‘Contrast baths’, in which the application of cold and heat to an injured area is alternated, are popularly believed to reduce oedema (tissue swelling) and relieve discomfort following an injury (Sullivan, J. & Anderson, S. (Eds.) (2000) Care of the Young Athlete. American Academy of Orthopaedic Surgeons). Is there any valid basis for this belief?
A trawl of the scientific literature on this topic using Medline uncovered just two articles in this area, and one of the articles was anecdotal in nature, with no rigorous, controlled testing of the efficacy of contrast baths. The other journal article described research carried out at the University of North Carolina in which 30 subjects with post-acute sprained ankles were assigned to either a cold (n = 10), heat (n = 10), or contrast-bath (n = 10) treatment group (‘Comparison of Three Treatment Procedures for Minimizing Ankle Sprain Swelling’, Physical Therapy, Vol 68 (7), pp1072-1076, 1988). Volumetric measurements of the subjects’ ankles were made in a specially constructed tank, before and after treatment. An increase in the amount of oedema was actually observed with all three treatments, but cold application was associated with the least quantity of swelling; contrast baths were no better than the direct application of heat when it came to controlling swelling.
This study is somewhat flawed, since there were no control individuals with whom the persons utilising the various treatments could be compared. Nonetheless, the research suggests that there is nothing particularly advantageous about contrast baths (especially when compared with the application of nothing but cold) in the treatment of sprained ankles or oedema in general. Interestingly enough, there also does not appear to be a single study in the scientific literature linking contrast baths with quicker recovery from injury or with a significant decrease in pain associated with an injury.