Erectile dysfunction is a surprisingly common experience. It has been estimated that at least 1 in 10 men is affected to some extent yet, because of the embarrassment and even shame which has been attached to this condition, many men do not seek treatment. Growing older is a factor, with the number of those experiencing erectile dysfunction increasing with age, but it affects the entire range from the youngest to the oldest.
Erectile dysfunction is the inability to develop or maintain an erection that is rigid enough to allow penetration of the vagina, and therefore functional sexual intercourse. Generally, the term erectile dysfunction is applied if this occurs frequently (75% of the time) over a significant period if time (several weeks to months). If this is the case, the term impotence may also be used.
Performance anxiety can be another cause of impotence. If a person wasn’t able to achieve an erection in the past, he may fear he won’t be able to achieve an erection in the future. A person may also find he can’t achieve an erection with a certain partner. Someone with ED related to performance anxiety may be able to have full erections when masturbating or when sleeping, yet he isn’t able to maintain an erection during intercourse.
However, in contrast, a recent systematic review of published studies, the authors concluded that overall, the addition of testosterone to PDE-5 inhibitors might benefit patients with ED associated with testosterone levels of less than 300 ng/dL (10.4 nmol/L) who failed monotherapy.  A limitation of existing studies are their heterogeneous nature and methodological drawbacks.
There have been rare reports of priapism (prolonged and painful erections lasting more than six hours) with the use of PDE5 inhibitors such as sildenafil, vardenafil, and tadalafil. Patients with blood cell diseases such as sickle cell anemia, leukemia, and multiple myeloma have higher than normal risks of developing priapism. Untreated priapism can cause injury to the penis and lead to permanent impotence. Therefore, if your erection lasts four hours, you should seek emergency medical care.
It is estimated that up to 20 million American men frequently suffer from impotence and that it strikes up to half of all men between the ages of 40 and 70. Doctors used to think that most cases of impotence were psychological in origin, but they now recognize that, at least in older men, physical causes may play a primary role in 60% or more of all cases. In men over the age of 60, the leading cause is atherosclerosis, or narrowing of the arteries, which can restrict the flow of blood to the penis. Injury or disease of the connective tissue, such as Peyronie's disease, may prevent the corpora cavernosa from completely expanding. Damage to the nerves of the penis, from certain types of surgery or neurological conditions, such as Parkinson's disease or multiple sclerosis, may also cause impotence. Men with diabetes are especially at risk for impotence because of their high risk of both atherosclerosis and a nerve disease called diabetic neuropathy.
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).
The symptoms of erectile dysfunction include difficulty achieving an erection, trouble maintaining an erection, and a reduced interest in sex. Because male sexual arousal is a fairly complex process, it can sometimes be difficult to identify a specific cause. Arousal starts in the brain but it also involves the nerves, muscles, and blood vessels and can be impacted by hormones and emotions. If a problem develops with any of these things, erectile dysfunction could be the consequence.
How’s this for a win-win: The more sex you have, the less likely you are to suffer from erectile dysfunction, according to a 2008 study published in The American Journal of Medicine. Men aged 55-75 who reported having sex less than once per week had twice the incidence of erectile dysfunction (there were 79 cases of ED per 1,000) as men who have sex once a week (32 cases of ED per 1,000). But if you really want to up your odds, shoot for three times per week (only 16 cases of ED per 1,000). Can you really argue with science, or a perscription to have more sex?
Conditions that may be associated with ED include diabetes, [25, 26, 27] hypertension,  , and CAD, as well as neurologic disorders, endocrinopathies, benign prostatic hyperplasia,  , sleep apnea  , COPD,  and depression (see Table 1 below). [32, 33, 34, 35] In fact, almost any disease may affect erectile function by altering the nervous, vascular, or hormonal systems. Various diseases may produce changes in the smooth muscle tissue of the corpora cavernosa or influence the patient’s psychological mood and behavior.
