Document Type : Research Paper

Authors

• ahmad fasihi ¹
• Yaser Roozbahani ²

¹ exercise physiology- human science- university of Malayer- Malayer- Iran

² 2. Department of Physical Education, Faculty of Humanities, Islamic Azad University, Hamedan Branch, Hamedan, Iran

Abstract

Purpose: Heart rate variability (HRV) is a marker of cardiac autonomic regulation, with reduced HRV linked to increased cardiovascular risk. While aerobic exercise improves HRV, data on healthy women remain limited. This study aimed to assess the impact of 12 weeks of endurance training on resting HRV indices in healthy female volunteers. Method: In a pre-test–post-test controlled design, healthy women were randomly assigned to an endurance training group or a control group. The training group performed moderate-intensity continuous exercise three times per week for 12 weeks. HRV was measured before and after the intervention using short-term ECG recordings, analyzing time-domain indices (SDNN, RMSSD) and high-frequency (HF) components, along with the LF/HF ratio. Statistical significance was set at p<0.05. Results: After 12 weeks, the training group showed significant improvements in SDNN (from 45±5 to 58±7 ms, p=0.023), RMSSD (from 25±3 to 36±5 ms, p=0.033), and HF (from 210±30 to 310±45 ms², p=0.033), while the control group showed no significant changes. Between-group comparisons confirmed significantly higher post-intervention SDNN, RMSSD, and HF in the training group (p=0.02). The LF/HF ratio did not change significantly in either group. Conclusion: Twelve weeks of endurance training significantly improved HRV indices (SDNN, RMSSD, HF) in healthy female volunteers, suggesting enhanced autonomic regulation. These results support incorporating endurance exercise in lifestyle recommendations for women to improve cardiac health.

Keywords

• Heart rate variability
• endurance training
• female
• sympathetic nervous system
• parasympathetic nervous system

Main Subjects

• Exercise Physiology