Stress kills.
Exercise, like other medicines, has a therapeutic dose.
A question I get all the time:
"I have a busy life, and I only have a few hours to train each week. Shouldn't I make them count by going harder?"
No.
See, your body doesn't separate training stress from life stress.
If you're carrying a full-time job, poor sleep, family responsibilities, and financial stress, your "stress bank account" is already running too low for high-intensity training....
You're broke!
Your adaptation reserves are already being spent!
My latest...
Why Too Much Intensity Breaks Athletes:
Understanding Adaptation Energy