Author(s): CHEN, L.Y., WANG, C.W., CHEN, L.A., HE, C.S., Institution: NATIONAL CHUNG CHENG UNIVERSITY, Country: TAIWAN, Abstract-ID: 640

INTRODUCTION:
Cardiovascular disease (CVD) stands as a primary contributor to global mortality. Arterial stiffness has been established as an independent risk factor for both CVD and mortality. Peripheral pulse wave velocity (pPWV) serves as an indicator of arterial stiffness and represents a significant risk factor for CVD. Previous research has demonstrated an association between vitamin D deficiency and arterial stiffness (1). Prior study has indicated that high intensity interval training (HIIT) can effectively improve arterial stiffness (2). However, the impact of HIIT training on individuals with different levels of vitamin D remains unclear. The primary objective of this study was to compare different vitamin D status on vascular function following two weeks HIIT in healthy adults.
METHODS:
Forty-three adult males were divided into the 25(OH)D sufficient group (n=29, vitamin D≧50 nmol/L) and deficient group (n=14, vitamin D <50 nmol/L). The maximal graded exercise was performed using on upright bikes an incremental cycling test to exhaustion. The training intervention consisted of two weeks of high intensity cycling training, five days/week, consisting of 10 × 1 min bouts at 90% of HRpeak with 1 min rests. The pPWV and blood pressure (BP) were measured at baseline, on the mid-training, and post-training. The pPWV and BP variables were subjected to a two-way analysis of variance (ANOVA). Subsequent to identifying significant interaction and main effects, post hoc comparisons were conducted using t-test analysis. Changes in mean arterial pressure (MAP) and pPWV during HIIT were assessed using the area under the curve (AUC) method based on the trapezoidal rule, followed by a t-test on AUC values between groups. The accepted level of significance was set at p < 0.05.
RESULTS:
Baseline characteristics showed no significant differences, except for vitamin D concentrations. Both the vitamin D sufficient and deficient groups exhibited a significant reduction in pPWV (p < 0.05). The vitamin D sufficient group showed a significant lower systolic BP at post-HIIT compared with deficient group (116.17 ± 11.39 vs 120.25 ± 11.22 mmHg). The sufficient group demonstrated a significant reduction in systolic BP at post-HIIT compared to baseline (122.59 ± 13.65 vs 116.17 ± 11.39 mmHg). In addition, AUC for both pPWV and MAP in vitamin D sufficient group was significantly smaller than deficient group (p < 0.05). There were no significant changes in systolic BP between the baseline and post-HIIT training in the vitamin D deficient group (p > 0.05).
CONCLUSION:
In this study, we found that adults with 25(OH)D sufficiency have a better vascular function improvement after two weeks of HIIT. People with sufficient vitamin D status may experience better vascular vasodilation and blood pressure reduction during each high-intensity training session.

1. Chen, L. Y., et al. Nutrients, 14(15), 3074. (2022)
2. Hasegawa, N., et al. Med Sci Sports Exerc 50(6), 1177-1185. (2018)