Hemodialysis disrupts basic sleep regulatory mechanisms: Building hypotheses

Background: The proposition that hemodialysis may induce alterations in the sleep-wake cycle is based on two clinical observations: (a) Patients on dialysis frequently sleep during and after dialysis, and (b) the procedure often is associated with temperature elevations. A review of pertinent literature showed that sleepiness and temperature are physiologically related, and that these two variables are important indicators of sleep and circadian regulatory processes. Objectives: To describe possible associations among hemodialysis, body temperature, and sleepiness; to assist in building hypotheses; and to provide direction for future research. Methods: Three exploratory studies were performed to investigate (a) dialysis-associated elevations in body temperature, (b) changes in body temperature patterns across the day, and (c) alterations in daytime sleepiness. Results: The current study demonstrated that many patients manifest dialysis-associated episodic elevations of body temperature, changes in the circadian pattern of body temperature, and increases in daytime sleep propensity. in the context of the Two-Process Model of Sleep Regulation, these alterations provide a parsimonious explanation for the poor subjective sleep quality, prolonged sleep latency, and daytime sleepiness reported by these patients. Conclusions: These preliminary studies lead to the suggestion that hemodialysis may disrupt basic sleep regulatory mechanisms, and that further investigation in this area is warranted.