Cold and hot therapy

Question

First off I'm not looking for advice as I have no interest in using either of the I'm just curious about the purpose of them.

I've heard hot or cold therapies, and sometimes both, are used after exercise to improve recovery, but that raises some questions for me as it seems to be a contradiction.

Hot therapy dilates blood vessels and increases blood flow and cold therapy constricts blood vessels and decreases blood flow. If increased blood flow is good then, logically, shouldn't a decrease be bad, and vice versa? How can both be beneficial?

Answer 1

Both are similarly effective at reducing delayed onset muscle soreness.¹ The most likely mechanism through which they have this effect is placebo, which would allow both to be beneficial, despite them being complete opposites of each other.

Maybe this guy was onto something.