Benefits
The physical benefits of masturbation and having an orgasm or ejaculating creates heightened arousal while epinephrine courses through the body, producing the flushed face, shallow breath and post-climactic euphoria.It is held in many mental health circles that masturbation can relieve depression, stress and lead to a higher sense of self-worth (Hurlbert & Whittaker, 1991). Masturbation can also be particularly useful in relationships where one partner wants more sex than the other – in which case masturbation provides a balancing effect and thus a more harmonious relationship.
Mutual masturbation, the act by which two or more partners stimulate themselves in the presence of each other, allows a couple to reveal the "map to [their] pleasure centers". Witnessing a partner masturbate is an educational activity to find out the method a partner pleases him- or herself, allowing each partner to learn exactly how the other enjoys being touched.
In 2003, an Australian research team led by Graham Giles of The Cancer Council Australia concluded that frequent masturbation by males appears to help prevent the development of prostate cancer. The study also indicated that this would be more helpful than ejaculation through sexual intercourse because intercourse can transmit diseases that may increase the risk of cancer instead. Also, frequent ejaculation is more easily obtained and sustained over time with the aid of masturbation.
A study published in 1997 found an inverse association between death from coronary heart disease and frequency of orgasm even given the risk that myocardial ischaemia and myocardial infarction can be triggered by sexual activity. Excerpt, "The association between frequency or orgasm and all cause mortality was also examined using the midpoint of each response category recoded as number of orgasms per year. The age adjusted odds ratio for an increase of 100 orgasms per year was 0.64 (0.44 to 0.95)." That is, a difference between any two subjects appeared when one subject ejaculated at around two or more more times per week than the other. Assuming a broad range average of between 3 to 5 ejaculations per week for a healthy males, this would mean 5 to 7 ejaculations per week. This is consistent with a 2003 Australia article on the benefits against prostate cancer.
Masturbation is also seen as a sexual technique that protects individuals from the risk of contracting sexually transmitted diseases. Support for such a view, and for making it part of the American sex education curriculum, led to the dismissal of US Surgeon General Joycelyn Elders during the Clinton administration.
Sexual climax, from masturbation or otherwise, leaves one in a relaxed and contented state. This is frequently followed closely by drowsiness and sleep – particularly when one masturbates in bed.
Some people actually consider masturbation as a cardiovascular workout. And while doctors have no proof of this actually being true, those suffering from cardiovascular disorders (particularly those recovering from myocardial infarction, or heart attacks) should resume physical activity (including sexual intercourse and masturbation) gradually and with the frequency and rigor which their physical status will allow. This limitation can serve as encouragement to follow through with physical therapy sessions to help improve endurance.
Blood pressure
Both sex and masturbation lower blood pressure. A small study has shown that in one test group, recent full intercourse resulted in the lowest average blood pressure in stressful situations. Masturbation then led to lower blood pressure than did no recent sexual activity.
Insertion
Objects inserted into the vagina or anus should be clean and of a kind that will not scratch or break. Care should be taken not to fully insert anything into the anus – any object used should have a flared or flanged base; otherwise retrieval can require medical intervention. Modern dildos and anal plugs are designed with this feature.
Pregnancy
Masturbation involving both a man and a woman (see mutual masturbation) can result in pregnancy only if semen contacts the vulva. Masturbation with a partner can also theoretically result in transmission of sexually transmitted diseases by contact with bodily fluids.
Problems for males
A man whose penis has suffered a blunt trauma or injury during intercourse may rarely sustain a penile fracture or suffer from Peyronie's disease. Phimosis is "a contracted foreskin (that) may cause trouble by hurting when an attempt is made to pull the foreskin back". In these cases, any energetic manipulation of the penis can be problematic.
Lawrence I. Sank thought that masturbating prone (lying face downward) could be responsible for sexual problems in some men including anorgasmia and erectile dysfunction. He based this theory on four men he examined and coined the term traumatic masturbatory syndrome to describe it. As of 2007, no follow-up research has been conducted and the idea is not familiar or widely-held within the medical community. Some authors, however, continue to give it credence.
Compulsive masturbation
Masturbating frequently presents no physical, mental or emotional risk in itself,but masturbation can be used to relieve boredom or stress. In either case, as with any "nervous habit", it is more helpful to consider the causes of the boredom or of the stress, rather than try to repress the masturbation.
There is some discussion between professionals and other interested parties as to the existence or validity of sexual addictions. Nevertheless, there are lists of warning signs such as when sexual activity affects a person's ability to function in everyday life, or is placing them at risk, for example, of pursuing illegal or destructive activities. Very frequent and compulsive masturbation may be seen as a sign of sexual addiction.