The average man has about 11 erections each day and several more at night.

But these erections don’t always happen because a man is sexually excited. Sometimes, there is no sexual stimulus at all.

For example, many men wake up with an erection. These morning erections are usually the last of a series of 3 to 5 erections that happen during the night (nocturnal penile tumescence). Each erection usually lasts for about 25 – 35 minutes.

Nighttime erections often happen during REM sleep, when a man is dreaming. It isn’t clear why they happen. Some researchers think nighttime erections are a way to preserve elastic penile tissues. Doctors can use information about nighttime erections to diagnose erectile dysfunction (ED).

Another type of non-sexual erection is the reflex erection, which can happen when a man is nervous, scared, angry, or under stress. Reflex erections can also be caused by an enlarged prostate condition, some recreational drugs, and the need to urinate.

Reflex erections are more common in a man’s teenage and young adult years. Many adolescents worry about getting erections at the “wrong” time, but reflex erections are a normal part of growing up. As men get older, the frequency of reflex erections tends to decrease.