Well, realistically, as we grow older, with or without AIHA, the body deteriorates.
We should all know that.
But we CAN slow down the ravages of age significantly.
My cardiovascular exercise of choice is swimming.
I can see and feel a difference but a pool won’t always be available.
Just choose an exercise routine that fits the parameters of your abilities. That’s all.

Lower expectations. You will likely never function at your previous level activity.
Make choices. There are poor days, okay days and good days. Work with it.
Forgive yourself.

This all plays into the logic of understanding our own parameters of ability. My exercise of choice is swimming. There is minimal risk of injury.
But any exercise that raises the heart and respiration rate over a controlled period of time with work for a useful cardiovascular workout.
My alternate routines are power/fast walking and climbing stairs.

If for whatever reason, we stop our routine workout and then resume it sometime later, just beware! The body must readjust and we need to know at what rate. Resume the workout gradually.

Give yourself a break when it comes to your stamina - I use to be very hard on myself when my fatigue interfered with my job, daily household chores, and especially not being available for "supermom" duty - I continually pushed myself - and paid dearly for it - I now take things on a day to day basis - and accept what I'm ABLE to do 💜