41, P 0.05).
Being 10x as potent as testosterone, DHT is often considered the male hormone per se, with testosterone being nothing, but a "prohormone" to its potent bigger brother. From the fact that testosterone levels remained unchanged in the course of the study, we can yet conclude that the additional conversation of testosterone to DHT (5-alpha reductase) has been compensated by an increase in basal testosterone production.  This being said, the arduous and (by many male trainees) dreaded metabolic work shines in a completely new, much more "manly" light. It is, after all, no coincidence that the most potent anabolic steroids have been "build" on a DHT base. And while, you certainly cannot expect similar explosive gains in strength and lean mass as "on cycle", moderate cardio training may in fact turn out to improve your gains and performance in and out of the gym.

On a side note: In case you are worried about hair loss and prostate cancer, whenever you hear about DHT, or just want to know more about why it is related to "all things male", I suggest you check my previous DHT-related blogposts.