DAYP 13: Cool Yourself Properly for 3x the Gains

Using ice packs incorrectly may be detrimental to your performance. This week’s content looks at how to properly cool yourself down. Read on to find out how to gain a performance edge by cooling down properly.

By the end of that month he was doing 300 dips. Here is a professional athlete at peak physical condition and he triples the amount of work he can do.

– Dr. Craig Heller on a study where they cooled the palms of an NFL player’s hands to see what kind of performance improvement could be gained.

When it comes to exercise performance it’s often thought the reason we can’t go as long or do as many reps is because our muscles fatigue and we have to stop to rest. However, research by Dr. Craig Heller, Professor of Biology at Stanford, shows overheating is what limits our performance. Dr. Heller spoke with the Huberman Lab Podcast about where cooling happens on the human body and the performance benefits of properly cooling. His research led to the development of the Cool Mitt, a cooling glove which has tripled anaerobic performance (lift more reps) for professional athletes.

Misconceptions About Cooling Down

People think most heat is transferred through the entire surface area of our skin, but this is not the case.

The best locations or “portals” for cooling down or heating up are: 

  • Palms of our hands
  • Soles of our feet
  • Upper part of the face (above the beard line)

These above areas contain special blood vessels that can shunt blood from the arteries (which carry blood away from your heart) to the veins (which return blood to the heart). This bypasses the capillaries which have higher resistance which speeds up heating or cooling.

Cooling techniques people think work, but aren’t effective:

  • Ice pack to back of neck
  • Cold sponge over the head
  • Wearing an ice vest

Humans, like your house, have a thermostat which is located in the brain. This thermostat takes in temperature data from the overall body surface. Putting something cold on areas other than the portal areas is like trying to cool your house by sticking an ice pack on your thermostat. You end up tricking the sensor rather than cooling the body. While you might feel better with the cold towel, in reality your core temperature can continue to rise.

How to Properly Cool Down

  • Apply cold to the right locations. Heat transfer is best when done at the palms of our hands, soles of our feet, and the upper part of the face.
  • Cool, but not too cold. If you apply cold to the areas it should feel cool, but not ice cold. If you go too cold you cause your blood vessels to constrict which will seal in heat rather than lose heat.
  • Go without gloves. As the palms are a key area for cooling it’s best to avoid wearing gloves when working out.
  • Go barefoot. This is more challenging depending on the activities you do, but is another area where you can cool down.
  • Loosen your grip or let go. If you are doing exercise that involves gripping onto something (like cycling or rowing) loosen your grip or even better take one hand off to let it cool down.
  • Take a cold shower before aerobic activity. By cooling your whole body down before aerobic activity you allow your body to handle more heat which can lead to better performance.

Studies done by Dr. Heller and the results when properly cooling:

  • Tripled the number of dips. An NFL player doubled the number of dips he could do in a week by increasing the number of reps per set and increasing the number of sets. After four weeks of continuous training using this cooling tech, he was doing 300 dips. This is three times the amount he did when he first started.
  • No more sore muscles. They took untrained students and had half of the group use the cooling technology and the other half didn’t use it. The half that used the cooling tech did not have much if any soreness versus the control group.
  • Double the endurance. With a group of people walking on an incline treadmill they were able to double the length of time they could walk using cooling.

Additional Notes from the Interview:

  • Heat is the dominant mechanism that prevents more work from being done.
  • The primary locations / portals where we transfer heat are the places we don’t have hair
  • Interestingly all mammals have these portals
  • Called “glabrous skin” (no hair skin)… mammals have fur, but we have hair follicles. 
  • Boundary layers. It’s a layer where if you stay still for example in a cold bath the water right above your skin will heat up and stay relatively constant. Versus if you take a cold shower there is no time for a boundary layer to develop. The still water next to your skin comes to equilibrium temperature.
  • Most of the heat generated comes from food. We are 20% efficient at extracting energy from food. The rest is lost as heat.
  • A few degrees above normal human body temperature is hyperthermia. Individual muscles can experience hyperthermia before the rest of the body. The muscles have a fail safe where if temperature rises too high you won’t be able to do another rep. This is to protect you from cooking your muscles. This is muscle failure.
  • You may think oh i’ll just throw on a cool towel over my legs so I can squat more. The problem is your body surface is a good insulator and not a good heat transfer source so that cool towel won’t be able to cool your muscles down that well.
  • You could drink cold water, but you would need to drink a lot of water which could cause unwanted issues (dilution of blood).
  • Think of the brain as your thermostat and the body portals as the air conditioner. The temperature information from your overall body surface is sent to the thermostat.
  • Doing a cold towel around your neck will feel good as it will help cool down the brain, but this can be counterproductive as you might think you are ready to exercise again since your brain thermostat is getting the cold signal when the rest of your body still hasn’t cooled down yet.
  • Holding a bag of frozen peas or an ice bottle and periodically switching hands could work. A good way to test if this is working well is to touch the palm of your hand and see if it feels warm or cold. If it’s cold you’ve held on for too long and caused vasoconstriction. If it’s still warm you are probably ok.
  • For strength workouts you can’t use this protocol as the heat increase is localized to the muscle being used rather than raising overall core temperature. The only way heat gets out of the muscle is through the blood
  • You can cool the brain by pouring cold water on your head, but this doesn’t cool the entire body. It’s a localized effect.
  • Amazing effects when cooling is done properly. Gains are long lasting as you did the work.
  • They took female students and tested them on pushups with and without cooling. Those with cooling were able to do 800 push ups in about 45 minutes
  • They compared standard medical procedure for dealing with hyperthermia where they put cool packs in your armpits and groin area to cooling in the body’s natural heat portals (face, palms, soles of feet) and found cool down rate was doubled when using those heat portals

References, sources and more:

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