Sometimes, as a scientist, you make a discovery that you wish you hadn't made. If you publish your findings, you know that some people will interpret them wrongly and act irresponsibly. This is what happened to sports scientists at the University of North Texas. They discovered that taking a hefty dose of alcohol after a strength training session leads to a significant rise in testosterone levels.
The favourite hard drug in many regular sports is ethanol ? the chemical name for the alcohol in beer, wine and spirits. But it's strange that ethanol should be so popular among sportspeople. The endocrinal effects of alcohol are exactly the opposite of what athletes strive for.
First of all, chronic alcohol intake damages the Leydig cells in the testes, which are the cells that produce testosterone. That's why ethanol lowers testosterone production. [Endocrinology. 1980 Jun;106(6):1880-5.] Studies have shown that alcohol consumption results in an acute drop in men's testosterone levels. [J Pharmacol Exp Ther. 1977 Sep;202(3):676-82.]
Secondly long-term use of alcohol stimulates enzymes in the liver which convert testosterone into estradiol and also inhibits the manufacture of androgen receptors. [Toxicology. 1990 Jun;62(3):285-95.] In the study we mention here the author refers to alcohol use as "a chemical form of castration".
Thirdly, research on alcoholics has shown that alcohol boosts the concentration of the transport protein SHBG in the blood. SHBG binds testosterone in such a way that it is no longer active. [Eur J Clin Invest. 1981 Dec;11(6):473-9.]
The effects of post-training alcohol intake have been well documented. They are negative. If you drink alcohol after doing strength training, your muscles recover less quickly. Might this be because alcohol sabotages the effect of testosterone? We don't know. Not much research has been done on the relationship between strength training, testosterone and alcohol. So the researchers at the University of North Texas decided it was time to do something about this.
They got eight men aged between 21 and 34, all of whom were experienced in strength training, to do 6 sets of squats with a weight at which they could just manage 10 reps. Ten minutes after completing their last set the men were given on one occasion a placebo and on the other occasion 1.09 g alcohol per kg bodyweight. To give you an idea: thats about 10 g alcohol per drink.
Just before [Pre], just after [IP] and up to 300 minutes after finishing the workout the researchers measured the testosterone level of their subjects ? and saw that they rose more after they had given the subjects alcohol.
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There was no change in concentration of estradiol, cortisol or SHBG in response to alcohol intake.
This was not such a surprise to the researchers. Animal studies, in which male rats are given alcohol, show that the number of androgen receptors in the type-2 muscle fibres goes down. Strength training can not delay the breakdown of androgen receptors that occurs as a result of drinking alcohol. [Med Sci Sports Exerc. 2005 Nov;37(11):1842-8.]
Alcohol destroys receptors that testosterone can attach itself to. This is why the concentration of testosterone in the blood rises, the researchers think.
"Thus, the primary finding of this study, that total and bioavailable testosterone concentrations were elevated acutely after postresistance exercise ethanol ingestion, should be interpreted with care", they write. "If testosterone release is increased, this could be beneficial; however, if muscle uptake is reduced, this could be detrimental to the desired adaptations".
"Therefore, the findings of in the present study should not be seen by coaches and athletes as evidence that ethanol ingestion after resistance exercise is beneficial to their conditioning program."
Med Sci Sports Exerc. 2013 Sep;45(9):1825-32.