[p1mrx]

If you want to overclock a CPU, you need a decent power supply. If you want to overclock a brain, you need a decent heart and lungs. The point of cardio is to improve your body's power delivery, so it's one of the more accessible human upgrades.

For me, the biggest blocker was that I perceived sweating as a bad thing to avoid, until I realized that I could buy clothes to sweat in, and shower at arbitrary times, not just in the morning.