Articles

Research-first writing on sauna, heat, fertility, and men's health. What the evidence actually says, claims examined.

Most Sperm Count Conversations Skip the Body Part That Absorbs Whatever You Put Next to It
A few years back, I fell into a research rabbit hole that started with a simple question: if sperm counts really have dropped by half since the 1970s, what are we all missing? I read the big meta-analyses, the phthalate studies, the microplastic panic pieces. But the thing that stopped me cold wasn’t a chemical. It was a dermatology paper from 1971. The kind of study that rarely gets mentioned in fertility talk because it lives in a completely different part of the library. And it flips the whole conversation... Read more...
When Freezing Sperm Is Actually Plan B
A lot of men treat sperm banking like a fireproof safe. The thinking goes: freeze a sample now, and you lock in a clean, young version of your fertility before anything goes sideways. Pay a few hundred bucks a year in storage fees and you're covered. It is a reassuring story. But it skips over the part nobody in the industry is eager to advertise-the decade that actually determines what goes into that sample in the first place.A frozen sperm sample is not a pristine backup from age 22. It... Read more...
Forget Heat Retention—Finnish Sauna Builders Cared About Something Else Entirely
Finnish men who sit in a sauna 4 to 7 times a week are 40% less likely to die from cardiovascular disease than men who go once a week. That statistic comes from the Kuopio Ischemic Heart Disease Study, a project that tracked over 2,300 middle-aged men for two decades. It’s not a fluke. The relationship was dose-dependent-more sessions meant better outcomes. The lesson from that data isn’t just “sauna is good.” It’s that frequency is the driver. The habit itself is the intervention.That changes everything about how you choose... Read more...
Your Sauna Bench Is Absorbing More Than Heat. Here's What the Research Says.
I went down a rabbit hole a few months ago. When I decided to put a sauna in my backyard, I figured the hard part would be choosing between a barrel and a cabin, or maybe figuring out the electrical load. The forums all circled the same things: cedar versus hemlock, 6kW versus 8kW, vapor barriers and drainage gravel. None of that turned out to be the thing that stuck with me.What stuck with me was something I stumbled across in old dermatology journals while trying to understand whether what... Read more...
Why Finnish Saunas Have Always Been Dark (and Why You Should Unscrew That Bulb Tonight)
A few winters ago I framed in a small sauna in the basement. Four by six feet, secondhand Harvia heater, and a single 100-watt bulb in a porcelain fixture overhead. The first few sessions felt like sitting inside a headache. The light was harsh, the heat felt aggressive, and I’d leave the sauna annoyed instead of grounded. One night I unscrewed the bulb in frustration and sat in the dark. The difference was immediate. The heat softened. My mind stopped spinning. I slept like a dead man that week.That accidental... Read more...
When the Heat Hits Your Body Differently: The Wood vs. Electric Sauna Divide the Research Never Tracked
Finnish men who sauna 4 to 7 times a week have a 40% lower risk of dying from cardiovascular disease compared to men who go once a week. That stat comes from a 20-year study of over 2,300 men in the Kuopio region, published in JAMA Internal Medicine, and it is the kind of finding that makes you stop and pay attention. The relationship was dose-dependent. More sessions, better outcomes. What that study, and nearly every major piece of sauna epidemiology since, does not record is the type of heater... Read more...
The Hour After Your Workout Matters More for Sperm Than the Workout Itself
Most guys who lift and think about fertility end up fixated on testosterone. More squats, more deadlifts, maybe a bigger spike. But after months of reading the actual exercise science and reproductive physiology, I kept coming back to something else. The 60 to 90 minutes after you leave the gym. That window-when you're hot, damp, and probably still wearing the same synthetic shorts-is where the real story plays out. Your training program probably isn't hurting your sperm. What you do after training might be.This isn't medical advice, and I'm not... Read more...
The Setup Is Shifting: Where Sauna and Cold Plunge Are Headed in the Next Decade
A friend sent me a video last week. A guy in a puffer jacket stands in snow up to his shins, pointing at a whiteboard covered in numbers. He explains the optimal ratio of time in his barrel sauna to time in his galvanized cold plunge. There are graphs. He refers to his setup as "the protocol station."Ten years ago, this combination existed in a handful of places. Finnish summer cottages. Russian bathhouses. Japanese onsen towns. High-end athletic training facilities. Now it shows up in suburban backyards, converted garages, and... Read more...
Prenatal Testing’s Blind Spot for Fathers With Infertility
The first genetics counseling session I ever observed went exactly like this: the counselor fired question after question at the woman. Family history. Carrier status. Age-related risks. The man sat off to the side, arms crossed, saying nothing. He was there to provide a sperm sample and moral support. When his side of the genetic story finally came up, it got maybe five minutes tacked onto the end, almost as an afterthought.That was over a decade ago. Walk into most prenatal testing conversations today and the script hasn’t changed. The... Read more...
The 4-7 Times a Week Sauna Rule? It Wasn't Written for Infrared.
You have probably heard the rule. Use the sauna four to seven times a week for the biggest health payoff. It shows up on fitness podcasts. Wellness blogs stamp it onto every top-ten list. I have even caught myself repeating it out loud before catching the assumption underneath.When I dug into where that number actually comes from, I found one landmark study. It was not about infrared sauna at all. The study followed middle-aged Finnish men using traditional saunas that ran at 80°C to 100°C, often with bursts of steam... Read more...