Cardiac Autonomic and Blood Pressure Responses to an Acute Bout of Kettlebell Exercise

Abstract

Increased blood pressure (BP) and autonomic dysfunction are independent risk factors for cardiovascular disease. Heart rate variability (HRV) is used as a measure of cardiac autonomic function in many research settings, including the evaluation of the autonomic control during and after physical activity. A prolonged sympathetic predominance and a slow parasympathetic reactivation contribute to a delayed BP and heart rate (HR) recovery after exercise which is thought to be associated with increased risk of acute cardiac events. Therefore, understanding the impact of various exercise modalities on the post-exercise autonomic modulation and BP would allow for appropriate exercise prescription in susceptible populations. Kettlebell (KB) training has become an extremely popular training modality for improving both muscle strength and aerobic fitness. However, the HRV and BP responses induced by an acute KB exercise session are currently unknown. PURPOSE: To evaluate the effects of an acute session of KB exercise on HRV and BP responses in healthy young adults. METHODS: 17 young healthy adults (M=10, F=7) completed a KB exercise or a no-exercise control trial in a randomized order. During the KB trial, participants completed twelve-30s sets of KB swings followed by 30 seconds of rest. Men and women used a 16kg and 8kg KB, respectively. Low-frequency power (LF), high-frequency power (HF), the LF to HF ratio (LF/HF), HR and BP were collected in the supine position at baseline, 3, 10 and 30 min after each trial. LF and HF were normalized to total power resulting in nLF, nHF and nLF/nHF. RESULTS: There were significant group-by-time interactions (P < 0.05) for nLF (sympathetic activity), nHF (vagal tone), nLF/nHF (sympathovagal balance), HR, systolic and diastolic BP. There were significant increases (P<0.01) in nLF, nLF/nHF and HR as well as significant decreases (P < 0.01) in nHF, systolic (~4mmHg) and diastolic (~3mmHg) BP for 30 min after KB compared to no changes after control. CONCLUSIONS: Our findings indicate that KB exercise increases sympathovagal balance 30 min post-exercise which is concurrent with a sustained hypotensive effect in young healthy adults. Further research is warranted to evaluate the potential clinical application of KB in populations that might benefit from post-exercise hypotension.