Effect of exercise training on heart rate variability in type 2 diabetes mellitus patients: A systematic review and meta-analysis

Abstract

Background Cardiac autonomic neuropathy is a common complication of type 2 diabetes mellitus (T2DM), that can be measured through heart rate variability (HRV)–known to be decreased in T2DM. Physical exercise can improve HRV in healthy population, however results are under debate in T2DM. We conducted a systemic review and meta-analysis to assess the effects of physical exercise on HRV in T2DM patients. Method PubMed, Cochrane, Embase, and ScienceDirect databases were searched for all studies reporting HRV parameters in T2DM patients before and after exercise training, until September 20th 2020, without limitation to specific years. We conducted random-effects meta-analysis stratified by type of exercise for each of the HRV parameters: RR–intervals (or Normal to Normal intervals–NN), standard deviation of RR intervals (SDNN), percentage of adjacent NN intervals varying by more than 50 milliseconds (pNN50), root mean square of successive RR-intervals differences (RMSSD), total power, Low Frequency (LF), High Frequency (HF) and LF/HF ratio. Sensitivity analyses were computed on studies with the highest quality. Results We included 21 studies (9 were randomized) for a total of 523 T2DM patients: 472 had an exercise training and 151 were controls (no exercise). Intervention was endurance (14 studies), resistance (2 studies), endurance combined with resistance (4 studies), and high intensity interval training (HIIT) (4 studies). After exercise training, all HRV parameters improved i.e. an increase in SDNN (effect size = 0.59, 95%CI 0.26 to 0.93), RMSSD (0.62, 0.28 to 0.95), pNN50 (0.62, 0.23 to 1.00), HF (0.58, -0.16 to 0.99), and a decrease in LF (-0.37, -0.69 to -0.05) and LF/HF (-0.52, -0.79 to -0.24). There were no changes in controls. Stratification by type of exercise showed an improvement in most HRV parameters (SDNN, RMSSD, pNN50, LF, HF, LF/HF) after endurance training, whereas mostly LF/HF was improved after both resistance training and HIIT. Supervised training improved most HRV parameters. Duration and frequency of training did not influence the benefits on HRV. Conclusion Exercise training improved HRV parameters in T2DM patients which may reflect an improvement in the activity of the autonomic nervous system. The level of proof is the highest for endurance training. Supervised training seemed beneficial.

Heart Rate Variability and Cardiovascular Fitness: What We Know so Far

“…Several studies have indicated a positive relationship between controlled metabolic parameters, cardiovascular fitness, and autonomic modulation of HRV. [103][104][105][106] Among these effects, the improvement in glucose metabolism associated with an increase in insulin sensitivity stands out. Other important effects have also been observed, such as reduction in fat mass, improvement in body composition, and reduction in inflammatory and oxidative stress markers.…”

“…104,105,[107][108][109][110] Consequently, all these beneficial effects resulting from the increase in cardiovascular fitness can contribute to the improvement on autonomic modulation of HRV. That is, increased cardiovascular fitness results in a better balance of cardiac autonomic modulation, characterized by increased vagal modulation and/or reduced sympathetic modulation, 106,109,111 which has been observed in patients with major complications and comorbidities due to diabetes. 112,113 Furthermore, all these benefits of better cardiovascular fitness, in addition to contributing to the regulation of the autonomic modulation of HRV, also contribute to the prevention of cardiovascular diseases and improvement in quality of life in general.…”

Acoustic Photometry of Biomedical Parameters for Association with Diabetes and Covid-19

“…Heart rate in any state of rest, deep breathing, recovery, and lying to standing are highest in known diabetic conditions. Resting heart rate can be a crucial factor in the early detection of COVID-19, whereas extreme elevation of an individual's resting heart rate can be an early sign that he or she is infected with COVID-19, or simply requires medical attention [28]. The results in this study were compared to those reported in [13] and for commercialised pulse oximeters, showing a more or less similar accuracy of 97%.…”

Effect of Physical Activity on Cardiovascular Event Risk in a Population-Based Cohort of Patients with Type 2 Diabetes

“…In fact, some CVD risk models derived for the general population have been shown to be suboptimal when applied to patients with T2D [ 5 , 6 ]. In patients with type 2 diabetes (T2D), different exercise modalities, such as walking, aerobic, resistance, strength, yoga or certain combinations, have been found to improve the levels of the most important CVD risk factors, including hemoglobin A1c (HbA1c), glucose, low-density lipoprotein (LDL), total cholesterol, heart rate and weight [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. Most of the evidence relating to PA and CVD risk is based on short-term interventional randomized clinical trials and focused on these intermediate outcomes.…”