A few years ago, I signed up for the Black Canyon 100K. It’s a tough race in Arizona, known to be warm for runners emerging from winter snows. Shortly after, I got tasked with a deployment. Not ideal timing, but not a dealbreaker either. I figured I’d train overseas, stay consistent, and hopefully be home in time to toe the line.
When I stepped off the plane, it felt like I had fallen into a hot tub. The air was thick and sticky, near 100% humidity, and the sun didn’t play around. Welcome to summer.
I got situated, got to work, and locked into a rhythm. My world shrank to two things: work and running. That was it. The base had a loop, just over two miles of dirt and roads, with a water spigot nearby where I could refill my bottle. Because of my shift, I usually ran when it was black flag conditions. In other words, too hot to train by military guidelines. Perfect.
The first few weeks were brutal. I’d finish a run and just sit there, drenched, chugging all the water I could get. I’d wring my clothes out like a soaked towel. During the run, the heat was my adversary. It tested me every mile, daring me to quit. It wasn’t just a workout; it was a battle of wills.
I started around 30 miles a week and I was lucky to go under 10 minute mile pace. Every two weeks, I added another 10. I hit a wall around 70 mpw, hovered there for a month, then broke through. By the time I left country, I had logged my first 100-mile week with 13 hours of running. Every step had been on that same dusty loop. Over and over. Same turns. Same sun. Same burning air.
Along the way, I ran with foxes, sidestepped snakes, and passed the Army out rucking. The loop was monotonous, but the fitness was real. I wasn’t just getting used to the heat; I was being changed by it.
By the end, I was annealed. Forged. Hardened by fire. The fittest I had ever been. I took a PT test a few weeks after I got home and clocked an 8:15 1.5 mile, which was my best by far.
Looking back, I know the heat drove real physiological adaptations: increased plasma volume, improved cardiovascular efficiency, and better sweat response. I could run harder, longer, and recover faster. The catch? Those adaptations don’t last. A few weeks out of the heat and they start to fade. But the memory, the mental armor I built, stayed with me. That’s the real gift of heat training. It doesn’t just change your fitness. It changes your relationship with suffering.
Those months taught me that the heat isn’t just something to endure. It’s something to embrace. There’s strength in the suffering. And fitness, real, deep, hard-earned fitness, can be found in the furnace.
This kicks off our Class 5 Heat Series. Next up: why heat training works, what it does to your body, and how it can unlock gains you didn’t know were possible.
If you're training through heat this summer, make sure your gear can handle it. Class 5 shirts are built to breathe, to dry fast, and to keep you moving forward when the temperature says stop.
