We all have "rocks" in our heads. They are in our inner ear and help our bodies determine which way is up. They are essential for balance.
Sometime after age 40 those "rocks" begin to fall apart. It is a slow process and we barely notice. But eventually, sometime in our 60s, 70s, or 80s, we begin to lose our balance for no good reason. We fall in the shower, or worse, fall down stairs. We fall down trying to enter Air Force One.
My youngest brother falls down all the time and needs help to get back up. One time he fell down when he got up to let his cats go outside. He stayed on the floor for several hours until someone came home and helped him up. He is not quite 60.
A few minutes ago, I got up to get another cup of coffee. I didn't get up quickly, there was nothing unusual about getting up this time. But I had the most peculiar sensation of stumbling or falling. I didn't. But I could have.
I addressed this in one of the medical books I wrote a few years ago while having never experienced it myself. From my research people with this issue tend to self-isolate for fear of falling down in public.
It is one more thing to be mindful of.