I had the opportunity to answer some questions relating physical exercise, hormone production, and sex drive for a reporter involved in launching an upcoming website, Giddy, dedicated to publishing sex-positive information.

Q: I know exercise = endorphins, which make you happy, but what exactly do endorphins have to do with libido?

A: There is evidence suggesting the role of endorphins in sexual function and sexual behaviors given these hormones may regulate the release of sex hormones from the pituitary gland which are involved in sexual function.

Q:Does exercise boost other hormones (like serotonin or dopamine) that help increase sex drive, and, if so, how?

A:Yes, regular exercise boosts serotonin, dopamine, growth hormone, and testosterone levels. In the case of dopamine, exercise stimulates the brain’s reward centers ultimately boosting dopamine production which is very important in sexual arousal and function. With serotonin, especially aerobic exercises trigger the release of tryptophan, a substrate for the synthesis of serotonin, into your blood. Interestingly, serotonin is an inhibitor of libido whereby low levels are associated with increased sex drive while higher levels are associated with the production of oxytocin, the love or ‘cuddling’ hormone. Regarding growth hormone(GH), aerobic and resistance exercises are powerful stimuli for GH production which increases blood circulation, exercise capacity, and the pleasure associated with sexual activity, all important for sexual function. High-intensity interval and resistance training are good means to promote Testosterone levels while endurance training has the opposite effect. Testosterone physiologically stimulates sex drive and low levels of this hormone are associated with erectile dysfunction and low libido in men as well as low libido in post-menopausal women.

Q:I know exercise leads to increased blood flow—how would that stimulate your sex drive, specially for men?

A: Exercise improves cardiovascular function so blood can flow more easily to the genitals, which is good for arousal and sexual function.

Hi Dr. K — Thanks for getting back to me! I have two quick follow-up qs, just to provide a little more detail for readers:

Q: I’m not 100% sure what you’re saying here. Is it that endorphins may regulate the release of sex hormones from the pituitary gland? If so, what sex hormones may be released?

A: These are called the gonadotropins which stimulate the testes to produce sperm, the ovaries to produce eggs, and the sex organs to produce the sex hormones testosterone and estrogen. The process starts when exercise stimulates the hypothalamus to produce gonadotropin-releasing hormone which travels via tiny blood vessels to the pituitary which responds by producing follicle-stimulating and luteinising hormones. These hormones enter the bloodstream and act on the sex organs to control the production of the sex hormones as well as to maintain their reproductive functions.

Q: I want to be crystal clear as to how this benefits male readers here: With more blood flowing to their genitals, could they experience a harder erection? Could they reach orgasm sooner?

A: A big yes! In the article: “Enhanced sexual behavior in exercising men”, Archives of Sexual Behavior, Vol. 19, pgs. 193-209, 1990; a 9 month study took 2 groups of middle-aged, sedentary men and had one group implement frequent, vigorous aerobic exercise while the other performed moderate exercise such as walking. The researchers found that the frequency of sex, genital function reliability, percentage of satisfying orgasms, and overall fitness were all significantly enhanced in men following the vigorous aerobic exercise program.