Eli5: Why do you get out of breath and your lungs burn after hill sprints?


I was running some hill sprints yesterday I’m the 20-30s duration yesterday, allowing myself a couple minutes in between rounds. A few sprints in, I notice my lungs just feeling on fire. I would have imagined that duration would make it anaerobic exercise, so then why would my lungs be burning and I’d be struggling to catch my breath if no oxygen is needed?

In: Biology

Anaerobic exercise makes a byproduct called lactic acid. This is what makes your lungs, and other muscles, burn.

Your body really, really, really prefers aerobic exercise. It can’t do anaerobic exercise forever, and too much lactic acid can hurt you.

If you are not used to exercise your lungs may not fully expand in your daily routine, leaving it kinda shrugged. This may lead to it becoming “glued” to itself in some areas, and when you start heavy breathing due to exercise you micro tear them, leaving a burning sensation.

And when you sprint, you don’t stop the aerobic side of your exercise from happening, it’s just that you add anaerobic metabolism on top of it for the extra energy. Your body doesn’t “switch gears”, it just push the nitro button.