Effects of whirlpools on workouts?

Factual Questions
1

Got a gym membership to a place that has a nice whirlpool/hot tub/whatever they’re called. I was wondering what the physiological effects would be on using it before and after workouts.

I’ve been spending 10 minutes in it after workouts to relax - and I find myself extremely weak when I get out - completely drained. I don’t know if that’s positive, negative, or either.

I’ve considered spending 5-10 minutes beforehand too to loosen up, but I don’t know if that would have benefits or not.

What are the general physiological effects, and what are they specifically pertaining to excercise? Are there benefits, or negatives?

2

That wouldn’t work. You’ll get your body temperature raised slightly, but none of the other, more important effects of a warmup.

3

I wouldn’t do it instead of warming up, but in addition to.

I thought I’d read somewhere that a high external temperature causes increased bloodflow among other things - that seems like it would be beneficial, if so.