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TODAY'S BRIEF:

Last week, one of you hit reply and told me about his experience with severe sleep apnea — and how treating it completely changed his erectile dysfunction. He asked why nobody ever talks about the connection.

So I went down the rabbit hole. And honestly? This might be the most underrated cause of ED that nobody is screening for.

Here's the short version: if you have erectile dysfunction, there's a very high chance you also have sleep apnea. And if you have sleep apnea, it's probably making your ED worse — or straight up causing it.

Let's break it down.

Sleep apnea is a condition where your airway collapses or gets blocked while you sleep. You literally stop breathing — sometimes for 10 seconds or more — and it can happen dozens of times per hour without you knowing.

About 1 in 3 men between 30 and 70 have it. That's roughly 22 million Americans and a billion people worldwide.

Here's how it gets classified: if you stop breathing more than 15 times per hour, that's moderate. More than 30 times? Severe. And severe sleep apnea has an 80% correlation with erectile dysfunction.

Some studies put the overlap even higher. One found that 92% of men with sleep apnea also had ED. That's not a coincidence — it's a direct biological connection.

And it goes both ways. If you have ED, your likelihood of having undiagnosed sleep apnea is extremely high.

Sleep apnea doesn't just make you tired. It attacks your sexual function on four fronts simultaneously:

1. It Tanks Your Testosterone

Every time your breathing stops, your blood oxygen drops. This disrupts the hormonal processes that happen during deep sleep — including testosterone production. Sleep apnea actively suppresses testosterone secretion. Lower testosterone = weaker erections, lower libido, less muscle, more fat. It's a cascade.

2. It Damages Your Blood Vessels

When you repeatedly stop breathing, your body goes into stress mode. Cortisol spikes. Inflammation rises. The endothelial lining of your blood vessels — the inner wall that controls blood flow — gets damaged over time.

Here's the key: erections are a blood flow event. Your penis requires healthy blood vessels that can dilate and fill with blood. Sleep apnea also decreases nitric oxide — the molecule that relaxes and opens blood vessels. Less nitric oxide = less blood flow = weaker erections.

It's almost a triple hit: inflamed vessels, constricted vessels, and less nitric oxide to open them.

3. It Kills Your Nightly "Systems Check"

This is the part most guys don't know about. Every night during REM sleep, your body runs a systems check on your erection. It's called nocturnal penile tumescence — basically, your brain pumps blood to your penis to make sure everything still works. It happens multiple times per night during healthy sleep.

When sleep apnea fragments your REM sleep — waking you up every few minutes with breathing interruptions — that systems check never completes. Over time, your body loses the ability to perform this function reliably. The hardware stops getting tested, and eventually it stops working during the day too.

4. It Wrecks Your Mental State

Sleep apnea causes chronic fatigue, depression, anxiety, brain fog, and irritability. All of these independently contribute to ED. When your brain is running on fumes, arousal and performance take a back seat.

It's not a willpower problem. It's not aging. It's your body being suffocated every single night.

Most men with sleep apnea don't know they have it. Here's what to watch for:

You might have sleep apnea if:

And the big one: if you have ED and can't figure out why, get a sleep test. Period.

Quick sidebar because this catches a lot of guys off guard. If you're waking up 2-3 times a night to pee, you probably assumed it was a prostate thing.

It might be sleep apnea.

When your airway collapses, it creates negative pressure in your chest. Your body misreads this as fluid overload and releases hormones that ramp up urine production. It also blocks antidiuretic hormone — the thing that's supposed to concentrate your urine at night so you don't have to get up.

Result: you're making way more urine than you should be, and you're waking up to empty your bladder multiple times. Treating sleep apnea with CPAP has been shown to significantly reduce nighttime urination by reversing these hormonal changes.

Step 1: Get Screened

You don't need to go to a sleep lab anymore. Home sleep tests are now accurate and easy — you wear a ring or wrist device, sleep in your own bed, and a specialist reads the results. Any physician can prescribe it. Tell your doctor: "I'd like a home sleep study to screen for obstructive sleep apnea."

If you already use a smartwatch that tracks sleep, that's a decent screening tool — but it's not diagnostic. If it flags anything, follow up with a real test.

Step 2: If You Already Use CPAP — Check Your Settings

If you're on CPAP and still have ED, your REM sleep might still be fragmented. This can happen from mask leaks or incorrect pressure settings. Use a free tool called OSCAR (sleepfiles.com/oscar) to review your data, or ask your sleep specialist to check for REM-specific events.

Step 3: Fix the Lifestyle Factors That Make Both Worse

The same habits that improve sleep apnea also improve ED:

Step 4: Talk To Your Doctor About Both

If you're being treated for ED but nobody has mentioned sleep apnea — bring it up. And if you're being treated for sleep apnea but nobody has asked about ED — bring that up too. These conditions are bidirectional. Treating one often improves the other.

Ask yourself three questions tonight:

If you answered yes to two or more — schedule a home sleep test this week. It could be the single most impactful health decision you make this year.

Your erection is a barometer for your overall health. And your sleep might be the thing that's silently breaking it.

That's your brief. Fix your sleep. Fix your sex life. It might be that simple.

— The Male Brief

P.S. Have you ever been diagnosed with sleep apnea? Did treating it change anything for you — energy, erections, weight? Hit reply — I read every response. Your stories shape future newsletters (like this one).

P.P.S. — The Sleep Apnea & ED Screening Checklist I mentioned is free. Printable, warning signs, risk factors, and exactly what to tell your doctor. → nunajohnson.com

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Created by Nuna Johnson