Objective: Handgrip exercise is an emerging strategy for resting blood pressure (BP) reduction requiring minimal time and exercise effort. However, the research literature is currently limited to handgrip protocol designs predominantly prescribing sustained grip contractions, with little assessment of alternative options. Furthermore, our understanding of the utility of handgrip exercise would be strengthened by an evaluation of the physiological mechanisms driving BP reductions and an assessment of the interindividual response variability. As such, this research was designed to perform an initial evaluation of the pragmatic effectiveness of a novel at-home, high-intensity, unilateral (nondominant) handgrip exercise training program in reducing resting BP, while simultaneously exploring mediators of BP change including a neurocardiac index of autonomic nervous control [heart rate (HR) variability], measures of arterial stiffness (radial augmentation index and carotid-radial pulse wave velocity), and cardiovascular reactivity to psychophysiological stressors.
Methods: Postmenopausal women were recruited to complete 8 weeks of handgrip exercise training. Aforementioned measures of resting BP and mediators of BP change were acquired at the midway point and end of training.
Results: All participants (n=17) completed training with high self-reported adherence (96.9%) and improvement in grip strength (2.7±2.4kg, P<0.05). Handgrip training reduced resting systolic BP (-5.1±7.7 mmHg, P<0.05) and improved HR complexity (sample entropy: 0.24±0.31, P<0.05), without significant changes to resting diastolic BP, HR, or arterial stiffness (all P>0.05).
Conclusion: This pilot study successfully shows the potential utility of high-intensity intermittent handgrip exercise for improvements in cardiovascular health among postmenopausal women, with additional research required to further explore the underlying physiological mechanisms driving such improvements.