Ice baths have been a staple method of recovery for distance runners for many years. The idea behind an ice bath is that you submerge the lower half of your body in cold water after a workout, which reduces the amount of inflammation in your legs and speeds recovery.
For a long time, it seems no one thought it necessary to study the effects cold water immersion on the inflammatory system. Recently, though, the effectiveness of ice baths has come into question in the scientific community. Ahead, I will lay out a few of the prominent studies for and against the use of ice baths as a recovery tool.
One prominent study in support of ice baths was completed by the Cochrane Bone, Joint and Muscle Trauma Group in 2012. This review incorporated 366 total participants over the course of 17 trials. It compared muscle soreness after workouts between individuals who engaged in cold water immersion post-workout versus those who engaged in passive recovery (doing nothing). The study concluded that there was reduced soreness in the groups that took ice baths as compared to the groups that did not.
This study had several short-comings, though. First, its sample size was small by scientific standards. Also, it did not compare the effectiveness of ice bath recovery to the effects of other forms of recovery, such as light jogging or muscle compression. Finally, it did not attempt to note optimal methods for ice bathing (such as the most effective water temperature or length of time spent in the bath). Nonetheless, this study shows that individuals felt better recovered after ice bathing than those who did nothing to recover.
There are several studies, though, that refute the points made by the Cochrane Group. One study found that cold water immersion was not more effective in reducing inflammation than active recovery (a light cool down after intense exercise). One flaw with this study is that it did not analyze the effect of combining a light cool down with also taking an ice bath.
Another research group goes one step further and questions whether reducing inflammation is even beneficial after a workout. This study notes that the inflammatory process is the body's natural mechanism for recovery and suggests that further research must be done to determine whether inhibiting the inflammatory process is useful or detrimental to recovery. While this study does not prove or disprove anything definitively, it is thought-provoking and hopefully studies will be done in the future to expand upon its theory.
At the end of the day, it appears that more research must be done before we have a scientific consensus about the effectiveness of ice bathing. In the meantime, if you feel that ice bathing benefits you, then hop in a cold bath after a workout.
Most athletes keep their ice baths in between 50-59 °F and sit for 10-15 minutes. If that seems miserable and you don't want to ice bathe, then don't. Cold water immersion has helped many runners feel fresh and recovered, but science has a long way to go before coming to an agreement about whether ice baths are truly useful as a recovery tool or whether their benefits are no more than a placebo.