Full Transcript: Deliberate Cold Exposure
Andrew Huberman's comprehensive 135-minute breakdown of cold exposure protocols. Click any timestamp to jump to that moment in the video.
Welcome to the Huberman Lab Podcast, where we discuss science and science based tools for everyday life. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today, we are going to discuss the use of deliberate cold exposure for health and performance.
Temperature is a powerful stimulus on our nervous system and indeed on every organ and system of our body and cold in particular can be leveraged to improve mental health, physical health, and performance.
I'd like to make a point now that I'm going to make several additional times during today's episode and that is that temperature is a very potent stimulus for the brain and body. That also means that it carries certain hazards if it's not done correctly.
Everyone shows up to the table with a different background of health status and there's simply no way that I can know what your health status is. So anytime you are going to take on a new protocol, you should absolutely consult a board certified physician before initiating that protocol.
I'd like to highlight a study that I find particularly interesting. The title of this study is brief aerobic exercise immediately enhances visual attentional control and perceptual speed. They had two groups. One group did 15 minutes of jogging at moderate intensity. The other group did 15 minutes of relaxation concentration that is somewhat akin to mindfulness meditation.
The major takeaways from this study are that the 15 minutes of jogging group experienced elevated levels of energy for some period of time after they ceased the exercise whereas the group that did mindfulness meditation actually reported feeling more calm and having less overall energy.
Before we talk about deliberate cold exposure and its many powerful applications, I'd like to highlight two core concepts. The first is understanding your baseline circadian rhythm in temperature. Your temperature minimum is approximately two hours before the time you wake up. Your temperature rises with waking and tends to continue to rise throughout the day.
Let's do what's called a Gedanken experiment. Let's say I send you out into the desert heat for a jog and it's very hot outside. Then I offer you a cold towel and ask where are you going to place it. Most of you would think that the best way to cool yourself off would be to drape that towel over your head, maybe your neck, over your torso.
Well, that's exactly the wrong approach if you want to cool off. Your body temperature would continue to increase even more than had you not placed that cold towel on your head or your torso. And here is why.
The surfaces that are best for cooling are what we call glabrous skin surfaces. The upper half of the face, the palms of your hands and the bottoms of your feet. These surfaces are unique in that just below them, the vasculature is different than elsewhere in the body. You have what are called arterio-venous anastomoses. These are portals of blood that go directly from arteries to veins and allow the body to dump heat more readily, more quickly.
When we talk about deliberate cold exposure, almost always that means getting uncomfortable. And one of the most common questions I get is how cold should it be? How cold should the water be? And I just will tell you now that how cold depends on your cold tolerance, your core metabolism, and a number of other features that there is simply no way I could know or have access to.
So I would like you to use this rule of thumb. The environment that you place yourself into should place your mind into a state of whoa, I would really like to get out of this environment, but I can stay in safely.
The second most common question I get about deliberate cold exposure is whether or not cold showers are as good, better or worse than cold water immersion up to the neck. I'm going to make all of that very simple for you by saying cold water immersion up to the neck with your feet and hands submerged also is going to be the most effective. Second best would be cold shower. Third best would be to go outside with a minimum amount of clothing.
What happens when we get into cold is that we experience an increase in norepinephrine, in noradrenaline release and in adrenaline release. Deliberate cold exposure is an opportunity to deliberately stress our body and yet, because it's deliberate and because we can take certain steps, we can learn to maintain mental clarity, we can learn to maintain calm while our body is in a state of stress.
And that's what we call resilience or grit or mental toughness — our ability to lean into challenge or to tolerate challenge while keeping our heads straight, so to speak.
I favor a protocol in which you build mental resilience and mental toughness through counting walls. What do I mean by walls? I mean the sensation of, no, I don't want to do this and the idea or the sensation in your brain and body that you actually want to leave that environment and go warm up.
