Hi Siobhan,
Here at the hotel before we check out and go the last leg of our journey to begin our NC vacation, I did 47 minutes on their elliptical.
Funny thing was the machine kept telling me to slow down so I could stay at my target heart rate. I did not listen to the machine, I know bad me.
Sometimes extended rests are what our bodies need, and yes, age has a lot to do with it.