Cerebral oxygenation during exercise deteriorates with advancing chronic kidney disease

Area of Science:

• Nephrology
• Neurology
• Exercise Physiology

Background:

• Cognitive impairment and exercise intolerance are prevalent in chronic kidney disease (CKD).
• Cerebral perfusion and oxygenation are critical for cognitive function and exercise capacity.
• The impact of CKD stage on cerebral oxygenation during physical stress is not well understood.

Purpose of the Study:

• To investigate changes in cerebral oxygenation during mild physical stress across different stages of CKD.
• To explore the relationship between CKD severity, cerebral oxygenation, and cognitive/physical function.

Main Methods:

• Ninety participants (CKD stages 2-4 and controls) performed a 3-minute intermittent handgrip exercise.
• Cerebral oxygenation (oxyhaemoglobin, deoxyhaemoglobin, total haemoglobin) was measured using near-infrared spectroscopy.
• Cognitive status, physical activity, microvascular/macrovascular function were also assessed.

Main Results:

• Cognitive function, physical activity, and handgrip strength declined with advancing CKD stages.
• Cerebral oxygenation response (oxyhaemoglobin) significantly decreased with increasing CKD severity.
• Lower estimated glomerular filtration rate (eGFR) was independently associated with reduced cerebral oxygenation during exercise.

Conclusions:

• Advancing CKD is associated with diminished brain activation during mild physical tasks, indicated by reduced cerebral oxygenation.
• Impaired cerebral oxygenation may underlie cognitive deficits and exercise intolerance observed in CKD.
• eGFR is a key determinant of cerebral oxygenation response during physical stress in CKD.