Vitamin C maintains endurance athletes' testosterone levels
Performing endurance sports reduces testosterone levels. [Eur J Appl Physiol. 2003 Apr;89(2):198-201.] This happens, for example, if you run for longer than 45 minutes. [Eur J Appl Physiol. 2005 Aug;94(5-6):505-13.] Pharmacologists at the BJ Govt Medical College in India did an animal study which seems to have uncovered a surprisingly simple way for endurance athletes to limit the reduction in their testosterone level: supplementation with vitamin C.
Vitamin C and testosterone
Ten years ago researchers from Firat University published an animal study in which a megadose of vitamin C boosted testosterone levels. [Theriogenology. 2005 Apr 15;63(7):2063-72.] Converting the figures, an adult human would need 3 to 7 g vitamin C a day to induce a modest rise in testosterone level.
In the animal study that the Indian researchers published in the Journal of Clinical and Diagnostic Research male rats were given less extreme doses. The human equivalent of these would be about 140, 280 and 420 mg per day.
The researchers got rats to swim to the point of exhaustion on 15 consecutive days [Exercise; Stress]. Some of the lab animals did not swim [Normal].
The fortnight of physical exertion lowered the rats' testosterone level, as the figure below shows. When the rats were given vitamin C 30 minutes before they started swimming, however, the decrease in testosterone was less.
The physical exercise reduced the rats' fertility, probably because of the release of free radicals during their exertions, which damaged the testes. Supplementation only partially negated the reduction in sperm quality, the table above shows.
The physical exertion reduced the percentage of pairings the researchers discovered when they placed sexually mature females in a cage with the lab rats. Administration of vitamin C limited the decline in sexual interest. Copulatory index = an indicator of the animals' interest in sex.
"Vitamin C supplementation improves the stress induced reproductive infertility possibly mediated through an increase in testosterone and an antioxidant effect", the researchers write.
J Clin Diagn Res. 2014 Jul;8(7):HC05-8.
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