Mackenzie, practicing his sermon.

The Inertia


Over the past few years, human performance pioneer Brian Mackenzie has revolutionized how endurance athletes train. In many circles, “more is more” thinking remains dominant, but with sky high injury rates for pros and weekend Joes alike and the bodies of high profile athletes like marathoner Ryan Hall quitting on them early, it’s becoming increasingly clear that Mackenzie’s emphasis on quality trumps the high mileage mindset.

Recently, Mackenzie teamed up with Laird Hamilton and Gabby Reece to launch a new fitness lifestyle system named XPT (Extreme Performance Training), which is anchored by three words: Breathe, Move, Recover. In addition to bringing bleeding-edge water and land-based training to the masses, XPT explores the profound impact of restorative breathing and thermic cycling practices. I caught up with Mackenzie to learn more about the potent combination of heat and ice:

When did you first start experimenting with hot and cold recovery methods?


Years ago, during my ultra-marathon days, I signed up to crew for a buddy who was doing the Badwater [aka “The World’s Toughest Footrace”]. To prepare for the extreme heat of Death Valley I got in the sauna every day for two weeks, while some of the ultra guys were doing things like sitting in their garage with a heater on. Once I’d acclimated, everything seemed physiologically easier, like I had more room to perform.

Laird got me into the ice. After we worked out he said, “Now we’re going to do heat and ice,” and I thought, “Huh?” Since we stopped icing injuries because it blunts recovery I’d stayed away from cold, but now he’s got this tub of ice sitting there. I only stayed in for about 15 seconds and it was a real eye opener. Eventually I worked up to doing three minutes and felt incredible afterwards.


Hamilton, remembering to breathe.

What are some of the main benefits of combining hot and cold?


Beyond helping you recover better from training, it hits a neurological reset button, similar to when you take a 15 minute, deep REM cycle nap. You also tap into the endocrine system and get your hormones moving. Plus, you touch cellular receptors for temperature regulation that we normally neglect, so you can better handle hot and cold environments. It also positively impacts sleep. When I do three or four ice and heat cycles in the late afternoon I’m starving afterwards because my mitochondria have been stimulated, and then I just want to lie down. You also rev up your metabolism.

If you’re combining heat and ice after working out, it’s best to wait at least an hour after going hard. Otherwise you’ll inhibit recovery. But if you’ve done a lower intensity session and don’t feel fried, then you can do it right away without interfering with adaptation.

Can newbies start by combining a hot bath and cold shower?

Absolutely. You should start with the cold shower – even if it’s just for 30 seconds or a minute – before getting in a hot bath. And then you always end on cold. You could also dip your hands in bowls of ice water. Once you’re used to this, try 30 seconds in an ice bath, and then get out and warm up, even if it’s just standing in the sunshine. Then get back into the cold water for another 30 seconds. With the sauna, most people can handle 10 minutes at 140 or 150 degrees, but everyone’s physiology is different. If you start to feel claustrophobic then get out. Just listen to your body and, again, finish the session with cold exposure.

I’ve seen guys take it way too far too soon – they’re still blue a couple of hours after being in a 40-something degree ice bath for 10 minutes. Don’t think of it as a competition, but instead let your comfort level and how you feel be the guide to what you can handle and how you’re adapting.

When you’re first exposed to cold you freak out and react to the shock with the fight-or-flight response.


How does breathing tie into the heat and ice approach?

It’s essential. When you’re first exposed to cold you freak out and react to the shock with the fight-or-flight response. Breathing from your diaphragm helps you calm down and focus on the moment. Wim Hof’s breathing method raises your alkalinity, which brings your pain receptors down. I’ve stopped using a timer in the ice bath, and instead take 30 to 40 slow, controlled breaths, one exhale breath retention, one inhale breath retention, and then get out. That takes me to about five minutes, which is just right. I’m a big believer in maximum effect with the minimum dose. A beginner could start with 15 slow breaths, which will help them improve their focus and have a better experience.


Only the best. We promise.


Join our community of contributors.