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

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

Huberman LabAug 7, 202531m

Andrew Huberman (host), Craig Heller (guest)

Physiological effects of cold exposure (showers, ice baths, local cooling)Heat as a primary limiter of muscular strength and enduranceGlabrous skin and specialized arterio-venous shunts (palms, soles, upper face)Differences between pre-cooling, per-cooling, and post-exercise coolingOptimal versus counterproductive cooling strategies during training and competitionPalmar cooling technology (Coolmitt) and performance case studiesSafety, hyperthermia, and signs of dangerous overheating

In this episode of Huberman Lab, featuring Andrew Huberman and Craig Heller, Essentials: Increase Strength & Endurance with Cooling Protocols | Dr. Craig Heller explores boost Strength and Endurance by Smart Cooling of Body’s Heat Portals Dr. Andrew Huberman and Stanford physiologist Dr. Craig Heller explain how targeted cooling of specific skin regions can markedly increase strength, endurance, and safety during exercise.

Boost Strength and Endurance by Smart Cooling of Body’s Heat Portals

Dr. Andrew Huberman and Stanford physiologist Dr. Craig Heller explain how targeted cooling of specific skin regions can markedly increase strength, endurance, and safety during exercise.

They distinguish between general cold exposure (showers, ice baths) and strategic cooling of “glabrous” skin—palms, soles, and upper face—where specialized blood vessels enable rapid heat exchange.

Local muscle overheating is presented as a primary, fast-acting limiter of performance, and properly cooling these portals between or during efforts can dramatically extend work volume and accelerate conditioning.

They also cover common but suboptimal cooling strategies (neck towels, ice packs on large muscles) and discuss a commercial implementation of the research (Coolmitt) plus simple DIY tests and protocols.

Key Takeaways

Local muscle overheating is a rapid, primary limiter of strength performance.

During anaerobic exercise, active muscles can increase metabolism—and thus heat production—by 50–60x, while blood flow to those muscles cannot increase nearly as much. ...

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Cooling your skin generally (neck, torso, big muscles) can feel good but may impair actual heat loss.

Cold towels or ice vests on the torso, neck, or head can trick the brain’s thermostat (in the preoptic anterior hypothalamus) into thinking the body is cooler than it is. ...

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The most powerful heat-loss portals are the palms, soles, and upper face (glabrous skin).

These areas are underlain by specialized arterio-venous shunts that let blood flow directly from arteries to veins, bypassing high-resistance capillaries. ...

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Ice-cold exposure on the portals is too cold and shuts the system down.

Plunging hands into ice water or gripping an ice-cold object causes reflex vasoconstriction in the glabrous vessels, closing the very shunts you want open for heat loss. ...

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Proper palmar cooling between sets can dramatically increase work volume and accelerate gains.

In controlled experiments, cooling the palms between sets (about three minutes per rest interval) allowed athletes to maintain performance and add sets rather than dropping off. ...

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Endurance in the heat can be roughly doubled by continuous portal cooling.

In a lab study at ~40°C ambient temperature with uphill treadmill walking, subjects using continuous cooling of palms/soles/face roughly doubled their endurance time compared to control trials without such cooling. ...

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Simple behavioral tweaks can improve real-world performance and safety, even without a device.

During activities like cycling or running, gripping handlebars or objects tightly can partially shut down heat loss from the palms; periodically relaxing the grip or briefly opening the hands improves cooling. ...

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Notable Quotes

You literally have the capacity to cook your muscles.

Dr. Craig Heller

One of the most immediate impairments of muscle activity, muscle fatigue, is the rise in temperature of the muscle.

Dr. Craig Heller

So from one day to two or three days later, with cooling, he doubled the total number of dips… and by the end of that month, he was doing 300 dips.

Dr. Craig Heller

You can feel great and have a dangerously hyperthermic temperature.

Dr. Craig Heller

You keep your gains. It's a true conditioning effect.

