Essentials: Increase Strength & Endurance with Cooling Protocols | Dr. Craig Heller

This Huberman Lab Essentials episode opens with host Andrew Huberman introducing Stanford biologist Dr. Craig Heller. The transcript's speaker labels appear to be reversed: the person labeled "Dr. Craig Heller" introduces himself as Andrew Huberman and asks the questions, while the person labeled "Andrew Huberman" describes the cooling research and devices built by "our" group. This article follows the content, treating Huberman as the interviewer and Heller as the scientist explaining the physiology.

Huberman starts with the popular habit of cold showers and ice baths. Heller's first answer is skeptical. The immediate effect is "a tremendous shock" and "a bit of a shot of adrenaline," which he suggests is "really the so-called benefit." He says it "doesn't necessarily translate into any benefit in terms of your physiology or performance." Cold also triggers vasoconstriction, which shuts down the body's routes for losing heat. In a true cold bath, though, the body's total surface area is large enough that you lose heat anyway.

So if anything, it's going to make it a little bit more difficult for your body to get rid of heat because you're shutting off your avenues of heat loss.

Heller then introduces the idea the rest of the conversation builds on. The main sites of heat loss are the palms, the soles of the feet, and the upper face. These areas sit over special blood vessels that send blood straight from arteries to veins, bypassing the high-resistance capillaries. He notes you can feel someone's thermal state in a handshake: "The hand's hot or it's cold."

On showers versus immersion, Heller says the differences are "more physical than anything else." If you sit still in water, a boundary layer forms. He uses a hot bath to explain it: the water touching your skin comes into equilibrium with your skin and acts "like having a blanket on you or an insulator on you," until moving around disturbs it and you feel the full temperature again.

Heller says the question of benefit depends on whether the activity is aerobic or anaerobic. In sustained aerobic work, heat production rises gradually and spreads through the body until core temperature reaches a level that impairs performance. He says a cold bath or shower beforehand helps because it increases "the capacity of your body mass to absorb that excess heat." When Huberman asks about a cool shower before a long run on a warm or hot day, Heller agrees: "It'll take them longer to get to the sweat point and to heat up."