Night-time Erections: Your Body’s Built-in Health Check
To assess the plausibility, we should first understand what nocturnal erections (also known as nocturnal penile tumescence, (NPT) represent physiologically, and what mechanisms underlie their loss.
In healthy men, spontaneous erections occur during sleep, especially during REM (rapid eye movement) phases, typically 3 to 5 times per night, often lasting 20–30 minutes or more per episode.
Because these occur largely independent of conscious sexual stimulation, psychological/arousal factors are minimised, and thus they are often considered a “baseline test” of whether the neuromuscular / vascular machinery is intact.
The mechanisms involve coordination of neural impulses, intact penile blood vessel function, endothelial release of vasodilators (e.g. nitric oxide), and structural integrity of penile tissues. Any impairment in these systems (nerve damage, endothelial dysfunction, vascular disease) can diminish or abolish nocturnal erections.
In other words, NPT is an “internal stress test” of penile vascular health. Loss of NPT suggests a more fundamental physiologic dysfunction (vascular, neural) rather than purely psychogenic or situational erectile issues.
Thus, if nocturnal erections are lost (or severely attenuated), that may reflect early vascular or systemic pathology (e.g. endothelial dysfunction) that also affects other organs, including coronary arteries and cerebral vessels.
Erectile dysfunction, NPT loss, and cardiovascular disease: what the evidence shows
When it comes to data, much of the literature addresses erectile dysfunction (ED) in general rather than narrowly “loss of nocturnal erections.” But some studies specifically use NPT testing or other objective metrics as markers of organic vascular ED, and correlate them with vascular risk.
Here are the key strands of evidence:
1. ED as a predictor of cardiovascular disease
This is the broader, more solidly supported link. Numerous observational studies have found that men with erectile dysfunction have a higher incidence of future cardiovascular events (myocardial infarction, stroke, cardiovascular death) compared to men without ED, even after adjusting for traditional risk factors.
A review in Circulation describes ED as a “sentinel marker” of cardiovascular risk, often preceding overt coronary disease by 2–5 years.
In a meta-analysis and clinical reviews, erectile dysfunction has been consistently associated with higher rates of coronary artery disease, heart failure, and vascular mortality.
For example, in a U.S. cohort (average age ~69, no prior heart disease), men reporting ED had a ~6.3% incidence of cardiovascular events (heart attack, stroke or death) over ~4 years vs ~2.6% in men without ED (More than double the rate)!
Another analysis shows that the presence of ED is associated with a ~2× increased risk of heart attack, stroke or cardiovascular death beyond standard risk factors.
In European cardiology guidance, ED is recognized as an “independent risk factor” and sexual function is recommended to be included in cardiovascular risk assessment.
So in broad strokes: men with ED are significantly more likely than those without to suffer a cardiovascular event.
2. Evidence using nocturnal penile tumescence / objective measurements
These are fewer, but more directly relevant to your question about “loss of nocturnal erections.”
A study titled “Objective tests to diagnose erectile dysfunction” used NPTR (nocturnal penile tumorence) testing and found that abnormal NPTR results, combined with cardiovascular risk factors, may signal vascular erectile dysfunction and generalized vasculopathy (i.e. systemic vascular disease).
Another study comparing patients with “abnormal NPTR” vs “normal NPTR” found that those with abnormal NPTR had worse penile blood flow (“peak systolic velocity”) and a higher prevalence of cardiovascular risk factors (hypertension, diabetes, older age) — suggesting that NPTR abnormalities correlate with subclinical vascular impairment.
Though sample sizes are modest and results are nuanced, these findings support the hypothesis that absence or impairment of nocturnal erections is not just a symptom but a marker correlated with vascular dysfunction.
We were unable to locate large‐scale prospective cohort studies that start with men who have lost nocturnal erections (versus ED in general) and track how many go on to have cardiovascular or stroke events.
3. Estimating “how many men with erectile dysfunction have a significant cardiovascular or stroke event”
Because of the overlap, one commonly used proxy is: “What proportion of men with ED go on to have heart attack, stroke or cardiovascular death?” Using that, we can infer a rough magnitude (with caveats):
In the U.S. cohort mentioned earlier: ~6.3% of men with ED had a heart attack, cardiac arrest, or stroke / death over ~4 years, versus ~2.6% in men without ED.
In other words: among men with ED, the risk in a few years is on the order of 5–7% for a major cardiovascular event (in that older cohort) under observation.
Some studies suggest the relative risk is about 2× higher compared to men without ED.
