The effects of aerobic and resistance training on HRV parameters in individuals with type 2 diabetes mellitus

Abstract

Background: Heart rate variability (HRV) is a non-invasive marker of autonomic nervous system (ANS) function and cardiovascular health, reflecting beat-to-beat fluctuations in heart rate. Exercise training is recognized as a potential modulator of HRV, particularly in individuals with type 2 diabetes mellitus (T2DM), a condition often associated with impaired autonomic function.

Objective: This study aimed to compare the effects of aerobic and resistance training on HRV parameters in individuals with T2DM over a 12-week period.

Methods: A total of 100 participants with T2DM were randomized into either an exercise group or a control group. Baseline and post-intervention assessments included anthropometric parameters (height, weight, BMI, waist circumference, body fat percentage), hemodynamic measures (blood pressure, resting heart rate), and HRV indices. Physical fitness outcomes, including handgrip strength, leg strength, maximal oxygen uptake (VO₂max), and muscle endurance, were also evaluated. The exercise group underwent a supervised 12-week program comprising combined aerobic and resistance training, performed three times weekly.

Results: Compared with controls, participants in the exercise group demonstrated significant reductions in body weight, waist circumference, body fat percentage, and both systolic and diastolic blood pressure (p < 0.05). Improvements were also observed in VO₂max, handgrip strength, and bilateral leg strength. However, no statistically significant changes in HRV indices were detected between groups after 12 weeks.

Conclusion: While combined aerobic and resistance training improved cardiovascular risk factors, muscle strength, and cardiorespiratory fitness in individuals with T2DM, it did not significantly alter HRV parameters within the study period. Larger and longer-term studies are warranted to further clarify the impact of structured exercise on autonomic regulation in this population and to explore the role of individualized training regimens for optimizing health outcomes.