I would think immediately after a workout your levels would be depleted.
Theoretically, that depeltion would alert the HPTA that levels are low and muscles are broken down and need recovery and send down some LH to the testicles to ramp up the production of an increased level of T.
It is well known that high intensity workouts increase T production as well as
GH production.
GH production can be increased up to 500+% by using a sprint style of training.
How long this takes from the finish of the workout until the production increases is beyond me.