"The penis is a bundle of blood vessels."
I say this to patients in clinic because it is the most accurate and most useful reframe I can offer. Not a mystery. Not a symbol. A bundle of vessels — arteries, smooth muscle, endothelium — governed by the same biology as every other vascular bed in the body, and subject to the same diseases.
What goes wrong in most cases of erectile dysfunction is not simply poor blood flow. The precise term is endothelial dysfunction — and understanding it changes how you think about both your erection and your heart.
What is endothelial dysfunction
The endothelium is the single-cell-thick lining of every blood vessel in your body. It is not passive scaffolding — it is metabolically active tissue that produces nitric oxide, the molecule that triggers erection. Nitric oxide causes the smooth muscle in arterial walls to relax. When that happens in the penis, arteries dilate, blood floods the erectile chambers, and the resulting pressure produces rigidity.
Think of the endothelium as the control layer. When it works, erections work. When it is damaged, the signal fails.
When the endothelium is damaged — by high blood pressure, high cholesterol, elevated blood sugar, smoking, or chronic inflammation — nitric oxide production falls. Dilation is impaired, and the mechanism fails. The same endothelial damage, in larger vessels, is what causes heart attacks. Penile arteries are 1–2mm in diameter. Coronary arteries are 3–4mm. Atherosclerosis affects the smaller vessels first — which is why erectile dysfunction caused by vascular disease typically appears two to five years before cardiac symptoms develop.
What erectile dysfunction actually is
Myth
ED is a problem of the penis.
Fact
ED is usually a problem of the endothelium — the lining of blood vessels throughout the body. The penis is where the problem shows up first, because its arteries are smaller. The disease is systemic.
Myth
It must be psychological — there is nothing physical to investigate.
Fact
Even when anxiety is a prominent driver, an organic workup is still indicated. Stress and vascular disease coexist and reinforce each other. Saying it is probably stress is not a complete assessment.
What the evidence shows
The link between erectile dysfunction and cardiovascular disease is one of the most replicated findings in modern andrology. Men with ED have significantly higher rates of cardiovascular events than men without it — and the pattern holds across multiple large studies.
The numbers
ED and cardiovascular risk
+44%
Increased rate of major cardiovascular events in men with ED compared to men without
+62%
Higher risk of myocardial infarction
+39%
Higher risk of stroke
The Princeton IV Consensus (2024) formally designates erectile dysfunction as an ASCVD risk-enhancing factor — placing it in the same clinical bracket as a family history of premature coronary artery disease. QRISK3, the cardiovascular risk calculator used as standard in UK primary care, is the first major risk tool to formally include ED as an independent variable. If your GP is calculating your ten-year cardiovascular risk without asking about your erections, the calculation is incomplete.
What this means for you
If you have erectile dysfunction and you are over 40, a cardiovascular assessment is not optional — it is part of the workup. Not because ED always means heart disease, but because it is a signal that deserves proper investigation.
What a cardiovascular risk assessment actually involves
When you come to see me about your erections, I do a basic cardiovascular assessment as part of the initial workup. It is not an elaborate investigation — it is the same assessment a well-prepared GP should do.
Is your cardiovascular picture complete?
A short self-assessment to identify gaps in your cardiovascular workup before your first appointment. Interactive tool coming shortly.
Measured in clinic after five minutes of rest. Hypertension (above 140/90 mmHg) is the single most prevalent modifiable risk factor in men with ED, and it is frequently undiagnosed. High blood pressure damages the endothelium through mechanical shear stress — the same process that causes atherosclerosis. I cannot responsibly write a prescription without knowing this number.
Resting heart rate above 80–100 bpm may indicate deconditioning, thyroid pathology, or arrhythmia. In the context of an ED assessment, irregularity warrants further cardiac evaluation before advising on sexual activity or prescribing.
Waist circumference above 102 cm in men is more clinically meaningful than BMI — it is a marker of central adiposity, which drives insulin resistance, raises oestrogen relative to testosterone, promotes systemic inflammation, and worsens endothelial function through multiple pathways. I measure both.
Glycated haemoglobin reflects average blood glucose over the preceding three months. A result of 48 mmol/mol or above confirms diabetes; 42–47 indicates pre-diabetes. Both are significant. I see men in their 40s who have never had their glucose checked. An elevated HbA1c in a man who came in about his erections is not a peripheral finding — it is the diagnosis that was waiting to be made.
Total cholesterol, LDL, HDL, and triglycerides. Elevated LDL drives atherosclerotic plaque formation. Low HDL is an independent risk marker. Elevated triglycerides suggest insulin resistance and metabolic syndrome.
