Not everyone has access to a traditional sauna or a sit-down infrared sauna. The convenient sauna blanket could be a good option for someone who wants the benefits of heat, but can’t get to a sauna. We tested the blanket to understand better if there is a positive effect from being inside a sauna blanket and how it may be different from a traditional sauna. Saying that a modality feels good/bad may be fine, but I like to have some sort of metric to see what is actually happening. For me, that was my morning check-in with my heart rate variability and resting heart rate. I have done this every morning for several months, so I have a good idea of my ranges. Wow did I get a shocker when I checked my data.
Being a devotee of the traditional sauna, with all its well-documented benefits, I was a bit skeptical of this new product. As Dr. Scott explained on the SuperAge podcast, infrared saunas are very different from traditional ones in terms of their effects on the body. The first is a hormetic stressor, essentially cardio training while not moving, whereas the infrared version will reduce stress, activating the parasympathetic nervous system which activates our resting and digesting. One upregulates, the other downregulates.
In my first test the sauna blanket was at a level 4 out of 9, for 30 minutes. Compared to a 190-degree traditional sauna, it did not feel at all hot. My heart rate went up modestly to around 68 from a resting rate of 50, as compared with the traditional hot box where my heart rate will be closer to 120. I took this as an indication that the new human hot pocket was not doing much. Following a cool shower, I went to bed, and checked my HRV in the morning. I use Heart Rate Variability to indicate how much stress I am under and how much physical stress I can handle in a day. For the first time in my life, my HRV was over 80. That was an attention grabber, but was it a fluke?
The next night I repeated the experiment, this time at level 7 for 35 minutes, which definitely had me hot and sweaty. My heart rate got to around 90 by the end of the session. Again, I took a cold shower, wiped out the inside of the blanket, and went to sleep. On awakening, my sleep efficiency, as measured on my WHOOP, was an excellent 94%, and once again my HRV was over 80. The previous day, I had a hard workout and would have expected my HRV to be in the high 60s. So this second day over 80 was a big deal.
I repeated this for 10 days, and there was a very clear trend of my average HRV up by 10, which is a notably unexpected increase. Since then, I have been using it pretty much every night. Why is this HRV number important? It is a good measure of how much residual stress your body is holding, and there is very good data on the relationship of HRV to mortality — higher HRV, less chance of dying. Although I can’t say for that using the sauna blanket will have you living longer, I can say that it reduced a key stress metric for me that is associated with morality.
This is just me. It may or may not do the same thing for others. The first time I got in the blanket it did seem a bit odd, which I quickly got over that.
Sauna blanket tips:
- Wear heavy socks or your feet will become impossibly uncomfortable.
- Wear clothes you are ok getting sweaty in because you could be drenched by the end of the session.
- Hydrate. I have about 8 oz of water with LMNT beforehand.
- The inside of the bag is easily wiped clean. No issues with hygiene that I have sensed.
- If you use it lying on a sofa watching TV, get a towel for your soon-to-be-sweaty head.
- Pre-heat the blanket for 10 minutes before you get in.
- If you are used to a traditional sauna, this is very different. It will not feel as hot, but it is working.
- If you get into the sauna blanket after a workout, it amplifies your body’s already heated state.
- I recommend using it before bed. The cooling of your body once you get out of the sauna blanket will be a powerful sleep signal.
- I live in a place with 7 months of winter. Will it take the chill off a late night walk? 100%.