Past myths related to adverse consequences of masturbation included the view that it caused insanity and blindness. In recent decades, medical opinion has done a reversal pointing to the health benefits of safe sex including autoerotic activity.
Evolutionary psychologists surmise that male masturbation in particular serves an adaptive function. This idea relates to the fact that older sperm loses motility and is thus less effective at competing with the sperm of other males to fertilize an egg (1). Through masturbation, a man may replace sluggish sperms with newer, more mobile ones that are better at fertilizing an egg.
This advantage might explain why more men than women masturbate and why men masturbate more often than women.
While sperm competition may play a minor role in modern societies where monogamous mating is common, and where infidelity is the exception, autoerotic activity is a source of orgasms. Health professionals have come around to the view that orgasms can provide numerous health benefits.
While orgasms produced by intercourse have some differences most of the putative health benefits are similar.
The possible health benefits of sexual activity were revealed in research on cardiovascular health. In one early study, middle-aged Welsh men who experienced three orgasms per week from intercourse had healthier readings on blood pressure and were less likely to experience heart attacks compared to men having one orgasm per week. Their general mortality was much lower.
Of course, such correlational findings are open to different interpretations. Did the men have better health because they were sexually active, or were they sexually active because they were healthier?
Both interpretations seem plausible.
Such early research generated interest in the topic and there is a growing consensus that regular sexual activity promotes health if engaged in a safe context.
Health Benefits of Orgasms
People who have an active sex life take fewer sick days, implying improved immune function.
In addition to improved cardiovascular health, and improved immune function, researchers point to numerous psychological benefits including, improved sleep, reduced anxiety and depression, and higher self-esteem. The drowsiness and relaxation following orgasm are attributable to the release of the hormone prolactin.
Other more specific advantages include increased bladder control in women and reduced prostate cancer in men. Regular sexual activity increases vaginal lubrication and increases vaginal blood flow and elasticity, which boosts pleasure and libido.
Sexual activity reduces sensitivity to pain without the side effects of pharmacological painkillers.
Sex increases heart rate and can thus be described as a minor workout, although it's no substitute for regular exercise.
How Intercourse Differs From Solo Sex
Although orgasms by any means share many common features, there are some intriguing differences. For example, seminal fluid triggers an immune response in the female reproductive tract that has complex implications for health.
The prolactin increase following intercourse is four times as great as that following masturbation in male and female subjects tested in the laboratory. This result was interpreted as suggesting greater “satiety” or satisfaction with implications for happiness and self-esteem.
In the past, there was a great deal of concern about the risks of sexual behavior with an almost exclusive focus on unwanted pregnancy and sexually-transmitted disease. Today, these issues are balanced by a more realistic appreciation of the potential advantages of sexual expression.
1 Baker, R. S., and Bellis, M. A. (1995). Human sperm competition. London: Chapman and Hall.