Every Saturday At The Y

Today was like every Saturday.
By 7AM I've fed the cats and am deciding: drink coffee in the recliner or go back to bed?
No, I've got my 8 o'clock at the Y.
But what if it's the scary instructor? It's probably the scary instructor. What difference would it make to skip just this once?
What if I just go there to see my friends? I don't actually have to do anything.
Sure enough, it's the scary instructor. He's got biceps bigger than my calves and the endurance of someone in his 20s, which he is and I am not.
It's too late to go back. I lay out my gear, hydrate thoroughly, and wait for it.
I concentrate on breathing as we go. It helps to growl when we reach an absurd number of reps. I've heard yogi call this "lion breath" but it's really just growling. The instructor does not seem intimidated.
Bilateral symmetry is a problem. When we tire out a muscle group on one side, do we stop? No! He makes us flop over and do the same thing on the other side! When will we learn?
Class is tough but not as tough as it was this time last year. He must be slacking off. I've had to go up a size in weights to really feel it.
A funny thing always happens half way through. I get a feeling of distress from whatever muscles I'm working - not pain, just a feeling that there's nothing left so it's time to stop, the "Check Engine" light is on, there are no more fumes in the tank - but I also get a sense of well being.
Could it be that my body, which spends the work day sitting at a desk, actually likes physical activity?
More likely I'm just light-headed.
Then it's over. My jersey is completely soaked.
I say hi to my friends, thank the instructor for the class, and walk out with a complete sensation of relaxation throughout my frame.
It's only 9AM. I've got the whole weekend ahead and a happy body.
Maybe next Saturday I'll sleep in. What difference would it make?