Why Men Wake Up with an Erection

Many physiological factors are believed to interact in causing morning erections. They are not believed to be caused directly by sexual arousal, though sexual arousal can certainly happen in the morning. A lack of morning erections can be a sign of erectile dysfunction, a condition that can be successfully treated in most men with prescription medications.


Erections are a normal part of every man’s sexual health, and they occur for various reasons. Sexual arousal is the most common cause of erections, but prostate stimulation can also cause an erection, even if no direct sexual stimulation is involved. In fact, men can randomly get erections throughout the day for seemingly no reason at all. However, there is one type of erection that mystifies both men and women: the morning erection, sometimes colloquially referred to as “morning wood”.

Common Myths About Morning Erections

One of the biggest misunderstandings regarding erections upon waking is that they are caused by the need to urinate. Men should know, but for women and for men who don’t understand how the penis works, it doesn’t become erect when urine is flowing through the urethra. In fact, the urge to urinate has very little to do with the urethra at all. The pressure felt when one needs to urinate is coming from the bladder, not the penis.

And, again, as mentioned, during urination, the penis does not get erect. In fact, for men, it can be incredibly difficult to urinate with an erect penis. As such, an additional theory is that the penis becomes erect during sleep in order to keep a man from urinating during the night, but there are many other processes within the body that regulate urination during sleep that this doesn’t seem plausible.

Another myth about morning erections is that a man is sexually aroused. It’s certainly possible, but a morning erection does not directly correlate to being turned on. This misconception can actually cause trouble in relationships when a man has an erection, is not in the mood, but his wife believes that he is. She tries to make a move, he rejects her, and then feelings are hurt. She’s thinking that, because he has an erection, he’s automatically ready to have sex, but this is not necessarily the case.

In addition to that, some people believe that morning erections are the result of sexual dreams prior to waking. While this can be true, and while men do get erections throughout the night, sexual dreams are not directly correlated to morning erections. In fact, sexual dreams may not result in an erection at all as the body and brain have a somewhat disconnected relationship during this time.

So What Does Cause Erections Upon Waking?

According to an article in Cosmopolitan Magazine, there really isn’t much that science has that conclusively gives a singular reason for erections upon waking. This is partly due to a lack of studying the subject, but it’s also because of the complex nature of sexual health in general.

The reproductive organs of both men and women are complicated enough, but the related hormones, emotions, and mental components make things even more difficult to understand. All of these things play into why erections occur in the first place, and because a man is sleeping when the erection occurs, he can’t exactly tell a scientist what was going on at the moment.

REM Sleep and Erections

One theory is that, during REM sleep, certain parts of the brain shut down, meaning the penis, and other parts of the body, are acting on their own. This has been theorized due to a study by the Society of Endocrinology that showed how active different parts of the brain act during different times and types of sleep.

It’s already well-known that the body twitches, jerks, rolls around, and the mouth makes audible noises during sleep, and some people even sleepwalk. In fact, to a larger point, the body can even get up, prepare meals, eat, drive, and do all kinds of other activities during sleep with the person having no recollection of these activities upon wakes. As such, it makes sense that the penis can also “have a mind of its own” during sleep and prior to waking.

What About Those Hormones?

Elevated testosterone levels in the morning are one factor in producing morning erections.


As mentioned previously, hormones play a complicated part in how and when erections occur. Testosterone is the hormone in men that is responsible for certain manly characteristics, such as increased muscle mass and body hair. It is also responsible for regulating things like libido. As such, it’s believed that testosterone levels in men are higher in the morning, thus causing erections just prior to waking.

With this stated, people are different. Some become more sexually interested during the morning while others become more sexually interested in the afternoon or evening. Still others wake up in the middle of the night with sexual urges. Therefore, it can’t be said with certainty that this is the cause.

As men age, most experience a drop in testosterone production, and this typically means that men also experience fewer morning erections. However, newer drug therapies are assisting men in raising testosterone levels, even as they age, and when taking such medications, men may continue to experience erections upon waking.

The Penis May Be Being Conditioned to Become Erect

Another theory is that the penis may become erect as a matter of conditioning. In a sense, the penis needs to be able to stay erect for various lengths of time, up to an hour. During sleep, it may accept more blood to become erect in order to stay functional. If the penis did not receive blood often and become erect, it may lose its ability to do so over time. So, morning erections may be an unconscious bodily function through which the penis is being conditioned to continue to operate as usual.

Sexual Stimulation During Sleep May Be the Culprit

Earlier, it was mentioned that men don’t need sexual stimulation to achieve and erection, and just because a man wakes up with an erection doesn’t necessarily mean that he is sexually aroused. However, the case may be that he was rubbing against his wife during sleep, and even though not conscious of the fact, the brain may be sending signals to the penis to become erect. Basically, the body is on autopilot and is reacting automatically to stimuli. Once again, the man may not be sexually aroused, but the brain says, “Hey … what do we usually do when we feel this sensation?” and an erection occurs.

Nocturnal Emissions May Play a Part

Nocturnal emissions are occurrences of nighttime ejaculation. This phenomenon happens to virtually all men, especially when they are younger. Basically, the male body produces semen, and when that semen is not ejaculated, either through sex or masturbation, the body expels it. This happens during sleep because the body and brain are not in coordinated communication. In almost all cases, ejaculation cannot happen when the penis is flaccid, so an erection is required in order to achieve a nocturnal emission. If a nocturnal emission happens just prior to waking up, or if it is about to happen just prior to waking up, then a man may have an erection in the morning.

Waking Up Without an Erection

It’s also important to note that not all men wake up with an erection, and for those that do, it is not an every morning occurrence. Morning erections generally happen younger in life, but they can dwindle with time. As pointed out, decreasing testosterone levels can affect morning erections with age, and other factors, such as stress, poor diet, and lack of sleep can also be to blame. Likewise, certain medications, such as antidepressants, have been known to inhibit libido and affect hormones, thereby diminishing the chances for an erection upon waking.

Are You Experiencing Fewer Erections?

If you’re experiencing fewer erections, or if you’re unable to achieve an erection at all, you may be suffering from a condition known as erectile dysfunction. This condition can be caused by low testosterone and again. Stress can also be a factor. You may also notice a lessened sex drive. In such cases, it would be a good idea to speak with your doctor to discuss your symptoms and any relevant conditions in your life that may be causing your symptoms.

In some cases, lifestyle adjustments, such as cutting back on alcohol consumption or losing weight may help, while in others, medications, such as Viagra, can assist you in achieving an erection. Viagra is a prescription medication that works as a short-acting vascular stimulator, promoting healthy blood flow to the penis.

Discuss the Issue With Your Partner and Your Doctor

Many men who cannot achieve an erection, even after direct sexual stimulation, often feel embarrassed and distraught. This can then lead to complications in their marriages as communication shuts down. One of the most important things you can do in such a situation is to talk to your wife about how you’re feeling. You need to also be receptive to how she is feeling about your love life. Many times, talking about how both of you feel can help to relieve anxiety and associated depression. Additionally, don’t hesitate to speak with your doctor about erection health. They’re there to help you, after all, and there is no reason to be embarrassed, because erection issues are a fact of life for millions of men. And remember, there are many effective solutions available, so don’t give up!

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Don Amerman has spent more than three decades in the business of writing and editing. During the last 15 years, his focus has been on freelance writing. For almost all of his writing, He has done all of his own research, both online and off, including telephone and face-to-face interviews where possible. Don Amerman on Google+