REM sleep: Men have dreams during rem sleep (generally ~ 4 cycles per night) and will have erections due to increase blood flow, during rem sleep regardless of age. For a 21yr, the rem sleep is longer & frequently younger men will wake up with an erection.
Answered 5/15/2013
5.2k views
2 doctors weighed in across 2 answers
90,000 U.S. doctors in 147 specialties are here to answer your questions or offer you advice, prescriptions, and more.
Ask your question