Although not proven, it is likely that erectile dysfunction can be prevented by good general health, paying particular attention to body weight, exercise, and cigarette smoking. For example, heart disease and diabetes are problems that can cause erectile dysfunction, and both are preventable through lifestyle changes such as sensible eating and regular exercise. Furthermore, early diagnosis and treatment of associated conditions like diabetes, hypertension and high cholesterol may prevent or delay erectile dysfunction, or stop the erectile dysfunction from getting more serious.
Stiffy Solution: Again, saying "stop being so stressed out so you can get boners again" is easier said than done — but a lot of people find sexual dysfunction to be a stronger motivator to live a healthier lifestyle than the threat of, say, a heart attack down the road; so there's a chance that this could actually be a good thing in the long run for your boo, if it helps him take his stress seriously. Relaxation techniques like yoga, exercise, meditation, tai chi, and getting adequate sleep can all lessen the impact of stress on your body (and your dong).
Cavallini, G., Modenini, F., Vitali, G., & Koverech, A. (2005, November). Acetyl-L-carnitine plus propionyl-L-carnitine improve efficacy of sildenafil in treatment of erectile dysfunction after bilateral nerve-sparing radical retropubic prostatectomy. Urology, 66(5), 1080-5. Retrieved from http://www.sciencedirect.com/science/article/pii/S0090429505006515
In comparison, 37% of men who had received external radiotherapy as their primary therapy reported the ability to attain functional erections suitable for intercourse, along with 43% of men who had received brachytherapy as primary treatment. Pretreatment sexual health-related quality of life score, age, serum prostate-specific antigen (PSA) level, race or ethnicity, body mass index, and intended treatment details were associated with functional erections 2 years after treatment. 
There are no formal tests to diagnose erectile dysfunction. Some blood tests are generally done to exclude underlying disease, such as hypogonadism and prolactinoma. Impotence is also related to generally poor physical health, poor dietary habits, obesity, and most specifically cardiovascular disease such as coronary artery disease and peripheral vascular disease. Therefore, a thorough physical examination is helpful, in particular the simple search for a previously undetected groin hernia since it can affect sexual functions in men and is easily curable.
Between 10 and 88% of patients diagnosed with cancer experience sexual problems following diagnosis and treatment. The prevalence varies according to the location and type of cancer, and the treatment modalities used. Sexuality may be affected by chemotherapy, alterations in body image due to weight change, hair loss or surgical disfigurement, hormonal changes, and cancer treatments that directly affect the pelvic region.
The 1985 National Ambulatory Medical Care Survey indicated that there were about 525,000 visits for erectile dysfunction, accounting for 0.2 percent of all male ambulatory care visits. Estimates of visits per 1,000 population increased from about 1.5 for the age group 25-34 to 15.0 for those age 65 and above. The 1985 National Hospital Discharge Survey estimated that more than 30,000 hospital admissions were for erectile dysfunction.
Willful and capricious – erections are funny things. When you're a young man, they seem to pop up at the most inappropriate moments (and the only thing between you and embarrassment is a carefully placed notebook). As you get older, however, they go the other way, and fail to appear on demand no matter how much you try. The sad thing is, my patients often equate this with a loss of masculinity.
A good indicator that "everything is in working order" and that it is probably a psychological cause is if a “morning erection” is still experienced. Feelings like fear, anger, distress and anxiety cause part of the nervous system to come into play which directly blocks the action of another part of the system involved in creating an erection. This is a natural reaction – our ancestors would find it more difficult to run from a predator with an erection in the way!
All NOS subtypes produce NO, but each may play a different biologic role in various tissues. nNOS and eNOS are considered constitutive forms because they share biochemical features: They are calcium-dependent, they require calmodulin and reduced nicotinamide adenine dinucleotide phosphate for catalytic activity, and they are competitively inhibited by arginine derivatives. nNOS is involved in the regulation of neurotransmission, and eNOS is involved in the regulation of blood flow.
A lot of guys don’t want to admit it, but not being able to get or keep an erection happens more often than you’d think. Guys usually have trouble getting or keeping an erection when they’re nervous, scared or worried about something. They might be worried about how they’ll “perform,” or they could be feeling guilty about having sex. They might be afraid of getting a sexually transmitted disease (STD), or, if they are with a girl, getting their partner pregnant. Drugs (including some anti-depressants) and alcohol can also prevent you from getting and/or maintaining an erection.
Despite the accumulation of a substantial body of scientific information about erectile dysfunction, large segments of the public -- as well as the health professions -- remain relatively uninformed, or -- even worse -- misinformed, about much of what is known. This lack of information, added to a pervasive reluctance of physicians to deal candidly with sexual matters, has resulted in patients being denied the benefits of treatment for their sexual concerns. Although they might wish doctors would ask them questions about their sexual lives, patients, for their part, are too often inhibited from initiating such discussions themselves. Improving both public and professional knowledge about erectile dysfunction will serve to remove those barriers and will foster more open communication and more effective treatment of this condition.
Penile erection is managed by two mechanisms: the reflex erection, which is achieved by directly touching the penile shaft, and the psychogenic erection, which is achieved by erotic or emotional stimuli. The former uses the peripheral nerves and the lower parts of the spinal cord, whereas the latter uses the limbic system of the brain. In both cases, an intact neural system is required for a successful and complete erection. Stimulation of the penile shaft by the nervous system leads to the secretion of nitric oxide (NO), which causes the relaxation of smooth muscles of corpora cavernosa (the main erectile tissue of penis), and subsequently penile erection. Additionally, adequate levels of testosterone (produced by the testes) and an intact pituitary gland are required for the development of a healthy erectile system. As can be understood from the mechanisms of a normal erection, impotence may develop due to hormonal deficiency, disorders of the neural system, lack of adequate penile blood supply or psychological problems. Spinal cord injury causes sexual dysfunction including ED. Restriction of blood flow can arise from impaired endothelial function due to the usual causes associated with coronary artery disease, but can also be caused by prolonged exposure to bright light.
ED may occur with or without other sexual dysfunction, including decreased libido (decreased interest in sexual activity), orgasmic dysfunction (troubles achieving an orgasm/climax), and ejaculatory dysfunction (problems with the fluid released during sex, including lack of ejaculation [anejaculation], small volume ejaculate, ejaculation that occurs too quickly [premature ejaculation], ejaculate that goes backward into the bladder [retrograde ejaculation] and pain with ejaculation).
While pills for ED are convenient, some men sustain stronger erections by injecting medication directly into the penis. Drugs approved for this purpose work by widening the blood vessels, causing the penis to become engorged with blood. Another option is inserting a medicated pellet into the urethra. The pellet can trigger an erection within 10 minutes.