BACKGROUND: Whole-body cryotherapy (WBC) is used as a conditioning method for athletes. However, the scientific evidence for its effects is still insufficient. OBJECTIVE: To elucidate the effects of transient WBC on the expression of heat shock protein (HSP) 70 and the secretion of related hormones in humans. MATERIALS AND METHODS: The participants in this study were six healthy adult men. WBC was performed for 3 min in a booth at a temperature in the range of -150 to -120°C, and measurements were taken immediately before (Pre), immediately after (Post), and 60 min after WBC (Post60). For measurement of core body temperature (gastrointestinal temperature), participants ingested a capsule-type wireless temperature sensor. The body surface temperature was measured using a noncontact thermometer, and measurements were taken at four sites on the body surface (chest, abdomen, front of the thigh, and front of the lower thigh). Leukocyte count, lactate dehydrogenase, creatine kinase, hemoglobin, hematocrit, adrenaline, noradrenaline, cortisol, adrenocorticotropic hormone (ACTH), erythropoietin, and HSP70 in the collected blood were measured. RESULTS: The results showed a decrease in body surface temperature and an increase in noradrenaline and ACTH immediately after WBC. In addition, the core body temperature decreased 60 min after WBC, accompanied by an increase in HSP70 expression. CONCLUSION: WBC may increase HSP70 expression via noradrenaline and ACTH. The results of this study suggest the usefulness of WBC in triggering protein synthesis and the maintenance of immune function after training.