[lightburst]

I've read that cold baths after exercise is somehow a good thing, and pro athletes do it too. I don't particularly know what's really going on in there but wouldn't starving muscles of oxygen be harmful? After all, it's a survival function that blood go away from extremities when on low temperatures. Wouldn't a cold bath(or ice bath, even worse) 'kill' starving muscles? I personally wouldn't like to be suffocated.

[Perpetual Motion]

When you exercise lactic acid is shifted into your muscles, i believe getting a cold shower gets this stuff out.

that's the only reason i can see behind it.

[Schrödinger's hat]

I have seen this both as recommendation from coaches/trainers and empirical studies.
I don't know the mechanism behind it, but in addition to Perpetual Motion's suggestion, here is some conjecture:

Cold fluid dissolves gas more readily, perhaps CO2 or oxygen transport into and out of the cells is the limit rather than what the blood can carry? In this case cooling could be beneficial.

If the body needs to perform some exothermic (heat releasing) reaction in order to recover the ATP or do something with some other chemical in the muscles it could be limited by the temperature (ie. more heat would mean more damage so it slows the rather of the reaction). If this somehow resulted in the muscles spending longer metabolizing anaerobically it could result in more atp.

Most proteins are very temperature sensitive. Some of the damage to muscles in exercise could be related to the increased temperature (not just lactic acid). Ice baths would stop this if it were occurring.

[brodmannstwentysecond]

A trainer explained this to me once, but I don't know how much of his explanation was a guess. Here's the condensed version though:

Working out causes swelling, which impedes blood flow. Skin contact with cold surfaces (i.e., water) decreases swelling, which increases blood flow.

As mentioned, a decrease in blood flow can preserve internal body heat, which eventually becomes a priority in a cold environment. The idea is that for the few minutes they spend in the bathtub, the physiology of an intense athlete has precisely the opposite priority.

[PhDwannabe]

Quote

When you exercise lactic acid is shifted into your muscles, i believe getting a cold shower gets this stuff out.<br style="font-size: 13px; line-height: 16px; background-color: rgb(248, 250, 252); "><br style="font-size: 13px; line-height: 16px; background-color: rgb(248, 250, 252); ">that's the only reason i can see behind it.

Not quite. Lactic acid is produced by your muscles. There's been a view of lactic acid as a poisonous byproduct of strenuous muscle activity that, if it sits around too long, damages muscles and causes fatigues, soreness, etc. And we'd best do things to get it out--stretching, massages, cool-downs, tons of water. (It's not unlike the similar sort of toxin/flush paradigm you see in colon "cleansing" products, which are victims of a similarly erroneous view of how the digestive system works.) Long story short, for the last decade or so, plenty has come out which seriously damages the lactic acid hypothesis. See this review, or this, geared a little more towards the layman, if you're interested.