Blood Flow
The arteries in the penis normally relax and widen when a man becomes sexually aroused. This allows more blood flow into the penis. The penis expands and veins that usually carry blood out of the penis become compressed and restrict blood flow. This produces an erection. Viagra mimics this process to help a man, who has difficulty obtaining and keeping an erection, have an erection when sexually aroused. The erection goes away when the sexual encounter is completed, explains Big Health, a health website. Viagra is for men with erectile dysfunction and can be used to control and increase blood flow to the penis for sexual functioning during a certain period after it is taken.
Sexual Arousal
Viagra, like other drugs for male sexual enhancement, increases levels of nitric oxide, a chemical produced by the body during sexual stimulation, according to the Mayo Clinic. This is what helps a man achieve and maintain an erection. But Viagra does not automatically bring a man an erection. It is not an aphrodisiac. The man must be sexually aroused and want to have a sexual encounter. In other words, he has to be in the mood for sex. Sometimes men taking sexual enhancement medication expect miracles to happen immediately. Sexual arousal is necessary to begin the process. Viagra helps by providing the penis with more blood flow for stronger erections the man once experienced naturally.
Not for Everyone
Viagra is usually taken in tablet form once a day without food. It may take 20 to 60 minutes to work and may last for up to four hours. There may be side effects that are mild and brief, including headaches and facial flushing. It is considered safe for most men, but not everyone. Because Viagra reduces blood pressure a bit, which is not a problem for most men, it can be dangerous for men who are using nitrates, often prescribed for angina or chest pain. This could increase a drop in blood pressure that might be fatal. The Mayo Clinic points out that it might not be wise to take Viagra if you have heart problems, heart pain during sex, heart rhythm problems, high or low blood pressure, a history of stroke within the last six months, or if you suffer from sickle cell anemia, leukemia or other conditions that produce erections that won't subside.
Other Benefits
But Viagra may also have unexpected benefits for people with particular heart conditions because of its ability to increase blood flow. Research in 2007 at the University of Alberta, Canada, reported in Circulation, the journal of the American Heart Association, found that Viagra might increase heart performance and save a person's life when that patient has problems with the function of the right ventricle of the heart.
