Meaning and causes of morning erections in men

Though it’s liable to turn your morning trip to the toilet into a contortionist act, morning wood also known as nocturnal penile tumescence, or the boner you roll out of bed with, is very much a good thing.

In fact, if you aren’t occasionally waking up with a stretched genital, it could mean you need to head to a doctor’s office to get your genital checked out. Waking up with a stretched genital in the morning, is actually one of the clearest signs of a healthy genital.

So vital is morning wood that urologists once diagnosed erectile problems by asking cisgender men to put a roll of stamps over their flaccid genitals before they went to bed. If the roll was broken in the morning, that meant the man in question was getting a stretched genital overnight, and thus had a healthy genital. (In 2021, urologists no longer recommend the stamp test.

There’s actually a portable home device you can purchase, called a RigiScan, which evaluates the strength of your nocturnal penile erections. Throughout the night, the machine repeatedly measures how much blood is in your genital and how much it can resist bending, getting a sense of how “hard” you are. The results are stored in the machine and are simple to share with your doctor.)

What causes morning wood?

According to Menshealth, the stretching of the genitals are cause by the stimulation of the parasympathetic nervous system. When you see, feel, hear and maybe even smell or taste something that is sexually attractive, it triggers the release of neurotransmitters.

This leads to the dilation of arteries in the genital, which means more blood flows into the genital, which means the genital becomes stretched. The parasympathetic system is more active when you’re sleeping, which in addition to producing stretched genital also causes your muscles to relax and your heart rate to slow.

Another reason you may wake up with morning wood is testosterone, which is likely to be at its highest level in the morning.