Tag Archives: sleep cycle

Science behind the Morning Wood

It happens to grown men, little boys, and even male still in utero: the ability to pitch a tent in the morning in your pyjamas without any camping skills.

All jokes aside, nocturnal penile tumescence, otherwise known as morning wood, is a phenomenon that males experience on a daily basis without a full understanding of how and why it happens.

An experience we men are too familiar with

It is revealed by studies that morning wood occurs numerously during sleep, and is in direct correlation with the sleep cycle that alternates between levels of sleep.

One of the most important stages of sleep is the Rapid Eye Movement (REM) stage. An average male undergoes REM stage around 4-8 times over regular sleep, and at this stage of sleep certain neurotransmitters decrease.

Of the many neurotransmitters that decrease during REM sleep, Norepinephrine is one of them.

Norepinephrine structure

Norepinephrine acts as a vasoconstrictor that regulates erections. Metaphorically, it is used as a stop sign chemical that inhibits blood flow into penis muscles and thus inhibiting the erection.

In REM sleep, it is proved that norepinephrine levels drastically drop and allow vasodilation, increasing the blood flow into the penile muscles.

So why is morning wood important?

To answer the question, increased blood flow into the penis muscles, like any other tissue in the body, increases oxygenation. This increased blood flow and oxygenation is critical in repairing and maintaining functionality.

Another question one might bring up is why we always wake up to this phenomena. The answer is because we most usually wake up just out of REM sleep and thus observe the remnants of this sleep stage.

It is profound how such phenomena we face everyday without much thought can be the result of chemical reactions in the male body. Perhaps next time you wake up with morning wood you’ll be assured that you’re fully repaired and fully functional.