The Benefits of Short Immersion in the Cold

People who go swimming have an improved immune function, but that improvement is not limited to people who go outdoor swimming. Measures of markers of immune function seem to suggest that if there's going to be a benefit to going into the cold, it arises from a shorter immersion rather than a longer one. If you're staying long enough for deeper tissues to call and to start moving towards hypothermia then actually that could be detrimental.