While she was in hospice, I visited often. The day before she left the planet, I layed in bed with her. Her eyes were closed, she didn't move, and she had the death rattle (noisy breathing). I spoke to her, having no idea if she could hear me or not. I told her how wonderful she was, and how much she meant to me, and reminded her of fun times we had together.
Then, something inspired me and I said, "Hey! Are you just doing this to get out of exercise? Because if so, it's not going to work! So here we go. Exercise number one: lift a finger." After a few seconds, of nothing, I figured she either didn't hear me, or couldn't do it. Then she did it! She lifted a finger! Unsure if it was a coincidence, I said, "Okay! Exercise number two: lift an eyebrow." Again, it took a few seconds, but she did it! She really did it! I was so excited, I said "Great job! Exercise number 3: move your lips." Amazingly, she did it. I could hardly believe it. I told her she did a great job, and her workout was complete.
I'll never ever forget that. As I laughed, I told her how much I honored her for playing along, and for still having a sense of humor.
I will miss this dear person, very much. She was an absolute blessing to me.
So just think. If she can exercise while on her literal death bed, then you can do something too! The trick is to do what's appropriate for you. Go for it.