By the third hour my arms are shaking and the guys next to me are still moving like it is nothing. I try to keep pace but I am gasping and soaked and falling behind. At the end of the shift I sit in my car too tired to drive, wondering how long I can pretend my body can do this.
More people experience this than they realize.
The physical work is more than your body can keep up with.
If this sounds familiar, the Library can help you find the bigger picture.