It’s an amusing, albeit often highly inconvenient, phenomenon that half of the world’s population has to deal with on a regular basis. So what’s the science story behind that morning glory? Let’s find out.
Morning glories, or nocturnal penile tumescence (NPT) as they are correctly called, are spontaneous erections that occur during sleep or while waking up. All blokes without erectile dysfunction are graced with them and they normally occur around three to five times during sleep.
NPT actually starts in utero, or 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 non-human mammals also get NPT, according to iflscience.com
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.
What Causes Morning Wood?
According to healthline.com the cause of NPT is likely multifactorial. Doctors have a few theories that help explain why men wake up with an erect penis from time to time, but none of these theories are supported by concrete, medical evidence. These theories include:
Though your eyes are shut, your body is still very much aware of what’s happening around you. If you or your partner accidentally touch or graze your genitals, you may become erect. Your body senses the stimulation and responds with an erection.
Your testosterone level is at its highest in the morning after you wake up. It is highest immediately after waking up from rapid eye movement (REM) sleep stage. The increase in this hormone alone may be enough to cause an erection, even in the absence of any physical stimulation. As men get older, usually between ages 40 and 50, natural testosterone levels begin to fall. As this level decreases, episodes of NPT may decrease as well.
During your waking hours, your body releases hormones to suppress erections. When you’re asleep, your body releases less of those hormones. Combine this fact with the other reasons you may experience an erection in your sleep, and NPT becomes more likely.
What’s clearer is what doesn’t cause morning wood. For example, needing to urinate isn’t responsible for morning wood. Some people believe a morning erection keeps them from urinating during their sleep, but this is not true. Morning wood also isn’t always a sign of sexual stimulation. In many cases, NPT isn’t caused by dreams or thoughts of a sexual nature.
Who Gets Morning Wood?
Men of all ages can experience NPT. It’s healthy at any age and is a sign of a properly functioning blood and nervous system in and around the penis. Young boys may experience NPT as young as 6 to 8 years old. NPT may also occur in men in their 60s and 70s. It will become less frequent as ED issues begin to occur, and those issues become more frequent with age.
Men may experience an erection three to five times each night. Unrelated to what’s in your dreams, NPT can last up to and even longer than 30 minutes. Some men may experience an erection as long as two hours during their sleep. Most erections will ease within a few minutes of waking up.
Having an erect penis when you wake is an indicator of healthy blood and nerve supply to the penis. The presence of NPT also likely indicates that you’re physically capable of getting and maintaining an erection while awake.
If you stop experiencing NPT or notice that you’re not waking up with an erect penis anymore, this may be an early sign of an underlying medical problem.
Most likely, this is a sign of physical erectile dysfunction (ED). You may have something happening within your body that’s preventing adequate blood or nerve supply for proper erectile function. You may be more likely to experience ED if you:
- are overweight
- have high blood pressure
- have high cholesterol levels
- have diabetes
- have depression
Certain physical disabilities may also make ED more likely.
Medications may also affect your ability to experience morning wood. Painkillers and some antidepressant medications may prevent NPT.
NPT may become less common as you get older, but if you’re young and are not experiencing a morning erection or if your erections suddenly stop, it may be time to see your doctor.
When To See A Doctor
Morning wood is healthy, and it’s rarely a reason to see your doctor. However, two situations may mean it’s time to make an appointment. These include:
You Stop Having Morning Wood
If you frequently experienced morning wood but now aren’t experiencing it at all or have fewer erections, you should talk with your doctor. While it’s natural for episodes of NPT to occur less frequently with age, a sudden drop in frequency may be a sign of an underlying medical problem.
You Begin Experiencing Painful Erections
Most morning erections will subside within 30 minutes of waking up. If your erections last more than hour after you wake up or if they become painful, you should make an appointment to see your doctor.
It’s hard to declare “too much” and “too little” when it comes to NPT. Some men experience a morning erection every day. Some experience is less than once a week. During your annual physical exam, talk with your doctor about how frequently you’re experiencing morning wood. If you’re not experiencing it enough, your doctor may be able to help diagnose a reason.