Andrew Huberman· PhD
If you ever have gotten into a sauna that was very, very hot, maybe 210 degrees Fahrenheit, you sit there for a minute. You'll notice that your heart rate increases, and there are reasons for that, and we'll talk about some of the health benefits of that in a few minutes, but it's pretty uncomfortable. You may not feel like your skin is going to burn up, but you often will feel the impulse to get out, especially if you stay in there for a little while. That impulse is the consequence of this preoptic area communicating with your amygdala saying, "Hey, this environment is really hot, and I'm tryin' to cool down, and it's not really working. I'm dumping heat, but I'm not able to adjust the core of my body temperature in ways that are going to protect my neurons. And so it's a signal that you probably shouldn't stay in that environment too long. Now later we'll talk about the advantage of pushing yourself a little bit through some of these very hot environments, provided you can do it safely, but the impulse to get yourself out of a very hot environment is the consequence of the POA communicating with your amygdala, and the amygdala then, in turn, activating your adrenal glands, which sit right above your kidneys, the release of adrenaline, and this feeling of agitation like you want to move. Usually you want to move out of whatever hot environment you happen to be in.