 Study participants treated with the heatwraps also showed greater (138%) pain relief than those who received standard cold pack treatment, according to the study's research director, John Mayer, Ph.D.The study concluded that heatwraps were effective in the early treatment and prevention of Delayed Onset Muscle Soreness (DOMS)--soreness that occurs within one to two days of physical exertion.Thermacare heatwraps have been studied in 13 randomized controlled clinical trials for muscle pain relief efficacy.