Typically, men can have between three and five erections while sleeping at night. These erections are not painful and are not a cause for concern. They are also not sexually-stimulated.

However, men with sleep-related painful erections (SRPEs) often wake up with an aching erection that may last for up to an hour. SRPEs can occur multiple times during the night and lead to sleep deprivation, daytime fatigue, anxiety, and irritability. 

Men with SRPEs usually don’t have painful erections during sex. In fact, they often have normal sexual function.

SRPEs are uncommon and have not been widely researched. Studies have had mixed results, making SRPEs a challenge to treat.

Scientists aren’t sure why SRPEs occur. They do not appear to be related to particular health conditions, sexual dysfunction, or testosterone levels. Some research suggests that hypertonia (weakness and tightness) of the pelvic floor muscles might be involved.

Because little is known about their origin, SRPEs can be difficult to treat. For some men, getting out of bed, urinating, or walking around brings relief. Stress management may also help.

In a 2017 study, scientists reported that treatment with the muscle relaxant baclofen improved symptoms for a short time for some men, but not always for the long term. They added that pelvic floor physical therapy might be worth trying, but more research is needed.

Men who find they wake up with painful erections should discuss their situation with their urologist.