Heat therapy & holiday wellness

Saunas are all the rage right now (and I DO love mine), but there is some new research available that shows a hot bath can be just as effective on some health markers.

Today I will share the links to the new research, a video with you where I break down the pros and cons of my sauna, and share my favorite magnesium bath protocol.

A couple quick things:

Black Friday Sale on Courses is here! Click here to get my lowest prices of the year - ending soon!

​Holiday Gift Guide (fully updated with new goodies as of today!)

MyCircadianApp - 50% off Lifetime Access this week only! click here (go to stories & select "Black Friday")

Let’s talk about something that’s probably in your feed right now: “You have to buy a sauna if you care about longevity.”

But here’s what the newer research is saying:

We now have data showing that passive heat therapy -things like hot baths, hot tubs, and saunas - share a lot of the same benefits for your cardiovascular system and metabolism.

Some key findings from recent papers on passive heat therapy and hot water immersion:

A brand-new study from the University of Oregon (published in American Journal of Physiology, June 2025) compared three forms of passive heat therapy:

• Traditional dry sauna

• Far-infrared sauna

• Hot-water immersion (hot tub)

Population:

20 healthy adults (men + women), ages 20-28, active/exercising regularly.

The researchers measured core temperature, blood pressure, heart rate, cardiac output, immune markers, and inflammatory cytokines before, during, and after each heat modality.

THE FINDINGS:

1. Hot-water immersion raised core body temperature the most.

   This is important because core temp rise is the primary trigger behind the downstream benefits of heat therapy (vascular shear stress, nitric oxide, insulin sensitivity, blood pressure improvements).

2. Hot-water immersion created the strongest cardiovascular response.

   Higher increases in:

   • cardiac output

   • heart rate

   • blood flow

   • vessel shear stress

   All of these are tied to better vascular health.

3. Only hot-water immersion produced a measurable immune response.

   They saw:

   • increased inflammatory cytokines (a normal, adaptive acute response)

   • shifts in immune cell populations

   Saunas did not produce this response in this study.

4. Why?

   Because in water, your body cannot cool itself by sweating - so the heat load is stronger and more sustained.

5. Bottom line from the researchers:

   Consistent heat therapy - sauna or hot water - improves vascular health, blood pressure, metabolic markers, and heat tolerance over time.

   But hot-water immersion delivered the strongest immediate physiological response in this study.

6. This does NOT mean saunas are useless.

   It means:

   • A hot bath or hot tub is not “lesser.”

   • You don’t have to drop several thousand dollars to get clinically meaningful heat benefits.

   • Consistency > equipment.

So no - you don’t automatically need a multi-thousand-dollar sauna to get great benefits from heat.

Is a good sauna amazing? Yes! 

Do you have to break the bank to care for your mitochondria? Not necessarily....

How I use heat therapy:

Here’s my setup and how I think about it:

1. My magnesium soak “sauna alternative”

If I don’t want to get in the sauna -or I’m traveling - I’ll do:

• A hot bath (comfortably hot, not scalding) for about 20 minutes in the evening
• This gives you: circulation, relaxation, nervous system down-shift, and a mineral top-off all at once.

2. My sauna and why I still love it

When I do use a sauna, here’s why I like it:

• It’s structured: I’m more likely to actually sit and sweat for a full session
• It stacks well with other tools like cold therapy
• I feel the difference in my sleep and recovery

If you’re curious about the exact sauna I use and the pros and cons, I did a full breakdown here:

👉Watch my breakdown of sauna's here 

And - my sauna is currently to $2,200 off + FREE shipping + FREE gift with purchase for Black Friday.

I also have many many clients who love the Bon Charge Sauna Blanket (it's 25% off right now) or the more portable - Sauna Space Sauna (it's 25% off right now also with code SARAHK)​

Bottom line: use what you have. A good hot bath done consistently beats an expensive sauna you never use!

Holiday wellness, without blowing your budget:

Since we’re talking about not over-spending on wellness toys… here’s how I’d prioritize if you’re trying to improve metabolic health, hormones, and circadian rhythm this winter:

1. My courses are at the lowest prices of the entire year right now for Black Friday.
   • If you need a full metabolic reset from a circadian + leptin lens → Leptin Reset ​
   • If you want to understand how to actually eat for your light environment and season - with food lists, recipes & protocols → Quantum Nutrition​
   • Or save big when you bundle them - Or even bigger with the big discount on Bundle of All Courses ​
2. MyCircadianApp, is also 50% off lifetime access right now.It helps you:
   • Track sunrise/sunset and UV (including vitamin D)
   • Keep your evening lux low (and morning lux high!)
   • ​Click here to grab the 50% off discount​
3. This is where things like magnesium soaks, saunas, red-light panels, vibration plates, etc. come in.

If you want ideas for this tier, I put everything I actually use into a Holiday Gift Guide for you:

​Click here to download my most updated gift guide​

How to use this info this week

• Don’t stress if you don’t own a sauna. Run a hot bath, add magnesium, and let your body heat up and cool down naturally afterward.
• If you do have a sauna, fantastic - use it like a structured training session for your blood vessels and mitochondria.
• And if you want to understand how all of this plugs into leptin, metabolism, circadian biology, and actual long-term fat loss… this is the week to grab the courses and the app while they’re at their lowest prices. (Click here for best deals of the year!)

Reply to this message if you have a question about which course makes sense for you!

Warm (literally),

Sarah