Objective: We evaluated cardiovascular autonomic reflexes and serum fibroblast growth factor 21 (FGF21), a surrogate marker of mitochondrial function, in a cohort of overweight and normal-weight adults (n = 42).
Methods: Indices of autonomic function were monitored during supine rest, autonomic reflex tests and submaximal clinical exercise test, with heart rate variables and blood pressure measured with an automatic system.
Results: Markers of sympathetic dominance were accentuated in overweight adults, including elevated resting low-frequency to the high-frequency ratio for heart rate variability (203 ± 227 vs. 96 ± 42; p = .01), and handgrip diastolic blood pressure (36 ± 15 mmHg vs. 25 ± 12 mmHg; p = .01). A weak non-significant trend has been found for a negative correlation between blood pressure responses to isometric handgrip test and FGF21 in the overweight group (r = -0.37; p = .09).
Conclusions: Excess body weight appears to trigger sympathetic overactivity in overweight adults, yet autonomic dysregulation might not be associated with notable changes in serum FGF21.
Keywords: Body mass index; FGF21; cardiovascular autonomic dysfunction; heart rate variability.