The effects of acute moderate versus high intensity interval exercise on arterial stiffness

Introduction: Aerobic exercise is known to favourably alter arterial stiffness and wave reflection. However, the effect of different types of aerobic exercise on arterial wave reflection has yet been poorly explored. The purpose of this study was to investigate the acute effects of a high-intensity interval exercise (HIIT) and a moderate continuous exercise (MCT) on augmentation index (AIx), a parameter characterising arterial wave reflection. Method: 21 healthy young men (age 24.3 ± 2.5 years) completed in random order a HIIT and a MCT. At baseline and 5, 20, 35 and 50 min post-exercise hemodynamic and arterial parameters were captured using applanation tonometry from radial artery (SphygmoCor® device). Results: AIx corrected for heart rate (AIx@75) was significantly increased immediately after HIIT (–11.2 ± 2.2% vs. 9.5 ± 1.4% [pre vs. 5 min post], mean ± SE, p < 0.001) and this increase remained significant until 35 min after exercise termination. Following MCT, AIx@75 was only increased at 5 min post-exercise (–11.8 ± 1.6% vs. –4 ± 1.8% [pre vs. 5 min post], mean ± SE, p = 0.013). AIx@75 was significantly higher following HIIT than after MCT (p < 0.001, main effect for mode). Conclusion: Following HIIT a more pronounced increase in pulse wave reflection was observed and these effects persisted for a longer time period in the recovery phase compared to MCT. This increased wave reflection indicates increased central arterial stiffness after acute HIIT, which may be associated with the long term effect of reducing arterial stiffness after chronic HIIT.