The Effects of High-Intensity Interval Training on Arterial Stiffness in Elderly People with Increased Cardiovascular Risk

Background: Arterial stiffness (AST) is an independent predictor of cardiovascular risk (CVR) and all-cause mortality. Exercise interventions are considered to reduce AST; however, data on elderly individuals with increased CVR is scarce. This study aimed to examine whether 12
weeks of high-intensity interval training (HIIT) yielded a decrease in central pulse wave velocity (cPWV) in a sedentary middle-aged and older population with increased CVR. Secondary outcomes were peripheral pulse wave velocity (pPWV) and normalized augmentation index (AIx@75).
Methods: A total of 68 participants (mean age 58 ± 6) were randomized into control (CON: n= 30) or intervention group (INT: n = 38). INT underwent a 4x4-HIIT 3 times a week for 12 weeks. Carotid-femoral and femoral-tibial pulse wave velocity, as well as AIx@75 were assessed using applanation tonometry (SphygmoCor®). ANCOVA was used for group comparison at follow-up.
Results: At follow-up, INT showed no significant changes in cPWV (pre: 8.2 ± 1.2 m/s, post: 8.1 ± 1.1 m/s; p = 0.29), pPWV (pre: 8.7 ± 1.0 m/s, post: 9.1 ± 1.3 m/s; p = 0.94) and AIx@75 (pre: 22 ± 9%, post: 21 ± 10%; p = 0.51). Higher cPWV baseline values were correlated with a more profound cPWV decline (p = 0.001). A significant association between the reduction in cPWV and decreases in systolic blood pressure (SBP) was found (p = 0.01). Peak Oxygen uptake (VO2PEAK), muscle mass and fat mass had significantly improved at follow-up.
Conclusion: A HIIT of 12 weeks did not lead to significant reductions in AST. However, in patients showing increased SBP and high cPWV baseline values, HIIT yielded a greater decline in cPWV and thus reduced CVR. To favourably alter AST in sedentary elderly individuals with increased CVR, longer interventions (> 12 weeks) are needed.