Introduction: Cryotherapy is a recovery technique that involves the use of a cold substance. It is most commonly used in sports rehabilitation; however, the data on the use of cryotherapy as a strategy for faster recovery after aerobic exercise is conflicting. This systematic literature review therefore aimed to analyse the results of relevant up-to-date scientific studies on the effectiveness of cryotherapy in the recovery of healthy adults after aerobic exercise. Methods: This master’s thesis is a systematic literature review of randomized controlled trials or non-randomized controlled trials published in peer reviewed journals after 2011. Searched databases include PubMed, CINAHL and PEDro. Results: The inclusion criteria were met by 13 studies published between 2011 and 2023. The included studies measured subjective and objective recovery parameters or a combination of both. A total of 18 outcome measures, or recovery parameters, were identified, 3 of which were subjective and 15 objective. 8 different kinds of cryotherapy interventions were identified: cold-water showers, cold water immersion, whole body cryotherapy, cooling vests, phase-change material, ice slurry consumption, cooling bands and a hand-cooling unit. Effects were tested after aerobic exhaustion training in populations of runners, trained cyclists, soccer players and firefighters. Effects were predominantly beneficial for core body temperature, heart rate and delayed-onset muscle soreness. Cooling vests and cold water immersion produced clinically significant reductions in resting skin temperature (p < 0.01). Ingestion of crushed ice significantly promoted recovery of core and skin temperatures (p < 0.05). Core temperature values were also significantly lower when using phase-change material. Heart rate decreased significantly faster with the cold-water shower at the first 30-min recovery time point (p < 0.01). Cooling bands significantly reduced heart rate during recovery (p < 0.05). When using phase-change material, heart rate was significantly lower at 10 and 20 minute time point of cooling (p < 0.001). With whole body cryotherapy, delayed-onset muscle soreness decreased after the first whole body cryotherapy session after 1 hour. Using cold water immersion and whole body cryotherapy, increased delayed-onset muscle soreness was present in all groups from baseline up to 24 hours, but lasted longer in the placebo group, up to 48 hours. Results remain conflicting for c-reactive protein levels, blood creatine kinase and muscle strength. Further insight is needed for inflammation markers tumor necrosis factor alpha, interleukin 6, interleukin 10, interleukin 1r alpha and interleukin beta as the data is not statistically significant. Discussion and conclusion: In the population of healthy adults, cryotherapy modules remain a safe recovery method. Overall, cryotherapy may serve as an efficient strategy to accelerate recovery in sport. Additional research is needed with bigger population samples as well as to elucidate the sex differences in response to cryotherapy.
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