OK, But... Why Do Men Get 'Morning Wood'?

Let’s set the scene. It’s early — you’re still sleeping, in fact, when you feel something poking you from your partner’s side of the bed (who needs an alarm clock when you have a boner in your back?). Or maybe you’ve just woken up, and through your sleep-fogged eyes, you notice the Leaning Tower of Penis beneath your bedmate’s covers. Either way, you’ve grown accustomed to seeing an erection before you’ve even gotten your first cup of coffee. And while there are many people who would just go on about their day and never wonder why wieners are predictably early risers, I’m not one of those people. I wanted to know: Why do men get “morning wood”?

Since going straight to the source wasn’t getting me anywhere (fine, it was getting me *somewhere*, just not somewhere with answers), I reached out to an actual medical expert to clue us all into the mechanics of this common peen, ahem, phenomenon. As it turns out, there’s some pretty interesting science involved.

So, why does this happen?

If you assumed the reason for a.m. erections revolves around dirty dreams, guess again. Well, that could have something to do with it. However, the more likely scenario has to do with something surprisingly un-spicy: the sleep cycle.

“Morning erections, known medically as nocturnal penile tumescence, are a natural and healthy physiological response,” Dr. Justin Houman, a board-certified urologist, men's health specialist, and assistant professor of urology at Cedars-Sinai Medical Center, tells Scary Mommy. “They occur during REM (rapid eye movement) sleep, a stage when brain activity increases and testosterone levels reach their peak. During REM, the body temporarily reduces the influence of neurotransmitters that usually suppress erections while awake, allowing spontaneous erections to occur.”

That’s the science-driven data for you. It’s worth noting, though, that while not medically proven, per se, it’s entirely possible for your partner to get a nocturnal erection from physical touch. After all, he’s asleep — not dead. If you happen to rub up against him (intentionally or otherwise), his body may respond even if he’s still snoozing away.

Why are early morning erections so common?

It’s typically just a matter of timing.

Explains Houman, “Since REM sleep happens in cycles throughout the night and tends to be more frequent in the early morning hours, it’s common for a man to wake up during or shortly after one of these cycles — often while an erection is still present. These erections are not necessarily related to sexual arousal or dreams. Instead, they serve an important biological purpose: helping to maintain healthy erectile tissue by ensuring regular oxygen-rich blood flow to the penis.”

REMs gonna REM, amirite?

Not only can these erections be quite frequent (around three to five times per night), but they can linger: Studies show they typically stick around for 10 to 25 minutes and may stretch upwards of 50 minutes or longer.

Are morning erections ever something to be worried about?

Fortunately, morning wood generally isn’t anything to worry about. Quite the opposite.

“They are typically a sign of healthy nerve function, adequate blood flow, and balanced hormone levels — especially testosterone. Regular morning erections can be a reassuring indicator that the body’s erectile mechanisms are functioning properly,” reassures Houman.

On the other hand, if your partner is young and healthy and not experiencing semi-routine morning wood, it might be time to make an appointment with their doctor. “A noticeable decrease or absence of morning erections, particularly in younger men, may be a signal of hormonal imbalances, vascular issues, or sleep disturbances that warrant medical evaluation.”

So, there you have it. Morning wood, or nocturnal penile tumescence if we’re using its full government name, is pretty routine. And while it may disrupt your sleep, it’s likely just a byproduct of your partner’s.