Chronic Effects of Different Intensities of Interval Training on Hemodynamic, Autonomic and Cardiorespiratory Variables of Physically Active Elderly People

Abstract

Background Interval training is an important strategy for promoting physiological adaptations. Therefore, this study aimed to verify the chronic effects of interval training (TI) with different intensities on hemodynamic, autonomic and cardiorespiratory variables of physically active elderly people. Methods Twenty-four physically active older men (age: 68.8 ± 6.8 years, body mass: 74.4 ± 18.1 kg, height: 170 ± 8 m, body mass index: 25.1 ± 2.2 kg / m²) participated in the study. Participants were randomized into three experimental groups: training group A (TGA, n = 8), training group B (TGB, n = 8), and control group (GC, n = 8). TGA and TGB groups performed 32 training sessions separated by a 48-hour interval. TGA showed 4-min with intensity relative to 55 to 60% of the HRmax and 1-min at 70 to 75% of the HRmax. TGB training group performed the same protocol but performed 4-min at 45 to 50% HRmax and 1-min at 60 to 65% HRmax. Both training groups performed each series for six times, totaling 30-min per session. The evaluations were carried out in the pre (baseline) moments after the 16th and 32nd intervention sessions. GC only carried out assessments. Hemodynamic variables (HRR, SBP, DBP, MBP, and DP), autonomic (HRV indices, in the time and frequency domain), and cardiorespiratory (VO2max estimated) variables were evaluated. Results There were no statistically significant differences in comparisons between protocols and moments (p > 0.05). However, the size of the effect and the percentage delta indicated clinical results with relevant magnitudes between protocols and moments, indicating favorable responses to the IT intervention in hemodynamic, autonomic, and cardiorespiratory variables. Conclusion IT can be an essential strategy in the prescription of training for conditional improvement of variables of cardioprotective function in physically active and healthy older people. However, other studies are suggested to establish the efficiency of this method for cardiovascular and cardiorespiratory variables in the elderly.