Dr. Craig Heller

Questions Answered in This Episode

For strength athletes, what specific temperature range and cooling durations on the palms have you found to be optimal for maximizing reps without triggering vasoconstriction?

Dr. ...

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In your treadmill studies at 40°C, how much did core temperature trajectories differ between subjects using standard field cooling (armpits/groin/neck) and those using palms/soles/face, and did any markers of cardiovascular strain differ?

They distinguish between general cold exposure (showers, ice baths) and strategic cooling of “glabrous” skin—palms, soles, and upper face—where specialized blood vessels enable rapid heat exchange.

Get the full analysis with uListen AI

Could chronic training with palmar cooling shift the temperature at which that key mitochondrial-fueling enzyme shuts down, effectively raising an athlete’s safe operating muscle temperature over time?

Local muscle overheating is presented as a primary, fast-acting limiter of performance, and properly cooling these portals between or during efforts can dramatically extend work volume and accelerate conditioning.

Get the full analysis with uListen AI

Given that facial and scalp cooling can help cool the brain, how would you design a protective protocol for combat sports that balances potential neuroprotection with the risk of masking dangerous systemic hyperthermia?

They also cover common but suboptimal cooling strategies (neck towels, ice packs on large muscles) and discuss a commercial implementation of the research (Coolmitt) plus simple DIY tests and protocols.

Get the full analysis with uListen AI

You mentioned that motivated athletes can push past warning signs into heatstroke; based on your data, what objective, field-usable metrics (e.g., heart rate drift patterns, grip temperature changes) could teams monitor in real time to prevent catastrophic overheating?

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Transcript Preview

Andrew Huberman

(peaceful music) Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science-based tools for mental health, physical health, and performance. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today, I have the pleasure of introducing Dr. Craig Heller as my guest on the Huberman Lab podcast. And now for my discussion with Dr. Craig Heller. Great to have you here.

Craig Heller

It's good to be here.

Andrew Huberman

Yeah. I know that I and many people have a lot of questions about the use of cold. So, one of the things that's happened in recent years is that, for many reasons, people have become interested in things like taking cold showers and taking ice baths for many different purposes.

Craig Heller

Mm-hmm.

Andrew Huberman

Could you just tell me a little bit about what happens when I get into a cold shower or an ice bath?

Craig Heller

Well, first of all, you get a tremendous shock, and what that's going to translate into is a bit of a shot of adrenaline. And I think this is really the, uh, so-called benefit, but it doesn't necessarily translate into any benefit in terms of your physiology, your performance, and so forth. Now, if you take a cold bath or a cold shower, uh, a couple of things are happening. One is you're going to stimulate vasoconstriction. 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. Uh, if you're in a true cold bath, the overall surface area of your body is so great that it doesn't matter if you vasoconstricted, you're still going to lose heat. Uh, the primary sites of heat loss, which we're going to get into, are the palms of your hands, the soles of your feet, and the upper part of your face. And the reason these are avenues for heat loss is they're underlain by special blood vessels, and these blood vessels are able to shunt the blood from the arteries, which are coming from the heart, directly to the veins, which are returning to the heart, and bypassing the capillaries, which are the nutritive vessels but high resistance. So you can tell when you shake someone's hand what his or her thermal status is. The hand's hot or it's cold.

Andrew Huberman

A couple of questions before we get into these specialized, um-

Craig Heller

Yeah.

Andrew Huberman

... uh, vascular sh- compartments on the soles, the palms, and, and the upper face. Is there anything that's, that's really important to understand about the difference in the physiological response evoked by th- by sh- cold shower versus immersion in cold?

Craig Heller

Uh, well, there are differences that are more physical than anything else. So if you are in a cold bath, and you're still, you develop a boundary layer. It's best to explain it in terms of a hot bath 'cause everybody's experienced that. You get into a hot bath and, "Oh my God, it's really hot, almost painful," and then you sit down, and eventually it doesn't feel so hot anymore-

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