Having a shower perhaps after time working out (8)
I believe the answer is:
training
'working out' is the definition.
(training is a kind of working out)
'having a shower perhaps after time' is the wordplay.
'having a shower perhaps' becomes 'raining' (shower of rain).
'after' is a charade indicator (letters next to each other).
'time' becomes 't' (abbreviation).
'raining' put after 't' is 'TRAINING'.
(Other definitions for training that I've seen before include "Vocational education" , "Exercising" , "Regime" , "Doing exercise" , "practical instruction" .)