It can. Many people use O2 to help push themselves to increase their stamina and endurance as well as strength. No one is suggesting that you push yourself beyond your abilities; I'm simply suggesting that you try to increase the time, distance or speed or intensity of your exercise very slowly. If you use a treadmill, for instance, see if you can't increase the speed by a tenth of a mile every two to three weeks or faster if that works for you. The more you slowly push yourself, the stronger you become. Besides increasing the intensity of your aerobic workout, you should also work out with weights, doing exercises that will help strengthen the upper, lower and core muscle groups. While you may still need O2, you may not need as much and you will be able to do the fun things a lot longer. Many of us who exercise daily do so because we can then do the fun things in life. It's well worth the effort.

Jenny, start very slowly, as slow as you can and see how long you can without stopping. Then do that again and again until you've done 30 minutes. Do the same thing for the next four or five days. Then add some time, a minute or 30 seconds to the time you walk before stopping. Keep doing that until you can walk 30 minutes without stopping. Then you can add time, distance or speed. That's how you build your endurance.

I agree that exercise is a good thing
I am not able to walk much due to my joints and severe arthritis. Is riding a station ary bike just as well?

Ok that's what my dr said. I'll try it.

I try but tire and get breathless so quickly. It's difficult. But I keep going.