Morning wood has long been one of the strangest mysteries for men to figure out. And, for those who wonder why it happens, listen up, ’cause we’ve got the reason.

We all have our familiar morning routine, and, for whatever reason, having morning wood seems to be part of that daily activity. But, don’t be alarmed that something’s wrong with you because you’ve got an erection. In fact, it’s something you should embrace — and be happy about!

That’s right, guys, if you get morning wood on the reg, all that means is that things are looking healthy down there for you — which is always a good (and important) thing. But, why does morning wood occur? Well, we turned to some scientific stuff from our friends over at Men’s Health to help us answer that question.

According to the aforementioned Men’s Health piece, morning wood is actually caused from something that occurs in your mind during the day. That’s right, a hormone that hinders erections called noradrenaline is released while you’re out and about. But, when you fall asleep, the brain doesn’t release as much, which is why you have a boner in the morning.

Maybe more surprising, though, is that, per the Men’s Health piece, men actually experience three-to-five times per night — although you probably don’t know it. Talk about having some good wood, huh?

Naturally, another cause of morning wood is simply testosterone. More than likely, your levels of testosterone are highest in the morning, meaning your hormones are going pretty wild right as you roll out of bed and get ready to jump in the shower. Hey, it’s probably why you, ahem, “take care of yourself” in there.

Oh, and, per Men’s Health — who spoke with Tobias Köhler, M.D., M.P.H., who’s the associate professor and residency program director of the urology division at Southern Illinois University’s School of Medicine — morning wood is super important to keep your penis’ length. Nope, we’re not lying!

According to Köhler, regular nighttime erections keep the tissue on your penis soft and stretchy, which keeps your penile muscles smooth and relaxed, which helps the blood rush to it when you do get a boner. If this stretchiness decreases, there’s actually a chance that the size of your penis could shrink. How about that!?

So, there you have it, guys. Morning wood might have been something weird when we were younger, freaking us out as to why we got it. But, as it turns out, it’s pretty critical in good penis health — and now you have a reason to roll over and utilize that thing each morning, so drop some knowledge on whoever’s lying next to you.

(H/T Men’s Health)