I saw some programme on iplayer where they compared muscle healing after exercise (running, in this case) between 3 groups. A control group, a group bathing in ice water, and a group bathing in hot water.
Turns out that both the hot or ice cold baths work nearly equally as well in healing. Far better than the control, with the ice water being marginally better, but only by around 2%. As long as the heat / cold is applied sufficiently long enough for it to penetrate to the muscles in question then both are good.
Edit: oh, but heat / cold "sprays" do absolutely nothing at all. Waste of money.
Negative, I am a meat popsicle.