Acute effects of low-volume intermittent versus higher-volume continuous exercise on arterial stiffness in healthy young men

Figure 1. Study protocols for exercise, rest interval, recovery and measurements in five trials: non-exercise control trial (CON), high-volume continuous exercise trial (CE, one 30-min bout), low-volume intermittent exercise of long bouts with long interval (ILL, two 10-min bouts separated by 20-min interval), intermittent exercise of long bouts with short interval (ILS, two 10-min bouts separated by 5-min interval), and intermittent exercise of short bouts with short interval (ISS, four 5-min bouts separated by 5-min intervals). Time points of measurements were baseline (BL), immediately (0 min), and 40 min after exercise in CE, ILL, ILS and ISS trials.

Figure 2. Time course of arterial stiffness response to exercise with and without interval of different duration. Mean (± SD) time-dependent ⊿CAVI changes in CON, CE and ILL trials (a) and CON, CE and ILS trials (b). Statistical analysis was performed using two-factor (treatment and time) repeated measures ANOVA with Bonferroni post-tests. Data are means ± SD, n = 20. *P < 0.0001, CE, ILL, ILS and ISS vs. CON at 0 min. #P < 0.05, ILS vs. CON and CE at 40 min. CAVI Cardio-ankle vascular index, BL baseline, CON control, CE continuous exercise, ILL intermittent exercise of long bouts with long interval, ILS intermittent exercise of long bouts with short interval, ISS intermittent exercise of short bouts with short interval.

Figure 3. Time course of arterial stiffness response to exercise of different bouts with short interval. Mean (± SD) time-dependent ⊿CAVI changes in CON, CE, ISS trials (a), and CON, ILS and ISS trials (b). Statistical analysis was performed using two-factor (treatment and time) repeated measures ANOVA with Bonferroni post-tests. Data are means ± SD, n = 20. *P < 0.0001, CE, ILS and ISS vs. CON at 0 min. &P < 0.05, ISS vs. CON at 40 min. $P < 0.01, ISS vs. CE at 40 min. †P < 0.01, ISS vs. CON at 40 min.CAVI Cardio-ankle vascular index, BL baseline, CON control, CE continuous exercise, ILL intermittent exercise of long bouts with long interval, ILS intermittent exercise of long bouts with short interval, ISS intermittent exercise of short bouts with short interval.

Figure 4. Mean (± SD) time-dependent ⊿CAVI changes undergoing ISS trial. CAVI was measured at baseline, immediately before the second (B1), third (B2) and fourth bout (B3) respectively, and immediately after exercise (0 min), and 40 min after exercise (Fig. 1). Statistical analysis was performed using one-way ANOVA with repeated measures with Bonferroni post-tests. Data are means ± SD, n = 13. *P < 0.05 vs. BL; **P < 0.01 vs. BL; ***P < 0.001 vs. BL. CAVI Cardio-ankle vascular index, BL baseline.