Can high-intensity interval training change cardiac autonomic control? A systematic review

Abstract

Background: High intensity interval training (HIIT) has been used as a cardiovascular exercise strategy to promote greater adherence in cardiovascular rehabilitation. However, little is known about the effect of this training modality on cardiac autonomic control. Objective: To perform a systematic review to evaluate the effects of HIIT on cardiac autonomic responses in humans. Methods: PEDro, SCOPUS and PubMed were searched from the inception to March 29th, 2018. Moreover, the methodological quality and statistical reporting from all eligible clinical trials were assessed by the PEDro scale. The articles were eligible if: The primary objective was related to the effects of HIIT on the cardiac autonomic nervous system. Outcomes evaluated were indirect measures of cardiac autonomic control, represented by HRV indexes. Results: The search strategies resulted in 339 citations and 2 additional citations were identified through other sources. After deleting the duplicate articles and revising the full text, 6 articles were included. Overall, the results showed an improvement in parasympathetic and/or sympathetic modulation after HIIT, when evaluated by linear and non-linear indexes of HRV. Conclusions: HIIT is a promising tool to improve the cardiac autonomic control, with more recommendation in healthy individuals and patients with metabolic syndrome.

Effects of a HIIT Protocol on Cardiovascular Risk Factors in a Type 1 Diabetes Mellitus Population

“…Previous studies have inquired about HIIT effects on HRV, but in people with different pathologies or even healthy individuals and with different methodologies, so comparisons must be taken with caution. Evidence from those studies also suggests tendencies of higher HRV median values of RMSSD (9.6-22%) and lower LF/HF (7.05-30%) [24], in line with our results. It is important to stand out that HIIT protocols used in those investigations ranged from 2 to 24 weeks and were performed in cycle ergometer and treadmill.…”

“…The large fluctuations in blood glucose levels associated with T1DM tend to place this population at an autonomic control dysfunction and in a reduced HRV in comparison with their healthy counterparts [22]. Given that physical exercise positively affects cardiac autonomic function in people with type 2 diabetes [23] and HIIT has been shown as a promising strategy to improve HRV in healthy individuals and patients with metabolic syndrome [24], we aimed to examine the effect of a HIIT protocol on HRV of a population with T1DM. Secondly, body composition is a traditional cardiovascular risk factor, and in the same way, obesity and overweight are dramatic increased in T1DM people, in fact, almost 50% of patients with T1DM are either overweight or obese [1].…”

Effects of high intensity interval training on neuro-cardiovascular dynamic changes and mitochondrial dysfunction induced by high-fat diet in rats

“…In this sense, by analyzing time-domain parameters of HRV, we can see that the high-fat diet was responsible for the development of autonomic dysfunction independent of physical training (HIIT). On the other hand, as reported previously, HIIT was able to promote benefits in autonomic function after 4 weeks of physical training compared to the control group [ 41 ]. These results explain the functional changes observed in the contractility and relaxation indexes of the heart, since autonomic dysfunction is one of the mechanisms associated with remodeling and myocardial dysfunction [ 42 ].…”

Effects of Different Training Interventions on Heart Rate Variability and Cardiovascular Health and Risk Factors in Young and Middle-Aged Adults: A Systematic Review

“…However, none of these studies used ECG, only chest belts for recording the NN intervals. As already mentioned previously, compared to continuous training, high intensities produce a stronger stimulus on nitric oxide syntheses, thus favoring the bioavailability of it and induce greater distensibility of the carotid artery, favoring baroreflex sensitivity (de Abreu et al, 2019 ). The results here also demonstrate that both women (Boutcher et al, 2013 ) and men (Heydari et al, 2013 ) can benefit from high-intensity training.…”

“…In contrast, low-intensity or low-volume training is not sufficient to significantly improve autonomic function (Martinmaki et al, 2008 ; Bond et al, 2009 ; Wu et al, 2011 ; McHugh et al, 2012 ; Brown et al, 2014 ). Compared to lower intensities, high-intensity sessions stimulate nitric oxide syntheses stronger, resulting in a stronger vagal activity (de Abreu et al, 2019 ). Furthermore, exercise training suppresses angiotensin II expression and thus improves cardiac vagal activity (Routledge et al, 2010 ).…”