Abstract 4347706: Acute Effects of Isometric Handgrip Exercise on Cardiac Baroreflex Sensitivity in Chronic Kidney Disease

Background: Patients with chronic kidney disease (CKD) exhibit impaired spontaneous cardiac baroreflex sensitivity (cBRS) that can contribute to poor blood pressure (BP) control and increased cardiovascular risk. Emerging evidence suggests that isometric handgrip (IHG) exercise may acutely enhance cBRS in various populations; yet its effects in patients with CKD remain underexplored. Aim: Therefore, this study aimed to investigate whether an acute IHG session improves cBRS in patients with CKD. Methods: Twelve patients with CKD (59 ± 11 years; 67% male; eGFR: 40 ± 7 mL/min/1.73m 2 ) participated in a randomized crossover study, performing four sets of 2-minute IHG exercise at either 30% (experimental) or 3% (sham) of maximal voluntary contraction with their dominant hand. Beat-to-beat heart rate (HR) and arterial BP were monitored using electrocardiography and finger photoplethysmography before IHG, and 30 min after IHG. Respiratory rate was assessed using a thoracic belt secured around the abdomen. Spontaneous cBRS was assessed via the sequence technique. Results: Spontaneous cBRS significantly increased following IHG exercise ( P = 0.01 vs rest). This increase persisted at 10-, 20- (Δ18% ± 4%, Δ18% ± 5%, both P < 0.02 vs rest), but not at 30-minutes post-exercise (Δ13% ± 6%; P = 0.35 vs rest). Conversely, there was no change in cBRS after sham exercise (all, P > 0.311 vs rest). HR decreased following IHG, reaching statistical significance at 30 minutes post-exercise (10 min: Δ-1 ± 2 bpm, P = 0.47 vs rest; 20 min: Δ-1 ± 2 bpm, P = 0.16 vs rest; 30 min: Δ-2 ± 2 bpm, P = 0.02 vs rest). Conversely, there were no changes in cBRS or HR after sham exercise. Respiratory rate remained unchanged throughout both conditions (all P > 0.24). Conclusion: These preliminary findings suggest that a single session of IHG exercise acutely enhances cBRS in patients with CKD. Collectively, this study indicates IHG exercise as a potential non-pharmacological strategy to improve autonomic function and cardiovascular health in CKD.