Heat and cold therapy reduce pain in patients with delayed onset muscle soreness: A systematic review and meta-analysis of 32 randomized controlled trials

The aim of this review and meta-analysis was to evaluate the effect of heat and cold therapy on the treatment of delayed onset muscle soreness (DOMS). We followed our protocol that was registered in PROSPERO with ID CRD42020170632. A systematic review and meta-analysis of randomized controlled trials (RCT) was conducted. Nine databases were searched up to December 2020. Data was extracted from the retained studies and underwent methodological quality assessment and meta-analysis. A total of 32 RCTs involving 1098 patients were included. Meta-analysis showed that, the application of cold therapy within 1 h after exercise could reduce the pain of DOMS patients within 24 h (≤24 h) after exercise (SMD -0.57,95%CI -0.89 to −0.25, P = 0.0005) and had no obvious effect within more than 24 h (>24 h) (P = 0.05). In cold therapies, cold water immersion (SMD -0.48, 95%CI -0.84 to −0.13, P = 0.008) and other cold therapies (SMD -0.68, 95%CI -1.28 to −0.08, P = 0.03) had the significant effects within 24 h. Heat treatment could reduce the pain of patients. It had obvious effects on the pain within 24 h (SMD -1.17, 95%CI -2.62 to −0.09, P = 0.03) and over 24 h (SMD -0.82, 95%CI -1.38 to −0.26, P = 0.004). Hot pack effect was the most obvious, which reduced the pain within 24 h (SMD -2.31, 95%CI -4.33 to −0.29, P = 0.03) and over 24 h (SMD -1.78, 95%CI -2.97 to −0.59, P = 0.003). Other thermal therapies were not statistically significant (P > 0.05). Both cold and heat showed effect in reducing pain of patients, however there was no significant difference between cold and heat group (P = 0.16). The current evidence indicated that the application of cold and heat therapy within 1 h after exercise could effectively reduce the pain degree of DOMS patients for 24 h cold water immersion and hot pack therapy, which had the best effect, could promote the recovery of DOMS patients. But more high-quality studies are needed to confirm whether cold or heat therapy work better. ●Application of cold therapy within 1 h after exercise, could effectively reduce the pain level of DOMS patientshad the best analgesic effect within 24 h (≤24 h) after exercise and had no obvious effect on reducing pain level in patients more than 24 h (>24 h)。●In cold therapy, cold water immersion and other cold therapy had the significant effects within 24 h and had no obvious effect on pain over 24 h.●The application of heat treatment within 1 h after exercise could effectively reduce the pain level of pati