What causes you to get out of breath when you exercise?

When you are out of shape and exercise, what causes you to get out o breath and your lungs to burn, and what is the best way to increase your tolerance so your lungs are not burning?

  1. Hypoxia

  2. Exercise/Weight loss

Exercising uses muscles.
Muscles use oxygen.
Strained, underused, small muscles need more oxygen.

Tolerance (endurance) is built through repetition on a regular basis.

so how come you get out of breath when performing anaerobic exercise, if it is used without oxygen?

I guess “anaerobic” exercise is a bit misleading. It just means that the muscles are running anaerobically, not that the execrise doesn’t ultimately rrequire oxygen.

In simplified terms what happens is that the muscles run without oxygen, but they produce partially ‘burned’ waste products, mostly lactic acid. The longer the muscles run anaerobically the more of these partly burned waste products they produce. The products themselves are mildly poisonous and can only be detoxified by exposing them to oxygen.

That buildup of partly burned wastes causes what is referred to as an oxygen debt. And it’s a real debt in the sense that it has to be paid back eventually. Although the muscles might be able to run temporarily without oxygen they will need that oxygen eventually to get rid of those wastes. And eventually the waste builds up to such a level that the muscles simply can’t operate any more.

So you get out breath with anaerobic exercise because the body has to get enough oxygen to pay back that oxygen debt and get rid of the lactic acid that has built up. You may not be out of breath while doing aerobic exercise but you will be for quite a while after it finishes as your body struggles to pay back the debt.

Does changing how you breathe (say, taking larger breaths or simply breathing faster) help with this? Or do the muscles’ needs simply outweigh whatever incremental benefit deeper/faster breathing brings?

Breathing technique can certainly help supply the body with more oxygen during exercise. That doens’t mean the muscles won’t still be running anaerobically and incurring an oxygen debt. What it does mean is that the parts of the body that can be running aerobically such as the internal organs, those mnsucles that are being used for posture and so forth will be running strictly aerobically. That has all sorts of benefits. It means the oxygen debt will be mainly limited to the working muscles os you can recover faster. It also controls unnecessary acid buildup in the bloodstream fromthose other sources. And of course by providing the active muscles with as much oxygen as possible you can often limit the oxygen debt allowing you to keep going for longer.

Exsctly how you should be breathing dependd on what you are doing of course.