The AC in my house broke this week.
It’s July in Atlanta, and the temperature hit 100 degrees. While waiting for the repair, I thought back to one of the first classes I took as a chemical engineer: thermodynamics. That’s where you learn the basics — how energy moves and how systems work.
Take an air conditioner. It runs on the refrigeration cycle — four steps in a loop:
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Compression – refrigerant gas gets squeezed, raising pressure and temperature.
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Condensation – the hot gas flows through outdoor coils and gives off heat. It turns into a high-pressure liquid.
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Expansion – the liquid passes through a valve, the pressure drops, and it gets cold.
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Evaporation – the cold refrigerant flows through indoor coils, pulling heat out of the air. It turns back into a gas.
That’s how your house stays cool — as long as every part is working. In my case, a fan stopped. The technician suggested I replace the whole unit. I didn’t say much, but I knew better. The refrigerant cycle was fine. The fan mattered, but it wasn’t a system failure. We replaced the fan, and everything worked again.
It helps to understand how the system works. You don’t have to be an engineer. But if you know the basics, you can fix the part that’s broken — not the whole thing.
Same goes for running.
Training is a system — stress, rest, recovery, nutrition. When something’s off, it doesn’t mean you need to scrap everything. You just figure out what needs attention, fix it, and keep going. That kind of understanding helps you stay steady. It keeps you moving forward.