Why does fighting drain so much stamina/energy.

Because it's a very stressful situation.

Anaerobic respiration (Boxing) vs Aerobic respiration (jogging). Boxing demands a high level of energy within short intervals. Your body will go through anaerobic respiration as a result; it will burn through energy faster to meet the demand. The reverse is true for endurance activities that require a steady and moderate amount of energy. If you were to sprint at your top speed for 100m, stop, and then do the same thing again until exhaustion, you'd find that the distance travelled would be less that the distance you could travel by simply jogging. Hence why interval training burns more fat and builds more stamina

Maybe because you are punching, and moving around. Also taking punches. Seriously though lol @ the question.

Yes a serious question, i mean even running on a treadmill requires less energy for me. But when i fight im fast as hell and punches are powerfull but i get tired quickly Compare running on a treadmill or jogging down the road to pushing a car down the road I guarantee the car will have you blowing like a banshee in no time and your legs will go to jelly , same with fighting it taxes all your system not just your aerobic conditioning , developing wind fitness is easy and relativity quick while muscle fitness takes time to build the core , fighting pushes everything emotional and physical .

Body shots also take a lot out of you, each one zaps your energy, knocks the wind out of you.

Anaerobic respiration (Boxing) vs Aerobic respiration (jogging). Boxing demands a high level of energy within short intervals. Your body will go through anaerobic respiration as a result; it will burn through energy faster to meet the demand. The reverse is true for endurance activities that require a steady and moderate amount of energy. If you were to sprint at your top speed for 100m, stop, and then do the same thing again until exhaustion, you'd find that the distance travelled would be less that the distance you could travel by simply jogging.

I have always wondered, is it because you're like using all your body power to transfer the energy into fast powerfull punches? Dehydration the body is weak without the proper fluids, your brain also needs to be rehydrated thats why Floyd wanted Canelo at 152, Canelo was dumb enough to fall for it so it's on him for having a dumb management team.

Yes a serious question, i mean even running on a treadmill requires less energy for me. But when i fight im fast as hell and punches are powerfull but i get tired quickly

Is this a serious question??

ok ok smart ass