Updated 11 June 2013

What’s up with morning glory?

Morning wood, early riser, breakfast boner, morning tent - whatever you call it - what's the story morning glory?

Morning wood, morning glory, early riser, breakfast boner, morning tent, whatever you call it, waking up with an erection after a refreshing night’s sleep is one of the more invigorating aspects of being a man. If you’ve ever worried that there’s something wrong with you, there is absolutely no cause for alarm – it happens to all healthy men who don’t suffer from physiological erectile dysfunction and is perfectly natural.

Here are a couple of interesting facts about morning glory which you may not have been aware of before:

  • the fancy medical jargon for a spontaneous erection during sleep is nocturnal penile tumescence;
  • it usually happens during periods of REM (rapid eye movement) sleep when the brain experiences heightened activity and vivid dreams occur, but it’s not actually related to having arousing or erotic dreams;
  • it typically happens three to five times a night and not just in the morning;
  • it happens to adults, boys and babies and is even observed in utero;
  • while it normally lasts for 20 to 30 minutes, it can persist for as long as two hours or more.

A test for impotence

Doctors may use the occurrence of nocturnal penile tumescence as a test for erectile dysfunction or impotence. The patient is asked to wear a small elastic computer device or, more simply, a band of perforated paper tape around his penis at night. Over a period of a few nights, this device can monitor changes in the girth of the penis while the man is asleep. If nocturnal penile tumescence is detected in a man who cannot achieve an erection while awake, his erectile dysfunction is probably the result of a psychological condition like sexual anxiety rather than having a physiological reason.


It might be said that having three to five “unused” hardons every night is a bit of waste. So what are the causes of nocturnal penile tumescence? Scientists aren’t certain, but have proposed a number of theories:

  • During an erection the penis’ corpora cavernosa are engorged by blood, resulting in increased tissue oxygenation, which in turn helps to prevent cavernous fibrosis, one of the most common causes of erectile dysfunction. The theory is that the brain stimulates the penis into regular sleep-time exercises to keep it well maintained and healthy. During REM sleep, the brain’s heightened activity causes various neurological signals and the release of hormones, including testosterone, which together may lead to an involuntary erection.
  • Nocturnal penile tumescence may be caused by a full bladder, which is known to cause mild stimulation of a region of the spinal cord which contains the nerves that control a man’s ability to have so-called reflex erections. While he’s awake, this mild stimulation is believed to be suppressed by various other distractions which are not present when he’s asleep.
  • Some researchers have suggested that morning wood can also be caused by a man’s bed partner arousing him in his sleep by making physical sexual advances.

Women have it easy

Now we all know that morning wood isn’t just all fun and games. It has its pros and cons – its ups and downs, you might say. The most taxing problem, of course, is the age-old challenge of urinating with an erection. If you haven’t managed to conquer this particular skill, you can find some humorous advice here. But be warned, this is not for the easily offended or faint-hearted and may not be safe for work!

(Andrew Luyt, Health24, November 2010)

(Picture: attractive man in bed from Shutterstock)


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