Thus, in a population of men with ED (including loss of nocturnal erections), a nontrivial fraction (several percent over a multi-year period) will have a cardiovascular or cerebrovascular event.
But it's important to highlight:
The absolute risk depends heavily on baseline cardiovascular risk factors (age, hypertension, diabetes, smoking, cholesterol, etc.). A younger, low-risk man with ED may have much lower absolute risk than older men with multiple comorbidities.
Most studies use self-reported ED rather than objective nocturnal erection data; thus the precise risk for men with only NPT loss is less well characterized.
Putting it all together: how strong is the link, and how big is the risk?
Here’s a summary:
Biological plausibility is strong: nocturnal erections require intact vascular, endothelial and neural systems. Loss of these erections suggests that pathology may already be affecting blood vessels systemically.
Erectile dysfunction (more generally) is a well-established risk marker for cardiovascular disease and stroke. The time interval from onset of ED to a cardiovascular event is often 2–5 years, giving clinicians an opportunity for early intervention.
Men with ED tend to have ~2× the risk of cardiovascular events compared to those without, and in some cohorts, ~5–7% of men with ED experienced a major vascular event over ~4 years in older populations.
Direct prospective data on men who specifically lose nocturnal erections (versus general ED) is lacking. But some smaller studies using NPT testing show that abnormal NPTR correlates with markers of vascular disease and risk factors.
Thus, although we cannot definitively say “X% of men who lose nocturnal erections will have a stroke or heart attack,” the evidence suggests that loss of nocturnal erections is a red flag that should prompt cardiovascular evaluation, because a meaningful minority of such men are at elevated risk in coming years.
Caveats, limitations, and gaps in knowledge
Causality: These are observational associations. Loss of nocturnal erections (or ED) may reflect underlying vascular disease, but may not independently cause it. Confounding by shared risk factors is a challenge.
Heterogeneity: Not all ED is vascular. Some ED is neurogenic, hormonal, psychological or medication-related. Similarly, nocturnal erections can be suppressed by sleep disorders, depression, medications, and other nonvascular factors.
Age effect: Nocturnal erection frequency declines with age naturally, even in healthy men. So absence of NPT in older men may be partly normative.
Lack of large prospective NPT-based cohorts: Most large-scale vascular risk studies categorise men by ED symptoms, not by NPT measurements.
Absolute risk varies greatly: A man of 45 with no vascular risk factors and isolated NPT loss likely has much lower risk than a 65-year-old hypertensive diabetic man with ED.
Clinical and public health implications & recommendations
Given the evidence, the following principles are reasonable (though each individual should consult a physician):
Men who notice loss of morning erections or absence of nocturnal erections (especially if persistent) should not dismiss it as merely “normal aging” - it may be an early sign of vascular dysfunction.
Such men should be evaluated for cardiovascular risk factors: blood pressure, lipids, glucose/HbA1c, smoking history, body mass index, diet/exercise, etc.
Physicians (urologists, general practitioners, cardiologists) should regard ED (or NPT loss) as a sentinel symptom and consider more proactive vascular screening and management.
Interventions that improve vascular health (exercise, diet, smoking cessation, statins, blood pressure control, TRT, weight loss medication) may slow or reverse endothelial dysfunction and reduce risk.
More research is needed: ideally, prospective studies beginning with men with impaired NPT (but not yet manifest heart disease) and tracking cardiovascular and stroke outcomes over time.
Why It Matters to Valens Health
At Valens Health, we take a whole-body approach to men’s health - because testosterone, metabolism, heart health, and cognitive function are all connected.
When a patient reports reduced morning or nocturnal erections, we don’t simply prescribe — we investigate. Our clinicians explore the root causes through comprehensive blood testing, assessing cardiovascular, metabolic, and hormonal markers to uncover whether the issue is hormonal, vascular, or neurological.
From there, our team develops individualised treatment plans that may include:
Testosterone or metabolic optimisation (where clinically indicated)
Lifestyle and cardiovascular risk management
GLP-1 therapies for weight and insulin regulation
Erectile function support using safe, evidence-based protocols
Our goal is not only to restore function but also to prevent long-term vascular complications - protecting the heart, brain, and hormonal health simultaneously.
In Summary
Loss of nocturnal erections is not merely a sexual issue - it is often related to a cardiovascular symptom that deserves serious attention.
By identifying and addressing these changes early, men can take control of their long-term health, reduce their risk of cardiac and cerebrovascular disease, and regain confidence in both body and mind.