What is actually happening

Nocturnal penile tumescence is a normal part of sleep architecture. During REM sleep, the sympathetic 'anti-erectile' outflow drops away while parasympathetic activity continues — so erections occur without any sexual content at all. Most men cycle through REM four or five times a night, and an erection accompanies each cycle. You simply happen to be awake for the last one.

The leading explanation for why this exists is tissue maintenance: regular oxygenated blood flow keeps the erectile tissue elastic. Erectile tissue that goes without it for long periods becomes fibrotic — which is the entire reasoning behind penile rehabilitation after prostate surgery.

Why clinicians ask about it first

It is the cleanest available separation of mechanism from psychology, because nobody has performance anxiety while asleep.

What your answer suggests
PatternWhat it points towardsWhere to look next
Regular morning erections, difficulty with a partnerThe machinery works. Psychological, relational or situational factors dominate.Performance anxiety, sex therapy
Gradual decline over years, alongside daytime difficultyVascular or metabolic disease progressing quietly.Cardiovascular, diabetes
Disappeared alongside low libido and fatigueHormonal — testosterone or prolactin.Low testosterone, thyroid and prolactin
Disappeared, and you snore heavily or wake unrefreshedFragmented REM sleep. Apnoea prevents the erections happening at all.Sleep apnoea
Stopped after a new medicationDrug effect.Medications that cause ED
Never had them reliably, young manWorth a full workup rather than reassurance.ED in younger men

How to observe this usefully

  • Track for two weeks, not one morning. Night-to-night variation is normal.
  • Note roughly how many mornings out of fourteen, and how firm — full, partial or absent.
  • Record alcohol, late meals and hours slept alongside it. All three suppress REM.
  • Note whether anything changed around the time they declined — a new medication, weight gain, a new stressor.
  • Take the tally to your appointment. It is more useful than trying to recall it in the room.

What changes normally with age

Frequency and rigidity both decline gradually with age, in step with falling testosterone and lighter sleep. Fewer per week in your sixties than in your twenties is expected.

What is not normal at any age is their complete disappearance. That is a change worth investigating rather than accepting — see is ED just part of getting older?

FAQ

Frequently asked questions

How often should I get morning erections?
Healthy men typically have three to five erections a night. How often you wake during one varies, and frequency declines gradually with age.
I have morning erections but problems with my partner. What does that mean?
It means the physical mechanism works, which points strongly towards psychological, relational or situational factors. That is genuinely good news, because those respond well to treatment.
Does losing them mean low testosterone?
It is one possibility, particularly alongside low libido and fatigue. Vascular disease and fragmented sleep from apnoea are at least as common and often overlooked.
Is the postage stamp test real?
It is folklore rather than a diagnostic test. It cannot distinguish an erection from ordinary movement in bed. Formal nocturnal tumescence testing exists but is rarely used now.
Sources

What this is based on

We link to primary sources — clinical guidelines, regulator publications and peer-reviewed research — wherever possible. Links open on third-party sites we do not control.

  1. [01]National Institute of Diabetes and Digestive and Kidney Diseases. Definition & Facts for Erectile Dysfunction.
  2. [02]Mayo Clinic. Erectile dysfunction — symptoms and causes.
  3. [03]Urology Care Foundation. What is Erectile Dysfunction?.
  4. [04]American Urological Association. Erectile Dysfunction: AUA Guideline (2018).