If you are feeling very resistant to getting into the ice bath or cold shower and you manage to do that, that's going over what I would call one wall. Then for some period of time, you might actually feel comfortable in the ice bath. But inevitably, the next wall will arrive. And I would encourage you to pay attention to when that next wall arrives.
I think the 11 minute threshold, meaning 11 minutes total of deliberate cold exposure per week is a pretty good number to use if you need a number in order to keep you consistent. For some of you, getting into a cold shower for three minutes total for the whole week will represent a tremendous achievement. For others of you, three minutes is nothing.
I recommend that you get at least 11 minutes total per week, but at the point where 11 minutes total per week is very easy for you, then I would say either lower the temperature safely, extend the duration safely, or increase the frequency.
Deliberate cold exposure has a very powerful effect on the release of dopamine in our brain and body. And this is one of the main reasons why people continue to do deliberate cold exposure. Basically it makes us feel good and it continues to make us feel good even after we get out of the cold environment.
The subjects experienced a 250% increase in dopamine concentrations, which is still a very large increase in baseline levels of dopamine. And what was interesting is that those increases in dopamine persisted for a very long period of time afterwards, even out to two hours.
The group that was in 14 degrees Celsius, meaning 57. 2 degrees Fahrenheit, water for an hour experienced a 350% increase in metabolism. These are huge increases in metabolism. The plasma or serum levels of norepinephrine in the blood increased 530%.
These increases in norepinephrine are huge and long lasting and these increases in dopamine are very large and long lasting. And I do believe that these documented effects in humans explain much of the enhancement of attention and of feelings of wellbeing and mood that people typically experience after doing deliberate cold exposure.
Now I'd like to shift our attention to the effects of deliberate cold exposure on metabolism. What they did is they looked at deliberate cold exposure in this group of young men, and they used that 11 minute threshold per week. They divided that into two sessions although it probably is not important that it be two sessions, it could be three or even four sessions, as long as it reaches that 11 minute threshold.
What they discovered was that by going into these cold environments for 11 minutes total per week divided into two or four sessions, that these men experienced increases in so-called brown fat thermogenesis and increases in core body temperature that translate to increases in core body metabolism.
White fat doesn't burn many calories. It's basically a storage site. Beige fat and brown fat acts as sort of a furnace that can increase core body temperature. When norepinephrine released during cold exposure binds to receptors on white fat cells, it activates pathways that increase mitochondrial density. The cell becomes thermogenic. It starts burning calories to generate heat.
Having more beige fat and brown fat can increase your overall core metabolism, in other words, the number of calories that you burn per day, and therefore the number of calories that you need to either maintain or to lose weight.
If your main goal is hypertrophy and strength, it is probably best to avoid cold water immersion and ice bath immersion in the four hours immediately following that strength and or hypertrophy training. If you're really neurotic about this, then perhaps you'd want to move the cold water exposure to a different day entirely.
However, doing cold water immersion after a hard run, endurance training, or even sprint and interval training, there's no reason to think that cold water immersion or ice bath or cold shower would inhibit the progress that occurred during that training session.
Cold water immersion was an effective recovery tool after high intensity exercise. They observed positive outcomes for muscular power, muscular soreness — meaning reduced muscular soreness — increased muscular power, perceived recovery after 24 hours of exercise.
The basic takeaway was that cold water immersion performed after high intensity exercise was beneficial from a number of different standpoints and indicated that shorter duration cold exposure and lower temperatures can improve the efficacy of cold water exposure if used after high intensity exercise.
To wrap up, we covered a tremendous amount of material today about the use of deliberate cold exposure. We talked about how to leverage cold for sake of mental performance and building resilience. We talked about how to use cold for sake of elevating mood and focus through increases in dopamine and norepinephrine.
We talked about metabolism and the conversion of white fat to beige and brown fat and the 11 minute per week threshold. We talked about the use of deliberate cold exposure for recovery from exercise and when to avoid it if your main goal is hypertrophy and strength training.
The key is to approach this systematically, to understand the mechanisms, and to apply the protocols in ways that are safe and effective for your particular goals.
