How the penis works

The penis is just a collection of specialized blood vessels within a tough outer sheath of connective tissue. Sexual arousal causes blood to flow into the penis by releasing NO (Nitric Oxide) from the nerves supplying the penile arteries. The blood then fills a series of blood sacks called sinusoids allowing the spongy tissue to become engorged. As the engorged tissue presses against the outer fibrous sheath, the veins normally allowing blood to freely drain from the penis become narrowed. This traps the blood in the penis and helps to maintain the erection. Continued sexual arousal keeps the penile arteries widely dilated, allowing the head of pressure within the circulation to keep the penis erect. NO produced in the tissue lining these arteries and sinusoids keeps the smooth muscle around them relaxed so that maximum distention and rigidity occurs.
Thus there are five things you can do to improve your erectile function:

1. Use the relaxation response to prevent the effects of stress from constricting the inflow of blood (see stress and EF)
2. Work with your partner to maximize sexual arousal (see for sexual partners). This keeps the penile arteries widely dilated by causing release of NO from nerve endings supplying those arteries.
3. Maximize NO production by the nerves and the tissue lining the penile vessels through all of the lifestyle, dietary changes and supplements we are recommending (see Survival of the firmest™ and supplements for erectile health).
4. Condition your circulation. Through exercise, your heart will be able to respond to the demands of sex with enough left over to fill the penis under a good head of pressure (high blood pressure won’t help you- high blood pressure occurs because of constriction of blood vessels, not the dilation that you need to fill the penile tissues). See exercise and EF. This is a “three-fer”. Not only does conditioning allow your circulation to pump more blood into the penis, exercise itself causes blood vessels to produce more NO through the shear forces resulting from the more rapid blood flow, and exercise also increases the sensitivity of your tissues to insulin (insulin stimulates NO).
5. If the above measures are not sufficient (realize it may take a few weeks to have an effect and the effects appear to build over time), you can try a very low dose (see precaution under our recommended supplements) of Viagra, or its longer-acting relatives, Cialis and Levitra. These drugs act by increasing cyclic GMP by inhibiting the enzyme, phosphodiesterase 5, that normally breaks it down. However, this is a very artificial way of producing an erection, and the drugs have side effects and rare serious complications. They do nothing to solve the underlying problem of poor vascular function due to inadequate NO production.

    

See, it’s not so hard to understand how it gets hard!