Hi Margaret ob
Fellow approaching 80, too. Lived thru three real ups and downs in life. So far without any meds, surgeries, tests bcause I suppose I've tried to Live Life first in all its areas of interest to humans starting with playful exertions rather than that strange word 'exercise' eating with full attention to taste and feel and smell and it resulting in good restful sleep and having my thoughts (expectations, feelings, attitudes, goals...) whetted out with a good dose of what life really is -- no certainties, lots of surprises in worklife, family, friendships, neighbors and nations. Likely with this attitude, I have ended up mostly medical troubles-free
and most of all Looking Forward to what I'd Want to do next day/week or year. Some call it Purposeful life.

Actually purpose seems to be the most critical factor in our lives-with-no-guarantees. Patrick Hill of Washington State univ of St Louis has done studies going back to decades.
Good luck in this sometimes hard but always surprising universe!