Fasting, between 07:00 and 11:00. Testosterone deficiency coexists with vascular ED more commonly than recognised, particularly in men with metabolic syndrome, obesity, or diabetes. Low testosterone worsens endothelial function and reduces nitric oxide production — and reduces libido in ways that are easy to conflate with the erection problem itself.
When I refer for a stress test
An exercise tolerance test (ETT) is not part of a routine ED workup. It is a specialist investigation, arranged through cardiology, reserved for specific clinical situations. The principle is straightforward: sexual activity is roughly equivalent to walking briskly up two flights of stairs — around three to five metabolic equivalents. A man whose heart cannot sustain that level of exertion safely cannot safely have sex. The stress test establishes whether that threshold is met.
During an ETT, the patient walks on a treadmill or cycles on an exercise bike while connected to an ECG monitor. The workload increases gradually. We are looking for ischaemic changes on the ECG, significant arrhythmias triggered by exercise, abnormal blood pressure responses, and the point at which symptoms develop. For men who cannot exercise, a pharmacological stress test simulates the cardiac effects of exertion.
Video: sex is equivalent to climbing two flights of stairs
Mr Ollandini explains what this means clinically — and why the question for men with cardiac history is always about exercise tolerance, not drug safety. Coming soon on @urotubeggo.
When I refer to cardiology
Exertional symptoms — chest pain, breathlessness, syncope — not yet investigated. Exercise tolerance genuinely uncertain and sexual activity needs safety clearance. Multiple uncontrolled risk factors with high QRISK3, where coronary artery calcium scoring may be appropriate. Clinical suspicion of unstable or high-grade coronary disease.
This is a minority of patients. Most men with ED and cardiovascular risk factors can be assessed and managed without a cardiology referral.
The medication problem: what the package insert doesn't tell you
When a medication is licensed, manufacturers must report any event occurring at higher rates in trial participants than in the placebo group — regardless of whether the medication caused it. For antihypertensives, antidepressants, and antipsychotics, this creates a specific problem: the conditions these drugs treat are themselves causes of erectile dysfunction.
To know definitively whether it is the drug or the disease, you would need a randomised trial in which half the patients with hypertension received no treatment. That trial is not ethical to run. The honest clinical position is: it depends on the drug, and in many cases we genuinely do not know the relative contribution of drug versus disease. What we can do is reason about mechanism, look at comparative data between drug classes, and make a clinical judgement.
Three categories matter here. First: drugs where the disease is almost certainly the primary driver — ACE inhibitors, calcium channel blockers, ARBs. They appear on the package insert because the law requires any trial signal to be reported, not because the drug is the problem. Second: drugs where there is plausible direct pharmacological effect plus disease confounding — beta-blockers, thiazide diuretics, SSRIs, SNRIs, antipsychotics. Third: drugs with predominantly iatrogenic effect — opioids (HPG axis suppression, measurably low testosterone) and finasteride/dutasteride (post-finasteride syndrome signal under active EMA regulatory review).
Three categories
Medications and erectile dysfunction
Disease is the driver
ACE inhibitors, ARBs, calcium channel blockers. The underlying hypertension causes ED — not the drug treating it. Do not stop these without speaking to your prescriber.
Drug + disease overlap
Beta-blockers, thiazide diuretics, SSRIs, SNRIs, antipsychotics. Plausible direct effect plus disease confounding. The choice of agent within the class often matters.
Predominantly drug-caused
Opioids (measurably suppress testosterone) and finasteride/dutasteride (post-finasteride syndrome under EMA review). These warrant honest clinical disclosure.
Among the safest antihypertensive class in terms of erectile function. Some evidence of modest positive effect as blood pressure normalises. If your ED appeared around the time amlodipine was prescribed, the more likely explanation is that your blood pressure was elevated enough to require treatment — the disease, not the drug, is the likely driver. The cardinal rule: do not stop a cardiovascular medication without discussing it with the prescribing doctor.
Similarly favourable profile. ACE inhibitors may improve endothelial function through bradykinin pathways. The evidence does not support them as a primary cause of ED in most patients. The same confounding logic applies: hypertension drives endothelial damage; the drug treats it.
More plausible direct effect. Non-selective beta-blockers reduce cardiac output and peripheral blood flow through a mechanism that could plausibly affect erection quality. Nebivolol — a newer, selective beta-blocker — stimulates nitric oxide release and appears to have a neutral-to-positive effect on erectile function. If beta-blockers are clinically indicated, the choice of agent matters.
The most consistently associated antihypertensive class with erectile dysfunction in comparative studies. Mechanism debated — possibly zinc depletion affecting testosterone, or haemodynamic effects. If this is the only antihypertensive a patient is taking and ED is a significant concern, discussing an alternative with the prescribing doctor is reasonable. Do not stop without that conversation.
