Separate and combined effects of cold dialysis and intradialytic exercise on the thermoregulatory responses of hemodialysis patients: a randomized-cross-over study

BACKGROUND: The separate and combined effects of intradialytic exercise training (IET) and cold dialysis (CD) on patient thermoregulation remain unknown. This study assessed the thermoregulatory responses of hemodialysis patients under four different hemodialysis protocols: a) one typical dialysis (TD) protocol (dialysate temperature at 37 °C), b) one cold dialysis (CD) protocol (dialysate temperature at 35 °C), c) one typical dialysis protocol which included a single exercise bout (TD + E), d) one cold dialysis protocol which included a single exercise bout (CD + E). METHODS: Ten hemodialysis patients (57.2 ± 14.9 years) participated in this randomized, cross-over study. Core and skin temperatures were measured using an ingestible telemetric pill and by four wireless iButtons attached on the skin, respectively. Body heat storage (S) calculated using the thermometric method proposed by Burton. RESULTS: The TD and TD + E protocols were associated with increased S leading to moderate effect size increases in core body temperature (as high as 0.4 °C). The low temperature of the dialysate during the CD and the CD + E protocols prevented the rise in S and core temperature (p > 0.05), even during the period that IET took place. CONCLUSIONS: TD and IET are accompanied by a moderate level of hyperthermia, which can be offset by CD. We recommended that CD or with IET can prevent the excessive rise of S. TRIAL REGISTRATION: Clinical Trial Registry number: NCT03905551 (clinicaltrials.gov), DOR: 05/04/2019,