What Your Erection Reveals About Longevity
Psst. Come closer. Closer!
Okay, maybe not that close. This isn’t that kind of article… unless your idea of foreplay includes biomarkers, testosterone rhythms, and a cheeky chat about cardiac health. Then yes, it might exactly be that kind of article. Because I’m about to slip into a nurse’s uniform and talk about sex, health, hormones, and all the intimate signals your body sends long before the doctor will see you. Which, inevitably, brings me to my favorite man on this subject: Bryan Johnson.
You’ve probably heard me mention him a couple of times before: the millionaire biohacker with a longevity protocol stricter than his own bedtime (which, for the record, is earlier than most toddlers). You’ve likely rolled your eyes, questioned his sanity, or wondered whether he’s proof you really can out‑supplement death. But here’s the thing: amid all the blood swaps and enemas, Johnson has opened a way more provocative conversation: erections. He hasn’t pioneered science in any formal, peer-reviewed sense. But he’s quantified what most people ignore: strapping sensors to his best friend, logging nightly erections as dutifully as earnings reports, and even comparing metrics with his teenage son. According to his own data, his nocturnal erections now rival those of a healthy 22-year-old. Is it science? Is it Silicon Valley performance art? Possibly both. But it raises a compelling question: what if sexual health — including the subtle signals your body sends during arousal, anticipation, and even sleep — is a far more powerful biomarker than we’ve been trained to believe? Johnson’s nocturnal data might sound like biohacker self-parody, until we realise it’s measuring what scientists are starting to take seriously. Because here’s the punchline modern medicine often misses: what goes up may be trying to warn you about what’s going down.
Your Heart Wants You to Have More Sex
In fact, a 2024 study of around 17,000 U.S. adults (Teng et al.) documented a striking relationship between sexual frequency, cardiovascular disease (CVD), and mortality. Sexual acts, in their model, referred to partnered sexual activity, not strictly orgasms. The findings were eye-opening: people reporting fewer than 12 sexual acts per year had significantly higher rates of both CVD and all-cause mortality. As frequency increased, risk steadily declined, bottoming out somewhere between 52 and 103 acts per year. That’s once or twice a week, for those doing the math with slightly more enthusiasm. Beyond that, benefits plateaued, and in some subgroups, even reversed slightly. So yes, it’s technically possible, albeit rare, to go too hard on the cardio. A 2025 follow‑up cohort (Davis et al.) confirmed the pattern that low sexual frequency plus pre‑existing heart disease produced worse outcomes than heart disease alone. In other words: skipping sex when your heart is already vulnerable might be a double whammy.
Why? Because sexual arousal isn’t just a romantic notion, but rather tiny stress tests for your body. And each time blood rushes to the pelvic area, it confirms that the vascular system is functioning. It has been confirmed that men who are sexually active in midlife tend to have better cardiovascular health, and better cardiovascular health improves sexual performance — a literal feedback loop. That’s because arousal triggers a whole series of helpful changes in the body: it releases nitric oxide, which relaxes smooth muscle and increases blood flow. Your heart rate goes up, which boosts circulation, while muscle contractions help to keep your metabolism active. And thanks to vasodilation (the widening of blood vessels) your body delivers oxygen more efficiently throughout the system. So put simply, if you’re paging Dr. Feelgood and he isn’t showing up, the problem might not be psychological, but vascular. And as Jackson et al. noted, decreased sexual activity is not just a consequence of cardiovascular decline, but can also be a predictor. Some doctors even argue that erectile issues often show up 3 to 5 years before more obvious cardiac events. So when your body starts saying I can’t get it up, it’s not necessarily about age, attraction, or the second Negroni, but your cardiovascular system filing an early withdrawal notice.
Of course, as every intro-to-statistics course will remind you, correlation isn’t causation. Just because people who have more sex live longer doesn’t mean sex is the sole reason that they do. Healthier people may simply be more capable (and more likely) to be sexually active. It’s also possible that sexual frequency tracks with other variables like relationship satisfaction, emotional well-being, or even access to healthcare. But here’s the clincher: researchers in both studies controlled for age, BMI, smoking, chronic illness, and mental health — and the link between low sexual frequency and increased cardiovascular risk still held significantly, especially among people with preexisting heart conditions. So while we can’t say with certainty that sex extends your life, the evidence strongly suggests it acts as both signal and stimulus. Translated: If your body can’t handle sex, that’s a red flag, but if your body can, sex might be part of the reason it stays that way.
