Exercise (light and moderate) can be beneficial to one’s sexual functioning. It can boost serotonin, melatonin, HGH and androgen hormones release. It burns fat, improves insulin resistance, and increases the norepinephrine levels. Exercise also improves blood circulation and eliminates stress hormones, thus resulting in a supercharge of the parasympathetic nerves.
Exercise can prove to be temporarily disabling and harmful if it happens to consume more testosterone than the body can produce. As for teenagers and young men (younger than 25), exercise deactivates the negative feedback loop and results in increased human growth hormone (hGH) production. For people passing 20-25, the pituitary function will naturally slow down and violent exercise may consume too much testosterone without activating sufficient HGH (human growth hormone) production, resulting in penile shrinkage. Prolonged exercise will lead to other highly negative effects as well, such as: neuro-endocrine fatigue (excessive glucagon, norepinephrine, epinephrine and cortisol) for many hours. This excessive dopamine-norepinephrine-epinephrine level in the brain and adrenal medulla will lead to a functional disorders of the hypothalamus-pituitary-testicular axis. It will overdischarge bioelectric energy in the parasympathetic and sympathetic nervous systems, thus forcing the body to consume large amounts of hGH, testosterone and DHEA hormones in order to rebuild and restore your joints and muscles, leaving nothing for sex and libido.
Over-exercising will also lead to chronic pains and spasms due to lacks of prostaglandin E-1 (through the increased E-2 production) in the fatigued tissues. Post-exercise stress and inflammation will most certainly prolong cortisol, endorphin and prolactin release, thus shutting down oxytocin, DHEA, DHT and testosterone production from the hypothalamus-pituitary-adrenal and testicular axis. Also, over-stretching a tissue can eventually lead to collagen scarring for blood congestion and poor circulation, associated with chronic muscular or joint pain and spasms. The pointed out bio-processes that take place if one over-exercises, will shrink the penis. It’s not advisory to mix acute or prolonged exercises with excessive sex, since such a combination can produce excessive cortisol, epinephrine and prolactin, lasting for many hours or days.
If severely overdone, exercise can bring death through the complete depletion of electrolytes in cerebrospinal fluid. Some athletes and body builders will end up impotent, dead or with muscle and joint pains and cramps, that is if their hGH, testosterone and DHEA in the bloodstream runs low. That is why athletes and body builders are likely to take different dietary supplements. Moreover big muscles contain many hormonal receptors that compete with these in the prostate and the penis.