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

Abstract

Introduction: Heart rate variability (HRV), the beat-to-beat variation of adjacent heartbeats, is an indicator of the function of the autonomic nervous system (ANS). Increased HRV reflects well-functioning of autonomic control mechanism and cardiovascular health. The aim of this systematic review is to provide a systematic overview of the effects of different physical training modalities on resting HRV and cardiovascular health and risk factors (i.e., baroreflex sensitivity, body fat, body mass, body mass index, blood pressure, heart rate recovery, VO2 max, and VO2 peak) in young and middle-aged (mean age of the studies samples up to 44 years), healthy adults.Methods: A systematic review in accordance with the PRISMA guidelines was performed. Studies investigating the effects of different physical interventions (endurance, resistance, high-intensity, coordinative, or multimodal training) on HRV were included. Trials were considered eligible if the intervention lasted for at least 4 weeks and participants were regarded as general healthy. Five electronic databases were searched from 2005 to September 8th, 2020. The methodological quality of eligible studies was assessed by two study quality and reporting assessment scales (TESTEX and STARDHRV). PROSPERO registration number: CRD42020206606.Results: Of 3,991 retrieved records, 26 were considered eligible and analyzed. Twelve studies used an endurance training (of which three included high-intensity sessions), six studies resistance training, four studies coordinative training, two studies high-intensity training, and two studies used a multimodal intervention. Overall, the results showed for all types of intervention an improvement in linear and non-linear HRV parameters and cardiovascular health and risk factors. However, quality assessment revealed some methodological and reporting deficits.Conclusion: This systematic review highlights the benefits of different types of physical training interventions on autonomic function and health parameters in young and middle-aged, healthy adults. In conclusion, higher training intensities and frequencies are more likely to improve HRV. For future studies, we recommend adhering to the criteria of methodological standards of exercise interventions and HRV measurements and encourage the use of non-linear HRV parameters.

Effects of Different Exercise Interventions on Cardiac Autonomic Control and Secondary Health Factors in Middle-Aged Adults: A Systematic Review

“…Additionally, endurance training seems to be appropriate to reduce RHR. The current findings are in line with previous reviews showing beneficial effects of endurance training on cardiac autonomic control [41,42]. The results suggest that at least three training sessions per week are necessary to induce HRV changes.…”

“…There were no changes obtained with a periodized intervention [3,55], nor with a constant intensity throughout the intervention [61]. This finding contradicts previous reviews showing beneficial effects in young adults [41,69]. Two weekly training sessions are probably not enough to elicit changes in autonomic modulation.…”

“…Furthermore, resistance training is recommended for increasing muscular strength, bone mass, improving quality of life, and reducing cardiovascular disease risk as well [14]. To improve procedure of the current review follows a previous review of the same authors considering young adults [41]. As a preservation of the adaptability of the cardiovascular system in older adults is assumed [49] and regular physical activity is positively associated with autonomic function [50], we hypothesized beneficial effects of physical interventions on HRV and secondary health factors in healthy middle-aged adults.…”

Heart Rate Variability Reflects Similar Cardiac Autonomic Function in Explosive and Aerobically Trained Athletes

“…Other short-term high-intensity exercise programs have elicited a training effect on LF, HF, and LF/HF [23]. Studies tend to agree that both extended-duration moderate and short-duration intense exercise training can influence some parameters of HRV, implying a general and favorable effect of enhancing PNS over SNS influence on cardiac function during rest [22].…”

“…In fact, well-trained athletes are prime examples of individuals with a lower LF/HF ratio at rest [19][20][21] given the strong vagal effect on the heart. Even in sedentary and old subjects who take on intense exercise training, some HRV variable improvements track with improvements in cardiovascular fitness and health [22][23][24].…”