The 24‑Hour Hormone Cycle
Let’s get one thing straight: while women run on a 28-day hormonal cycle, men run on a brisk 24-hour testosterone loop: peaking in the morning, dipping by night, and rebooting while they sleep. Yes, you too are governed by hormones. Congratulations, you have a cycle! Yet, testosterone (T) doesn’t just manage erections, but is rather a multitasker that regulates mood, energy, muscle mass, bone density, fat distribution, even the efficiency of your metabolism. So when levels dip, it’s not just a libido lull, but a flashing dashboard light.
As with most things, testosterone levels begin to decline gradually around the age of 30, dropping about 1% per year. But here’s the good news: sexual activity isn’t just the result of testosterone, but also the fuel that keeps the engine running. A 2007 study found that men who had sex more often also had higher testosterone, even after controlling for age and health. Another research paper showed that simply anticipating sexual activity drove small but measurable T spikes. And a 2024 study by Catena et al., which tracked saliva samples and courtship logs, found that daily testosterone fluctuations aligned more closely with the pursuit of desire such as flirting, initiating, and expressing interest, rather than with raw sexual desire itself. In other words, testosterone doesn’t just fuel lust — it responds to effort. Turns out, hormones like a bit of foreplay too.
And this is where things get interesting, because it challenges a century of oversimplified locker-room talk: “If I have low testosterone, my sex drive will be low, too.” The truth? It’s messier than that. Yes, testosterone influences desire, but desire also feeds back into testosterone. So it’s not a one-way street, but just another feedback loop. And if other systems in the body like blood vessels, nerves, or the metabolism are underperforming, boosting testosterone alone won’t bring out a standing ovation.
Epidemiological studies reinforce this complexity. Low T has been linked to higher rates of cardiovascular disease and all-cause mortality (Lincoff et al., 2023). But clinical trials of testosterone replacement therapy (TRT) are conflicted. It can help in some cases, but it’s not a pharmaceutical fairy godmother. If your vascular system is stiff, nerve pathways are damaged, or receptor sensitivity is down, flooding your system with testosterone may only yield marginal gains (Yang et al., 2023). However, for men with mild to moderate vascular health, TRT can actually help support overall vitality, boost energy, and rekindle some of that long-lost sexual appetite. But let’s be clear: testosterone is fuel, not a miracle mechanic. After all, your body is a classic car, not a Tesla. So please, for the love of science, read the dashboard lights before blaming the fuel.
Paging Dr. Morningwood
All this ultimately brings us back to Bryan Johnson and his now-infamous erection spreadsheet. Because even if you roll your eyes at the groin-strapped wearables, the science he’s tapping into is far from unhinged. Sleep erections aren’t just a quirky side effect of REM, but rather a real-time signal of vascular performance. And if that signal weakens, it’s not just your libido on the line. It might be your aorta.
A growing body of research links Nocturnal Penile Tumescence (NPT) to vascular health. Clinically, NPT helps distinguish the causes of erectile dysfunction and if it’s still working in your sleep, the hardware’s likely fine. But abnormal patterns like a shorter duration, weaker rigidity, fewer events often signal early vascular disease. Congruently, a 2019 meta-analysis found that poor NPT isn’t just a bedroom inconvenience; it’s often an early marker of endothelial dysfunction and atherosclerosis. Even in otherwise healthy men, weaker nocturnal erections have been tied to stiffer arteries and impaired vessel dilation which can be warning signs routine check-ups can miss.
Another study by Kamalov et al. found that men with shorter, weaker nocturnal erections were significantly more likely to have silent coronary artery disease, often before cholesterol or blood pressure raised any red flags. Fascinating, I know. And here’s the (scientific) climax: NPT is tightly tied to testosterone. When T levels drop, nocturnal erections often vanish with them.But the feedback loop works both ways, as regular REM sleep and consistent sexual activity help sustain testosterone production. So if your erections start to disappear in the night, it might be not just a red flag for your sex life, but perhaps the earliest memo your heart and hormones will ever send.
And now, class, stethoscopes down and hands where I can see them; we’re writing a test! Or are you already in deep sleep, fantasizing about the next anatomy lesson? Either way, I hope you’ve been paying attention and taken mental notes. Because whether it's your heart, your hormones, or your nighttime hard-ons, do remember: biology always comes with a pop quiz. And sometimes, the stiffest subjects are the ones that teach us the most.