There are many benefits of applying cold water or ice to the body after it has experienced stress and strain, such as after a workout or race. Being cold makes your blood vessels contract which prevents swelling and bruising. It also numbs your nerve endings which provides you with instant pain relief. This is why we use ice packs when we get injured.
Exercise inflames the body and inflammation is never a good thing. Cold water acts as an anti-inflammatory and can help you to recover quicker after a workout. A very cold shower or ice bath could also reduce the DOMS (aching muscles) you experience after a workout as it speeds up the recovery process and helps the muscles to repair.
Why do athletes use ice baths?
Studies have shown that immersing yourself in an ice bath reduces the inflammation and swelling experienced after exercise. When you train, your muscles develop micro tears which is what then stimulates them to repair and grow stronger. Exposure to extreme cold such as that of an ice bath can help to repair these tears and speed up the recovery process.
There are many athletes around the world who use ice baths after a match or workout. GB heptathlete Jessica Ennis-Hill is even known to stand in a wheelie bin full of ice to help her legs recover!
Some more premium gyms offer steam rooms, saunas, and hot tubs for after your workout. While this may seem like it's just to relax, there could be some benefit to it. While exposure to cold reduces your blood flow and constricts blood vessels, exposure to heat does the opposite. So spending 20 or so minutes in a sauna post workout will increase the blood flow to your muscles. This can help to disperse any built up lactic acid and release it from the muscles. Not only this, hot water and steam relax your muscles and relieve body tension which can be perfect for unwinding after a furious workout.