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

Aug 7, 2025 36m 19s 16 insights
In this Huberman Lab Essentials episode, my guest is Dr. Craig Heller, PhD, a professor of biology at Stanford University and a world expert on the science of temperature regulation. We discuss how the body and brain regulate temperature in different conditions and why conventional cooling methods, such as placing ice packs on the neck, do not effectively reduce core body temperature. Dr. Heller explains why cooling glabrous skin areas—the palms, soles and upper face—efficiently releases body heat and can significantly enhance physical performance and endurance. We discuss how targeted palmar cooling improves both short-term performance and long-term training adaptation in aerobic and anaerobic exercise. Read the episode show notes at hubermanlab.com.
Actionable Insights

1. Leverage Glabrous Skin Cooling

Actively cool the palms of your hands, soles of your feet, and upper face during or between intense exercise to rapidly dissipate heat from the body’s core and muscles, thereby increasing work capacity and endurance. These areas contain specialized blood vessels that efficiently shunt blood for heat loss.

2. Avoid Ice-Cold Glabrous Cooling

Do not use ice-cold temperatures (e.g., ice water) directly on glabrous skin (palms, soles, face) for cooling. This causes reflex vasoconstriction, sealing off the heat loss portals and making cooling less effective.

3. Test Glabrous Cooling Efficacy

To ensure effective cooling of glabrous skin, check if the cooled area (e.g., palm) feels warm to the touch after cooling. If it feels cold, it indicates vasoconstriction, meaning the heat loss portals are shut down and the cooling is not optimal.

4. Prioritize Glabrous Areas for Cooling

When attempting to cool the body, focus on applying cooling to the palms of the hands, soles of the feet, and the upper face. These areas cool the body twice as fast as applying cold packs to the armpits, groin, or back of the neck.

5. Consistent Cooling Builds Gains

Engaging in consistent cooling protocols during workouts leads to true conditioning effects and lasting performance gains. The body adapts to the increased work volume, leading to benefits like increased muscle contractile elements and muscle size.

6. Use Coolmit Technology

Utilize the Coolmit device by placing your hand into it and holding onto the cooling surface for approximately 2-3 minutes between sets or during endurance activities. This effectively cools the body and enhances performance, with the biggest benefit occurring in the first few minutes.

7. Crude Glabrous Cooling Method

For a crude cooling method, use a package of frozen peas or blueberries and pass it back and forth between your hands. Ensure your hands do not become too cold to avoid vasoconstriction.

8. Pre-Cool Before Aerobic Activity

Take a cool bath or shower before engaging in long-duration aerobic activity, especially on warm days. This increases your body’s capacity to absorb excess heat, delays the onset of sweating, and can potentially improve speed or distance.

9. Loosen Grip During Exercise

When cycling or using similar exercise equipment, avoid gripping handlebars too tightly, especially in warm conditions. This can impede heat loss from the palms and limit performance; periodically loosen your grip or expose your hands.

10. Wear Thin Hand/Foot Coverings

To maximize heat loss from hands and feet during exercise, opt for the thinnest possible coverings (e.g., gloves, socks) or go without them if safe and practical. Thicker materials impede heat dissipation.

11. Maintain Loose Hands While Running

When running, keep your hands loose, as if holding crackers lightly, rather than gripping them tightly or holding a phone. This posture can be more beneficial for performance by allowing better heat dissipation from the palms.

12. Cool Brain by Pouring Water

Pouring water on the head and upper face can have a cooling effect on the brain. Cooled blood from these facial regions can reverse flow into the brain’s venous circulation, acting as a cooling source.

13. Beware Subjective Cooling vs. Core

Avoid cooling the torso, neck, or head with cold stimuli (e.g., ice vests, cold towels) when overheated. This can trick the brain’s thermostat into feeling cooler than you are, potentially causing vasoconstriction of heat loss portals and allowing core body temperature to continue rising dangerously.

14. Recognize Hyperthermia Symptoms

Be aware of symptoms of hyperthermia, which include feeling exhausted, miserable, and having a very high heart rate (cardiac drift). These indicate a dangerously high core body temperature.

15. Cold Showers/Ice Baths Caution

While cold showers or ice baths provide a ’tremendous shock’ and a ‘shot of adrenaline,’ they may not offer significant physiological benefits for performance or heat loss. They can even stimulate vasoconstriction, making it harder for the body to get rid of heat.

16. Cooling for Brain Injury

Cooling the brain, such as by applying cold to the neck or head, is theorized to help decrease swelling, inflammation, and blood flow after brain injury. However, this idea is considered controversial and requires further investigation.