I'm 67, but last week I didn't feel a day over 50. We had a tough deadline to meet, and several times I worked late, slept a few hours and got up early. There was a mass of detail to attend to, and it felt great to see my younger self kick in, stay awake and alert, to help our team achieve an excellent finish. I knew I would pay later.
I've been catching up on my sleep, but – days later – I know I'm still exhausted. I swim regularly, and today I got really exhausted in 35 minutes. Last weekend, before the big push at work, I swam 45 fast, effortless minutes. So what's going on?
The fascinating thing is that, when you fall back into old habits, your body can summon up the strength that goes with those habits, even if you really don't have that strength anymore. You remember how to behave, how to do the task, and how to summon the energy. If in fact your body's too old for that, you pay it back later, with a much longer recovery time. Next time you see an oldster not acting their age, amazing you with their resources, maybe that's what's happening. Keep an eye on them later. For example:
Wow, I am tired.