I'm 51. In my head I still feel young. But then I look in the mirror and see a white beard, white chest hair, sagging jowls, crow's feet, a bald spot and graying temples. It is really depressing.
I look in the medicine cabinet and I see blood pressure meds, and stool softeners.
Vigorous workouts tend to result in some form of pain or injury.
If I shave and wear a hat, people think I'm in my late 30s. But then I'll do things like groan when standing up from a seated position which is a dead giveaway.
When despondent about getting older just remind yourself of the alternative. And enjoy your relative youth to the fullest.
I'm sure there are many 81 year olds who would snap at the chance to go back to being 51 again. It's all relative.