Great posts everyone Note to Jeffrey Hill…I am awe of your cardio program– most impressed. I went back to the YMCA after covid and was shocked that my safe maximun heart rate did a nose dive so much so that I had to stop at 90 bpm after 4 minute workouts. Six months later I can go comfortably at about 100 bpm for 30 minutes on the bike. I am elderly with advanced Parkinsons and have many off periods. My question is, ‘Should I quit while I am ahead”. heart appears to be in great shape, neurologist said just do what you can. Is it dangerous sometime to just push too far….I do 10 hours a week at the Y. Thanks in advance for any advice. Happy New Year to all! Judy G