You have to listen. Your body knows best.
Last evening after after riding 40+ km after work, I made a cup of coffee and sat down to watch the last hour of the TDF that I had recorded earlier. Within 10 minutes I was fast asleep sitting up on the coach. I missed the finish.
Today, I left the office early ready to do my customary 50 km ride in the park before heading home. After only 10 km I was starving. My legs were trebling and I was light headed. In spite of having breakfast and an energy shake before heading out, I was done.
I stopped and had a veggie burger and a bottle of water. And, I rested for 45 minutes in the shade.
I wasn’t listening. My body was telling me to rest. Slow down. It has been unusually hot and humid this past week. I have kept up the same training schedule, slept less because of the heat and, eaten less. This has a cumulative effect. You would think I know better.
The ride today will be shorter and slower.
PedalWORKS 
My partner tends to nap abit more after a few hrs. of sustained cycling. Before it was harder cycling. Now it’s even after lighter cycling around the city.
It’s our age I guess.
Yup. Nothing wrong with that.