Huberman LabAMA #7: Cold Exposure, Maximizing REM Sleep & My Next Scientific Studies
At a glance
WHAT IT’S REALLY ABOUT
Cold Exposure, Immunity, and Illness: Huberman’s Nuanced Science-Backed Guidelines
- Andrew Huberman uses this AMA to answer whether deliberate cold exposure can cause you to get sick, and whether you should use cold when you already have a cold or flu.
- He explains that short, controlled cold exposure itself is unlikely to cause infection, but cold, dry air and prolonged post-cold shivering in such environments can weaken mucosal defenses and increase susceptibility.
- Huberman reviews human studies showing that repeated cold exposure and hyperventilation-style breathing can modestly increase certain immune markers, but can also suppress aspects of the immune response and symptoms via elevated adrenaline and noradrenaline.
- He concludes with practical rules of thumb: use cold exposure only when you’re feeling well, avoid all stressful physiological challenges when truly sick, warm up promptly afterward, and favor nasal breathing to support respiratory defenses.
IDEAS WORTH REMEMBERING
5 ideasShort, controlled cold exposure is unlikely to directly cause colds if you rewarm promptly.
Huberman emphasizes that 1–10 minutes of deliberate cold exposure in clean water, followed by effective rewarming (clothing, sauna, hot shower, sun), is not in itself a direct cause of upper respiratory infections. The main infection risk is not the cold water but what happens afterward in cold, dry air if you stay cold and are mouth-breathing.
Cold, dry air can thin mucosal linings and increase infection susceptibility.
Laboratory studies manipulating humidity and temperature show that cold, dry environments reduce the robustness of mucus in the nose and throat, making it easier for viruses and bacteria to enter and establish infection. Mouth breathing in such conditions accelerates drying, so staying in cold, dry air while shivering after a plunge likely increases risk, even if the plunge itself does not.
Avoid stressful cold, heat, or exercise when you are truly sick.
If you have clear illness-related malaise (from a cold, flu, or bacterial infection), Huberman recommends avoiding deliberate cold exposure, strenuous exercise, and very hot, stressful sauna use. The priority should be rest, gentle movement if possible, and allowing your body’s “sickness circuits” to direct resources toward recovery rather than adaptations to stressors.
Repeated cold exposure can modestly boost immune markers, but effects are not huge.
In a study of people exposed to 14°C (57.2°F) water for 1 hour, three times per week over six weeks, researchers observed trends (not strong statistical significance) toward increased IL‑6 and various T and B lymphocyte populations. These suggest a mild pro-immune effect of repeated cold exposure, but it’s not yet clear how that translates into real-world resistance to specific infections.
Adrenaline and noradrenaline can both enhance and suppress immune responses depending on context.
Deliberate cold exposure and cyclic hyperventilation increase epinephrine and norepinephrine, which can acutely stimulate immune activity and cell deployment. However, chronically elevated catecholamines—especially later in the day and over many days—can impair immune function and reduce the body’s ability to fight infections. Dose, timing, and frequency matter.
WORDS WORTH SAVING
5 quotesIf you warm up after a relatively brief one to ten-minute deliberate cold exposure, I can't see how the deliberate cold exposure itself would enhance your susceptibility to getting sick.
— Andrew Huberman
Cold, dry air does seem to increase our susceptibility to viral and bacterial infections.
— Andrew Huberman
If you're sick, stay out of deliberate cold exposure.
— Andrew Huberman
Deliberate cold exposure and deliberate hyperventilation will increase norepinephrine and epinephrine, and their increase is pro-immune… However, if they are elevated chronically, that can cause reductions in the number and efficiency of immune cells.
— Andrew Huberman
One of the additional reasons [to nasal breathe] is a main site of entry for infections is through the mouth, so keep that mouth shut unless you need to talk.
— Andrew Huberman
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