AMA #7: Cold Exposure, Maximizing REM Sleep & My Next Scientific Studies

I also would caution that if you are getting into saunas that are too hot... I don't recommend doing that. In fact, I don't recommend doing deliberate cold exposure, exercise, or deliberate heat exposure if you're feeling really not well.

If you're doing that 1-10 minute deliberate cold exposure, and then you're getting warm afterwards and heading about your day, I can't see how the deliberate cold exposure itself would enhance your susceptibility to getting sick.

If you're feeling like you have to rest, you're tired, you're not feeling good because of a cold or because of a flu or because of a bacterial infection... then I would say stay out of deliberate cold exposure; don't use it.

Deliberate cold exposure or deliberate hyperventilation will increase those molecules, norepinephrine and epinephrine; and their increase is pro-immune. It can trigger the activation of immune cells and immune molecules that can make you more resistant to certain forms of infection.

Despite what you read about deliberate cold exposure or cyclic hyperventilation allowing for the deployment of immune molecules or increasing the number of immune cells that you're making, avoid anything that's stressful or challenging—whether or not it's a cold challenge, a heat challenge, or an exercise challenge—when you're feeling run down.

I am a big believer in using nasal breathing whenever you don't have to breathe through your mouth ... If you're doing zone 2 cardio, low-level cardio, or you're just walking along; it's very clear based on a growing amount of data that being a nasal breather is better than being a mouth breather.

I don't suggest anyone ever allow themselves to stay really cold after deliberate cold exposure for more than 10-15 minutes or maybe half an hour. Get bundled back up or put on clothes. If it's a nice hot sunny day, get out in the sun and warm up.

It's very clear that deliberate cold exposure can increase the release and the production of different immune molecules and immune cells.

Cold dry, air does seem to increase our susceptibility to viral and bacterial infections.