Optimizing whole-body cryostimulation exposure duration: Effects of age, sex, and body mass index in achieving target skin temperature

The optimal Whole-body cryostimulation (WBC) exposure duration to reach the target skin temperature may vary depending on individual factors such as age, sex, and body mass index (BMI). Maintaining skin temperatures below 13.6°C is necessary to trigger significant cold-induced analgesia. The aim of our study is to investigate how these variables influence the duration required to reach the analgesic threshold temperature of 13.6°C during WBC. A randomized cross-over controlled trial was conducted with 90 healthy participants, categorized by age, sex, and BMI. Each participant underwent two sessions: a 4 min WBC exposure at -50°C and a control session. Skin temperature was measured using a thermal imaging camera before, during and after cold exposure. Significant differences in skin temperature were observed between groups. Among young participants, normal-weight men required 4 minutes of exposure to reach the analgesic threshold (<i>p</i> < 0.05), while normal-weight women reached it in 3 minutes (<i>p</i> < 0.01). Overweight young men needed 3 minutes and 30 seconds (<i>p</i> < 0.001), whereas overweight young women reached the threshold earlier, at 2 min and 30 s (<i>p</i> < 0.01). For senior participants, both normal-weight men and women reached the analgesic threshold at 3 minutes of exposure (<i>p</i> < 0.001). In contrast, overweight senior men and women needed only 2 minutes and 30 seconds to reach the target skin temperature (<i>p</i> < 0.01). The optimal WBC exposure duration for achieving analgesic effects varies significantly depending on individual characteristics, suggesting that WBC protocols should be tailored to maximize therapeutic benefits.