Through personal experience and through my education as a Certified Athletic Trainer, I am very pro ice baths. Ice is a natural analgesic and anti-inflammatory. This can help to speed up the recovery process after a particularly hard bout of exercise. The recommended time for an ice bath specifically the lower body is 7 to 10 minutes at approximately 55 degrees Fahrenheit.
In the first 0 - 3 minutes you will feel the cold sensation. In the first 2 - 7 minutes the sensation will be a mild aching or burning. Then after the first 5 - 12 minutes you will have a mild anesthetic effect.