While we may think the penis has a mind of it’s own, it’s actually heavily dependent to the brain, and too much stress can interfere with a man’s ability to obtain and hold an erection. According to Healthline, stress can interrupt how your brain sends messages to the penis to allow extra blood flow. Even though a man may want to have sex, too much stress can make this impossible.
#2 Physically exhausted. If you’ve been cranking it at the gym, haven’t been sleeping well, or you’ve been working your ass off at your job, getting tangled up with your lover for even more physically demanding activities may not sound ideal. Physical exhaustion has a direct effect on your ability to get aroused. The only fix for this one is to get some rest.
Penile blood flow is measured using a Doppler probe and a 2.5 cm blood pressure cuff. Systolic pressures in the right and left corpora cavernosa are measured and the penile–brachial index is calculated taking a ratio of penile systolic pressure to brachial systolic pressure. These measures should be repeated before and after 3 minutes of exercising the pelvic and leg muscles. In normal men, the PBI should be 0.9 or greater. Ratios between 0.7 and 0.9 suggest vascular impotence; a ratio below 0.6 is diagnostic. Pelvic arteriography can be done if revascularization is considered.
Certain types of blood pressure medications, antiulcer drugs, antihistamines, tranquilizers (especially before intercourse), antifungals (hetoconazole), antipsychotics, antianxiety drugs, and antidepressants, known as selective serotonin reuptake inhibitors (SSRIs, including Prozac and Paxil), can interfere with erectile function. Smoking, excessive alcohol consumption, and illicit drug use may also contribute. In rare cases, low levels of the male hormone testosterone may contribute to erectile failure. Finally, psychological factors, such as stress, guilt, or anxiety, may also play a role, even when the impotence is primarily due to organic causes.
Treatment. prostatitis or another acute infection affecting the genitalia can cause temporary impotence that clears up in response to antibiotics. The smooth muscle relaxant sildenafil (viagra) was introduced in 1998 as a treatment for organic impotence. Administration of testosterone may be indicated if low levels of this hormone are found in a blood sample. If impotence is organic and does not respond to other therapies, a penile prosthesis can be implanted; this is usually done surgically by a urologist. Other therapies include the use of vacuum tumescence devices and penile injection of pharmacologic agents that cause dilation.
Impotence can have emotional causes but most often it is due to a physical problem. The physical causes of impotence include diseases (such as diabetes and hypertension), injuries (such as from prostate surgery), side-effects of drugs (such as the protease inhibitors used in HIV therapy), and disorders (such as atherosclerosis) that impair blood flow in the penis. Impotence is treatable in all age groups. Treatments include psychotherapy, vacuum devices, surgery and, most often today, drug therapy.
The common PDE5 inhibitor drugs approved in the United States are sildenafil (Viagra), vardenafil (Levitra and Staxyn, the generic form), tadalafil (Cialis), or avanafil (Stendra). All of the currently approved PDE5 inhibitors work in the same way. They differ in the number of available doses, how quickly they work and last in your system, the dosing, and to some extent in the side effects. However, they generally share the same indications and contraindications. Currently, tadalafil is the only medication that patients can take on a daily basis and is approved for the treatment of both ED and BPH (benign enlargement of the prostate).
Prostaglandins (alprostadil): Alprostadil can be injected into the penis or inserted as a pellet through the urethra. It causes an erection without sexual stimulation that usually lasts about 60 minutes. The danger with this method is that too high a dose can cause priapism, an erection that won't go away. This condition requires immediate medical attention as it can cause serious bruising, bleeding, pain and permanent penile damage. Once the doctor is sure of the right dose, the man can self-inject at home.
Vacuum devices for ED, also called pumps, offer an alternative to medication. The penis is placed inside a cylinder. A pump draws air out of the cylinder, creating a partial vacuum around the penis. This causes it to fill with blood, leading to an erection. An elastic band worn around the base of the penis maintains the erection during intercourse.