Sabino-Carvalho JL; Department of VA Health Care System, Decatur, GA.
Li S; Mekonnen E; Mammino K; Nocera JR; Park J

Medicine & Science in Sports & Exercise. 57(12):2621-2629, 2025 Dec 01.
VI 1

PURPOSE: Parasympathetic reactivation is essential for the rapid decrease
in heart rate following exercise and delayed heart rate recovery (HRR)
post-exercise is linked to poor clinical outcomes. Chronic kidney disease
(CKD) is associated with autonomic dysfunction including reduced
parasympathetic activity. Exercise training may improve parasympathetic
reactivation. Therefore, this study aimed to test whether CKD patients
experience delayed HRR due to impaired vagal reactivation and if 12 wk of
aerobic exercise can improve HRR.

METHODS: Twenty-seven CKD patients (stages III and IV, estimated
glomerular filtration rate 15-59 mL.min -1 .1.73 m -2 ) and 18 age-matched
controls underwent cardiopulmonary exercise testing. HRR was assessed
through heart rate decay (HRR60s) and heart rate variability (HRV) during
the first 60 s of recovery. Recovery kinetics were modeled to calculate
the time constant ( tau ). CKD patients were then randomly assigned to
aerobic exercise or non-aerobic stretching interventions for 12 wk (3 d.wk
-1 ), and cardiopulmonary exercise testing was repeated post-intervention.

RESULTS: CKD patients exhibited significantly blunted HRR60s
(DELTAHRR60s: -11 +/- 4 vs -17 +/- 6 bpm, P = 0.001) and a longer recovery
time constant ( tau : 142 +/- 33 vs 116 +/- 21 s, P = 0.004) compared with
controls. HRV indices increased less post-exercise in CKD patients
compared with controls (DELTARMSSD: 0.3 +/- 1 vs 1.6 +/- 1 ms, P = 0.001).
Twelve weeks of aerobic exercise did not improve HRR60s (DELTAHRR60s: pre
-12 +/- 4 bpm vs post -12 +/- 7 bpm, P = 0.971) or HRV indices (all P >
0.108).

CONCLUSIONS: CKD patients have decreased HRR post-exercise due to
impaired cardiac vagal reactivation. Twelve weeks of aerobic exercise
training did not improve cardiac vagal reactivation. Future studies should
explore different exercise modalities and manipulate training variables
such as intensity, volume, and frequency to assess their potential impact
on cardiac vagal reactivation in patients with CKD.