Well-documented direct sexual side effects — primarily delayed ejaculation, but ED is reported meaningfully. Mechanism involves reduced dopaminergic activity, elevated prolactin, and possibly serotonin-mediated testosterone effects. Depression itself impairs arousal and reduces desire. Post-SSRI sexual dysfunction (PSSD), where symptoms persist after discontinuation, is a recognised signal with evolving regulatory attention. Bupropion and mirtazapine are generally better tolerated sexually. This is a conversation for the prescribing doctor, not a reason to stop medication independently.
Several agents — particularly older typicals and risperidone — raise prolactin significantly, suppressing testosterone through HPG axis effects. This is pharmacologically mediated and measurable. Quetiapine and aripiprazole have lower prolactin-raising potential. If antipsychotic-related sexual dysfunction is suspected, a prolactin measurement is a useful starting point. Changes to antipsychotic prescribing require psychiatric involvement.
Long-term opioid use causes measurable suppression of the HPG axis. Testosterone falls — sometimes dramatically — in a dose-dependent relationship. This is the most clearly iatrogenic mechanism on this list. If you are on long-term opioids and have ED and reduced libido, a morning testosterone is essential. Low testosterone in this context is almost certainly opioid-induced hypogonadism — and it is treatable, though dose reduction is the ideal first step where clinically possible.
5-alpha-reductase inhibitors reduce conversion of testosterone to dihydrotestosterone. Sexual side effects are reported at low rates in licensing trials (1–3%), but post-marketing data has raised questions about persistent sexual dysfunction after discontinuation — post-finasteride syndrome (PFS), currently under active EMA regulatory review. The mechanism is debated; the signal is real enough to warrant honest disclosure. If you are taking finasteride for hair loss and have noticed a change in erection quality, it is worth raising clinically.
PDE5 inhibitors and the heart: clearing up the myth
Viagra and the heart
Myth
Viagra is dangerous for the heart.
Fact
PDE5 inhibitors are not cardiotoxic. The safety signal that generated the warning was a drug-drug interaction with nitrates — not evidence that the drug harms cardiac muscle. For men not taking nitrates, the cardiovascular safety record is excellent.
Myth
If you have had a heart attack, you cannot take Viagra.
Fact
A prior myocardial infarction is not a contraindication to PDE5 inhibitors. The question is whether the heart has recovered sufficiently to sustain the metabolic demands of sexual activity — not whether the drug is toxic. A man who has recovered well from an MI and can climb two flights of stairs without symptoms can, in most cases, safely use a PDE5 inhibitor.
Myth
Viagra dangerously lowers blood pressure.
Fact
At standard doses, PDE5 inhibitors reduce systolic blood pressure by approximately 5–8 mmHg — a clinically insignificant effect for most men. The dangerous hypotension occurred only when PDE5 inhibitors were combined with nitrates — two drugs acting on the same molecular pathway simultaneously.
In 1998, when sildenafil was first approved, several men who combined it with nitrate medications — GTN spray, isosorbide mononitrate, drugs prescribed for angina — developed severe and sometimes fatal drops in blood pressure. The regulatory response was a prominent warning. That warning was widely, and understandably, misread as: this drug harms the heart.
It does not. The mechanism was a pharmacodynamic interaction, not cardiac toxicity. Nitrates and PDE5 inhibitors both act on the nitric oxide/cGMP/smooth muscle pathway. Combined, they amplify vasodilation to a degree that can overwhelm haemodynamic compensation. Remove the nitrate, and the risk disappears entirely.
For men with heart failure or cardiac disease, the question is not whether PDE5 inhibitors are toxic — they are not. The question is whether the physical activity of sex is safe for this patient's heart. Those are completely different clinical questions.
PDE5 inhibitors relax blood vessels and lower the load on the heart. There is good biological reason to think this should help the heart rather than harm it. A 2024 meta-analysis pooled sixteen cohort studies covering around 1.26 million men. It reported lower rates of major cardiac events and lower all-cause mortality in men taking PDE5 inhibitors, compared with non-users (Soulaidopoulos et al., Eur Heart J Cardiovasc Pharmacother 2024). The data are observational. Confounding is possible — men who get a PDE5 prescription are often men whose cardiovascular care is already supervised more closely. The signal is real; the cause is uncertain. I would not sell PDE5 inhibitors as heart protection. The honest version: used properly, they are safe in stable heart disease. They may be helpful as a side effect. They are not a replacement for proper cardiovascular care.
