Endurance training intensity has greater effects than volume on heart rate variability and arterial stiffness adaptations in sedentary adult men: A Randomized Controlled Trial.

Abstract

Background: The current study investigated the chronic effects of high-volume moderate-intensity training and low-volume high-intensity training on heart rate variability (HRV) and arterial stiffness in sedentary adult men. Materials and methods: Forty-five males (age: 42± 5.7 yrs.) were randomly assigned into control group (n=15), high-volume moderate-intensity training (HVMIT) (n=15), and low-volume high-intensity training (LVHIT) (n=15). The HVMIT group ran three times per week, on the treadmill at 50% to 60% of VO2max for 45 to 60 minutes, while the LVHIT trained at 70% to 85% of VO2max for 25 to 40 minutes. Both training programs were equated by caloric expenditure. HRV, Pulse Wave Velocity (PWV), hemodynamic variables, and body composition were measured before and after 12 weeks.Results: Both protocols (HVMIT and LVHIT) significantly increased the Standard deviation of NN intervals (SDNN) and High-frequency (HF) bands after 12 weeks (p ˂ 0.05). The LF/HF ratio decreased significantly in both training groups (p ˂ 0.05). However, these changes were significantly greater in the LVHIT protocol (p ˂ 0.05). Furthermore, the Root mean square of successive RR interval differences (RMSSD) significantly increased only in the LVHIT protocol (P ˂ 0.05). Moreover, a significant decrease in low-frequency (LF) and PWV was only observed following the LVHIT protocol (P ˂ 0.05). Conclusion: This study indicates that the LVHIT protocol is more effective and efficient for improving HRV variables and PWV than the HVMIT protocol.

Relationship between Cardiopulmonary, Mitochondrial and Autonomic Nervous System Function Improvement after an Individualised Activity Programme upon Chronic Fatigue Syndrome Patients

“…The HUTT might serve as a tool in the diagnosis of ANS dysfunction [9,10]. Whilst physical activity programmes might lead to improvement in the ANS in athletes [11], low-volume high-intensity training also improves HRV in sedentary adult men [12]. In addition, the relationship between increased VO2max and increased HRV has also been observed in response to a physical activity program [13].…”

“…Endurance training has the potential to increase mitochondrial functioning, improving biogenesis, mitophagy, and efficiency altering fusion and fission [27]. As already has been mentioned, physical activity programmes might lead to improvement of ANS in healthy participants [12,27]. Therefore, as disturbance in bioenergetics and ANS might be a presumably important parts of CFS pathogenesis, physical exercise program could be applied in patients to improve function of those systems.…”