In 2023, my husband had open heart surgery. When something like that happens to the person you share your life with, you start looking hard at everything that might tip the odds in your favor. Diet, obviously. Exercise, obviously. We were already very focused on both of those. But my investigation also sent me deep into the research on a habit I'd always filed under "maybe someday or when I have the money": sauna.

What I found surprised me enough that we invested in a Sunlighten sauna of our own. Here's the short version of what the research actually says.

The Finnish data is remarkable.

The most famous evidence comes from Finland, where sauna is practically a birthright and researchers have been tracking bathers for decades. A landmark study in JAMA Internal Medicine followed more than 2,300 middle-aged men for over 20 years. Men who used a sauna four to seven times per week had a 63 percent lower risk of sudden cardiac death compared to once-a-week users. Session length mattered too: more than 19 minutes was meaningfully better than under 11.

For years the obvious criticism was that the data only covered men. Then a follow-up study in BMC Medicine tracked nearly 1,700 men and women for 15 years and found the same pattern in both sexes: four to seven sessions per week was associated with a 77 percent lower risk of fatal cardiovascular events after adjusting for established risk factors, and the relationship was dose-dependent with no threshold. More was consistently better.

Why would sitting in a hot room do this? A comprehensive review in Mayo Clinic Proceedings lays out the mechanisms: improved endothelial function, reduced arterial stiffness, better blood pressure and favorable changes in the autonomic nervous system. Your heart rate climbs to levels comparable to moderate exercise. In a real sense, heat is a workout your cardiovascular system does while you sit still.

Now the caveat, because you know I always have one.

These studies were done with traditional Finnish saunas, which run hotter than the infrared sauna we own. Infrared has its own emerging evidence base. Japanese research on Waon therapy, a repeated far infrared heat treatment, found in the Journal of Cardiology that heart failure patients who received it had roughly half the rate of cardiac events over five years compared to standard care. But the big mortality studies above are traditional sauna specifically. I chose infrared anyway because the lower operatin

g temperature makes longer, more frequent sessions realistic for us and frequency is the variable the Finnish data says matters most. Observational data also can't fully rule out that healthier people simply sauna more, so keep that in mind too.

The infrared bonus: red light.

One thing I've come to appreciate about our setup is that many infrared saunas, including Sunlighten's, incorporate red and near-infrared light therapy alongside the heat. The evidence here is earlier-stage than the cardiovascular data, but red light has a significant research base. The mechanism was mapped out in a widely cited paper in IEEE Journal of Selected Topics in Quantum Electronics: the light is absorbed by cytochrome c oxidase in your mitochondria, which boosts cellular energy production. On the skin side, a 2025 review in the Journal of Cosmetic and Laser Therapy found red light improved skin texture and collagen remodeling. I think of it as a bonus layered on top of the heat session rather than the main event, but it's a nice two-for-one, and it's part of why I spend my recovery time in there after heavy training days.

No room or budget for a full sauna? You have options.

Sauna access has exploded in the last few years. Most big cities now have dedicated sauna studios and many gyms include infrared or traditional saunas with membership. If you want to test whether a regular sauna habit is something you'd actually keep before investing, a monthly studio membership is a low-commitment way to find out.

Or if you want your own but a full cabin isn't realistic, Sunlighten makes a single-person portable Solo System that folds up and stores in a closet. Same SoloCarbon infrared panels as the full-size cabins, a fraction of the footprint and price.

One timing note if you've been on the fence: Sunlighten's current sale ends Sunday July 12, and their saunas are HSA/FSA eligible through Truemed, which can save you up to 30 percent depending on your situation. We've had ours for over two years now and it's one of the few wellness investments I'd buy again without hesitation. If you want the full breakdown of our model, how we use it and what I'd tell anyone shopping, I put it all in my complete Sunlighten sauna review. If you decide to call them with questions directly instead of going through the website, be sure to mention Heal Noursih Grow to get their best partner pricing.

As always, hit reply if you have questions about how we use ours. I read everything and I always write back.

Have a great weekend,
Cheryl

P.S. If a sauna isn't in the cards right now, the research consistently shows the biggest cardiovascular lever you control is still consistent movement and strength training. The 30 Day Healthy Habits Challenge is a great free place to start.