The real contraindications — specific and limited
Concurrent nitrate medication in any form — prescribed or recreational. Prescribed forms include glyceryl trinitrate (GTN) sprays, isosorbide mononitrate or dinitrate, and patches worn on the skin. Recreational forms include amyl nitrite — commonly known as poppers — and any other "nitrite" inhalant. The combination can cause severe, sometimes fatal, drops in blood pressure. Concurrent nicorandil. This is a UK drug used to treat angina (chest pain from poor blood supply to the heart). It also releases nitric oxide, so the same rule applies. Concurrent riociguat (a drug for some types of high blood pressure in the lungs). Severe liver problems. A recent stroke or heart attack, before the heart has been reassessed. Very low resting blood pressure (below 90/50 mmHg). Non-arteritic anterior ischaemic optic neuropathy (NAION) — a rare eye problem of the optic nerve. If none of these apply, and a proper assessment has been done, the heart-safety concern is almost certainly not real.
The 44-Year-Old Whose Erection Saved His Heart
Cardiovascular risk stratification for sexual activity and PDE5 inhibitors
Princeton III Consensus — Nehra et al., Journal of Sexual Medicine, 2012.
Risk tiers
Low risk — safe to proceed
Controlled hypertension · Mild stable angina · Successful revascularisation · Uncomplicated prior MI (>6–8 weeks) · Mild valvulopathy · CHF NYHA Class I · ≤2 additional CAD risk factors
Intermediate risk — cardiac assessment first
≥3 CAD risk factors · Moderate stable angina · Recent MI (2–6 weeks) · CHF NYHA Class II · Non-cardiac sequelae of atherosclerosis (stroke, PVD)
High risk — stabilise first
Unstable or refractory angina · Uncontrolled hypertension · CHF NYHA III–IV · MI or CVA <2 weeks · High-risk arrhythmias · Obstructive HCM · Moderate–severe valvulopathy
What happens in my clinic
When a man comes to see me about his erections, what I am really doing is assessing his vascular health through the window the erection has opened. The erection is the entry point. What I find behind it — blood pressure, glucose, lipids, testosterone, lifestyle factors — is often more clinically significant than the erection problem itself.
Most of the time, the workup reveals something manageable. Occasionally, it reveals something that needed finding. Either way, the erection did its job. It got the man into a room where the right questions were asked.
Ready to understand what is actually happening?
A single consultation maps the erection problem and the cardiovascular picture together. You will not be handed a prescription and shown the door.
No. ED has many causes — psychogenic, hormonal, medication-related, and vascular. Most men with ED do not have significant cardiovascular disease. But it is a signal that warrants proper investigation, particularly in men over 40 with any cardiovascular risk factors.
No. Never stop a cardiovascular medication without discussing it with the prescribing doctor. The underlying hypertension is far more likely to be driving your erection problem than the medication treating it. If there is a genuine concern, the conversation is about which agent, not whether to treat.
In some cases, meaningfully yes — particularly when the endothelial damage is early and risk factors are well managed. Men who quit smoking, achieve significant weight loss, or bring diabetes and blood pressure under control often report genuine improvement. With established structural vascular disease, improvement is partial but the cardiovascular benefit is independent.
It depends on the nature of your heart disease and whether you take nitrates. If your condition is stable, your exercise tolerance is adequate, and you do not use nitrates in any form, PDE5 inhibitors are almost certainly safe for you. A proper assessment — which I do as part of any ED workup — establishes this clearly.
QRISK3 is the cardiovascular risk calculator used as standard in UK primary care to estimate your ten-year risk of a heart attack or stroke. It is the first major risk tool to formally include erectile dysfunction as an independent variable. If your GP is calculating your QRISK3 without asking about your erections, they are running an incomplete calculation.
Yes — and you do not need to be confrontational about it. A request for baseline blood tests (glucose, lipids, testosterone, blood pressure) is entirely reasonable and is what national guidelines recommend for any man presenting with new ED. If this has not been offered, a specialist consultation is the appropriate next step.
Erectile dysfunction — the full overview
Causes, investigation, and treatment options across the full spectrum.
Venous leak — symptoms, diagnosis and treatment
When the problem is structural. How penile Doppler maps the vascular picture.
Testosterone deficiency and TRT
How testosterone deficiency overlaps with cardiovascular ED and how to diagnose it properly.
Can't get hard with a partner?
When the pattern points toward psychogenic drivers rather than vascular disease.
