Why Do Men Wake Up With Erections In The Morning? Science Has The Answer!



“Ut oh. I thinks me gots the morning wood!”

Let’s take a few minutes and talk about BONERS. More specifically, the momentary crippler known as (and please say this in the gingivitis voice) “Morning Wood.”

Most of us have been there. (I’d normally say “we’ve all been there,” but I don’t want to make it weird for dudes suffering from hellacious dysfunction of their peen. I was raised to be courteous like that.) You wake up because your bladder is past the point of full. You’ve decided if you force sleeping any longer you might risk giving yourself a UTI and/or piss the bed. So you get up to go rectify the situation. That’s when you realize that although you’re groggy, your dick rose with the sun; its brimming with energy because its already on its second pot of coffee. Which sucks for you because now you’re stuck with the joy of trying to piss with the hard on of the century. We all know how fun that is.

So why does it happen? Why do penises insist on cycling between stiff and soggy while we sleep? The folks at I Fucking Love Science got to the bottom of it.

Nocturnal penile tumescence (NPT) actually starts in uteroor in the womb (seriously), and continues throughout life. If it’s any consolation, men aren’t completely alone—women also get clitoral erections and vaginal engorgement during sleep, and various nonhuman mammals also get NPT.

While a few different theories have been proposed over the years to explain NPT, what causes it still remains uncertain. NPT, just like clitoral erections, is associated with REM(rapid eye movement) sleep. One idea is that during REM sleep, noradrenergic cells(neurons that release the neurotransmitter noradrenaline [norepinephrine]) located in an area of the pons (part of the brainstem) called the locus coeruleus are switched off. It is thought that these cells are associated with the inhibitory tone of the penis; therefore, when their activity is reduced during REM sleep, testosterone-dependent excitatory tones can be expressed which result in an erection.

It’s also been suggested that NPT is triggered by the release of nitric oxide (NO). NO is released by cells that line the inside of blood vessels which then diffuses into smooth muscle, causing it to relax. This also causes blood vessels to dilate, hence increasing blood flow to the penis and voila, an erection. It’s thought that increased activity of part of the pons during REM sleep triggers a cascade of events that ultimately lead to NO release by nerve fibers. This is also regulated by androgens such as testosterone.

Anyone else kind of drift off to another place after reading the words (and please also say this in the gingivitis voice) “VAGINAL ENGORGEMENT?”


Just me?

Fine. Assholes. If you want to keep reading about why morning wood is a thing, head on over to I Fucking Love Science. I’ll join you once I can stop thinking about clitoral erections and the crotch disease known as…ok, I’ll stop.

[Image via ShutterStock]