Three reasons why 'morning glory' exists, according to science

Ah, nocturnal penile tumescence, the common thing most of you with a penis have likely experienced.

Yeah, super sexy name that isn’t it? We all know it better as ‘morning glory’ which is confusing as well because that’s also the name of a veg used in a lot of Thai cooking – but let’s not get into that.

The phenomena happens pretty often and surprisingly, it apparently occurs about three to five times during an eight-hour stint of sleep. And it turns out if you do wake up with an erection it’s not necessarily because of some wild dream you were having but because your junk is healthy.

There’s three reasons why morning glory happens according to science - and the first is down to the sleep cycle.

What's the story, morning glory? (Getty Stock)

Sleep Cycle

Sergio Diez Alvarez, director of medicine at The Maitland and Kurri Kurri Hospital and the University of Newcastle, explained in a post on The Conversation in 2016: "Nocturnal penile erections occur during Rapid Eye Movement (REM) sleep (the phase during which we dream. They occur when certain areas of the brain are activated."

He added: "Sleep is made up of several cycles of REM and non-REM (deep) sleep. During REM sleep, there is a shift in the dominant system that’s activated.

"We move from sympathetic (fight and flight) stimulation to parasympathetic (rest and digest) stimulation."

The medical expert said that this shift in balance drives a response from the parasympathetic nerve system - and this causes that tent to get pitched.

Testosterone Levels

"Testosterone, which is at its highest level in the morning, has also been shown to enhance the frequency of nocturnal erections," Alvarez added.

"Interestingly, testosterone has not been found to greatly impact visual erotic stimuli or fantasy-induced erections. These are predominantly driven by the 'reward system' of the brain which secretes dopamine."

No, not that kind of tent. (Getty Stock)

Nature Calls

Last but definitely not least, some professionals think it could just be the body's way of letting you know you need to pee - which would explain why the glory’s over when the bladder’s empty

"It’s more likely the reason for the morning erection is that the unconscious sensation of the full bladder stimulates nerves that go to the spine and these respond directly by generating an erection (a spinal reflex)." added Alvarez.

While scientific studies haven't fully concluded that nocturnal penile tumescences contribute to the health of a person's bits, some studies have suggested that if they stop abruptly, it could be a marker of diseases such as diabetes which impact erectile function, or severe depression.

Most of the time it's nothing to worry about, but if you notice any changes with those sturdy wake-up calls or you're concerned, it's always best to seek the advice of your GP or a medical professional.