Blunted cerebral hemodynamic responses to incremental exercise in patients with end-stage renal disease

The aims of this study were to compare cerebral hemodynamics and maximal oxygen uptake (VO_2peak) in patients with end-stage renal disease (ESRD) vs. age-matched healthy controls during maximal exercise.

Twelve patients with ESRD and twelve healthy adults (CTR group) performed exhaustive incremental exercise test. Throughout the exercise test, near-infrared spectroscopy allowed the investigation of changes in oxyhemoglobin (∆O₂Hb), deoxyhemoglobin (∆HHb), and total hemoglobin (∆THb) in the prefrontal cortex.

Compared to CTR, VO_2peak was significantly lower in ESRD group (P < 0.05). Increase in ∆THb (i.e., cerebral blood volume) was significantly blunted in ESRD (P < 0.05). ESRD patients also had impaired changes in cerebral ∆HHb and ∆O₂Hb during high intensity of exercise (P < 0.05). Finally, no significant correlation was observed between VO_2peak and changes in cerebral hemodynamics parameters in both groups (All P > 0.05).

Maximal exercise highlights subtle disorders of both hemodynamics and neuronal oxygenation in the prefrontal cortex in patients with ESRD. This may contribute to both impaired cognitive function and reduced exercise tolerance throughout the progression of the disease.