What word conveys the opposite state of "recovery"? [closed]

If one can be in a state of "recovery" what word conveys an opposite state?

I'm looking for a word that conveys that someone is in a state where they're exerting themselves through physical action. Instead of being in a state of rest—building strength and regaining energy—they're losing it through physical action.

Thank you!

Deterioration

From thesaurus.com, the antonyms of recovery are:

deterioration

relapse

Since "relapse" implies a period of recovery, I've discarded it.

Where "recovery" implies getting better, "deterioration" implies getting worse, although the mechanism of getting worse isn't explicit. In your example, it could be "wilful deterioration".

exertion noun
: the act or an instance of exerting
especially : a laborious or perceptible effort
^{https://www.merriam-webster.com/dictionary/exertion}

You are in a state of exertion while you are using energy.

"Decline".

From Merriam-Webster:

: to tend toward an inferior state or weaker condition his health declined Employee morale declined after the layoffs.