One number deserves a separate mention. The Olmsted County study (Inman et al., Mayo Clinic Proceedings 2009) followed 1,402 men aged 40–79 for ten years. In men aged 40–49 with ED, the rate of new coronary artery disease was about fifty times higher than in men of the same age without ED. That figure is real, and it is dramatic. But it sits on a low absolute baseline. The prevalence of ED in 40–49-year-olds in the cohort was only 2%. The absolute rate of new coronary events in younger men in either group is small. Read the figure as a strong relative signal: in a younger man, ED is a reason to start the vascular conversation now. It is not a forecast of a heart attack next year.
Sleep is part of the cardiovascular conversation
One investigation does not appear in the standard list above, but increasingly belongs there: a check for obstructive sleep apnoea (OSA). OSA is a condition where the airway repeatedly closes during sleep. This causes oxygen levels to fall and blood pressure to spike. It is more common than most men realise. And it is bad for the blood vessels in its own right. A 2018 systematic review of twenty-eight studies looked at the link. Between 40% and 80% of men with OSA also had ED, depending on severity (Kellesarian et al., Int J Impot Res 2018). Continuous positive airway pressure (CPAP) — the standard OSA treatment — improves erectile function modestly but consistently in randomised trials. The cardiovascular benefits of treating OSA are independent.
If you snore heavily, wake with morning headaches, fall asleep during the day, or your partner has noticed you stop breathing in your sleep — say so. A short questionnaire (the STOP-Bang) and a home sleep study can settle the question.
Lifestyle is the first treatment, not the optional one
The treatments that improve your erections in the long term are the same ones that improve your life expectancy. The list is uncomfortable but short. Stop smoking. Lose excess weight. Exercise regularly. Eat a Mediterranean-style diet. Treat any sleep apnoea. Keep your blood pressure, cholesterol and blood sugar under control. Each item has clinical-trial evidence behind it. EAU and BSSM guidelines recommend all of them.
The strongest single trial in this space is Esposito's 2004 study, published in JAMA. It randomised 110 obese men with ED — none had diabetes or hypertension at baseline — to one of two groups. The intervention group got a structured diet plus exercise programme. The control group got standard advice. After two years, the IIEF score in the intervention group rose from 13.9 to 17.0. The control group barely moved. Around one-third of the intervention group regained normal erectile function (IIEF ≥22). The mechanism was endothelial. Inflammatory markers (like C-reactive protein) improved alongside the IIEF score (Esposito et al., JAMA 2004).
Smoking cessation deserves a separate sentence. The vascular damage from smoking is partly reversible. Men whose ED is short-standing and who stop smoking can see real improvement within weeks to months. Men with long-standing severe ED and decades of smoking can see partial improvement, sometimes incomplete. I will be honest with you about that. There is no honest version of "stop smoking and your erections will be perfect again". There is an honest version: stop smoking, your erections will probably be better than they would otherwise be, and you will live longer.
A note on blood pressure tablets. Older beta-blockers (propranolol, atenolol) and high-dose thiazide diuretics carry the worst record for erectile side effects. ACE inhibitors and ARBs are neutral or slightly favourable. Calcium-channel blockers are roughly neutral. Nebivolol is the beta-blocker with the most favourable erectile profile. Do not stop or switch any cardiovascular medication on your own. Bring it up with the prescribing GP or cardiologist. If two equivalent agents are on the table, erectile function can be one factor in the choice.
The things I will not say
A few honest negatives. Promising too much is a reliable way for clinical care to disappoint.
I will not say that every man with ED is heading for a cardiac event. The link is real but not fixed — it depends on age, pattern, and other risk factors. Many younger men with situational ED and preserved morning erections have no real cardiovascular concern in the short term.
I will not say that "if Viagra works, your heart is fine". A response to Viagra means the chemistry of erection still works once it is boosted. It does not rule out coronary disease, high blood pressure, diabetes or metabolic syndrome.
I will not say that lifestyle change reverses every case of ED. It improves a meaningful share. It does not cure all of them, particularly in men with long-standing severe disease.
I will not say that shockwave therapy fixes the cardiovascular cause of ED. It can produce small short-term gains in erectile function for some men. It does not treat coronary or peripheral vascular disease.
And I will not say that buying ED tablets online without a health review is enough. It is not. It treats a symptom while leaving a possible disease unaddressed.
A note on online ED tablets — and why it matters more in 2026. The MHRA's enforcement work continues to find counterfeit Viagra-style tablets sold through unregulated marketplaces. In April 2026 alone, the MHRA worked with eBay to remove around 215 listings of unauthorised ED medicines from the platform. The tablets seized cannot be tested for what they actually contain. They may have no sildenafil at all, an unsafe excess of it, or contaminants. Buying ED medication from a UK-registered online pharmacy with the green-cross logo is reasonable. Buying from social media, messaging apps, or unfamiliar websites is not.