I just did my first STAND-UP workout. I was amazed at how weak my balance is during this particular workout. I quiver and I shake and I fall and I can't reach the end point of the poses. Oh well, better roll my sleeves up and practice, practice, practice until my muscles (and brain) gain enough confidence and strength to get the job done! LOL
Aging, infections (especially ear infections), head injury and many medicines may also result in a balance problem, but I have done of these situations going on, other than aging at 68-1/2 years young. I read where eating low-salt (low-sodium) or salt-free foods, and steering clear of caffeine and alcohol could help, but I am doing a vegan, salt free eating plan, and I don't do caffeine or alcohol in any form. Low blood pressure can aggravate balance problems and may be managed by drinking plenty of water, avoiding alcohol, and being cautious regarding the body's posture and movement, such as standing up slowly and avoiding crossing your legs when seated. I don't have any difficulty from that either.
I think in my case I lack reliable sensory input from the coordination of my vision, my inner ear balance and my proprioceptors (those sensors of position and movement in my feet and legs). Since good balance is so dependent on good muscle strength and joint mobility, my previous sedentary lifestyle of sitting for hours studying for my college classes have most likely compromised my strength and mobility causing my balance problem. As we humans get older it is a very common mistake to ignore our strength and mobility skills and make us ever so prone to falls. It is often said that after an elderly person falls, it is often a trip to the old age home that comes next! SO, I WILL BE WORKING MY BUTT OF DOING STAND-UP UNTIL I GET BACK MY BELOVED BALANCE SKILLS! YOU CAN BET ON IT!!!!