Cold is used to counter inflammation, to encourage vasoconstriction and to numb pain.
Ice Bath–> Many athletes swear by the postworkout ice bath which say helps reduce inflammation and move waste products from the muscles. If you live near the ocean, a quiet river, or a stream you may have natural cool baths handy. After a hard or long workout that has created trauma in your legs is when an ice bath can be useful. Long runs for two hours or longer or a 90 minute run with intensity calls for ice baths. The intensity of sitting in the cold usually grows for a few minutes because you’re body is responding by constricting the blood vessels, moving fluid away from the skin and toward the core. There’s no need to remain in for more than 20 minutes. The standard protocol is to apply ice for 10-15 minutes and sometimes to repeat after 20 minutes off up to 3 times a day.
Many cultures have long used heated rooms and baths for therapeutic treatment. In a heated environment, blood flow to the skin is increased, along with perspiration. For athletes, cold is more appropriate then heat. Spending time in the sauna can be beneficial because it’s been shown to reduce blood pressure in hypertensive subjects and help those with respiratory diseases. Be sure to stay hydrated during and after the visit to a sauna. A whirpool or hot tub combines warm temperatures with the benefits of water therapy. The hydrostatic pressure of water is beneficial for reducing swelling and the movement of water over the body will relax both muscles and mind while increasing circulation. Heat can loosen stiff muscles and increase circulation.
Source: Rountree, Sage Hamilton. The Athlete’s Guide to Recovery: Rest, Relax, & Restore for Peak Performance. Boulder, CO: VeloPress, 2011. Print.