the exercise will have helped with your stiffness.
the F…fatigue (it’s vulgar language that i use) will have kicked in too.
so it’s a case of “shall i alleviate my stiffness and stay awake?” or “shall i stay awake a little longer with all my stiffness?”
my poor mum had bad arthritis and had medication for it but she also has an hiatus hernia which was made worse by the arthritis medication. so she had a similar decision to make each morning.
why not try 4 lengths? 2 lengths?
if you can find the most you can do without the rest of your day going to pot, you’ll be able to gradually increase it.
good luck and happy new year to you