Effects of high-intensity interval training on vascular function and maximum oxygen uptake in young sedentary females

Objective: Sedentary behavior is one of the risk factors for cardiometabolic diseases, including cardiovascular diseases, diabetes mellitus, and metabolic syndrome. High-intensity interval training (HIIT) is one effective way to reduce the risk of cardiometabolic diseases. This research studies the effects of cycling-based HIIT on vascular function and cardiorespiratory fitness in sedentary people. Methods: Twenty-two female participants were separated into two groups, including HIIT group who receive intervention and control group who did not receive the intervention. Each of the participants was interviewed to collect and record their medical history, and medical parameters including cardio-ankle vascular index (CAVI), flow-mediated dilation (FMD), and maximal oxygen consumption ((V) over dotO(2max)) were measured as a baseline pre-test. The intervention was a cycling-based HIIT lasting 6 weeks, with three sessions per week. During each session, the participant completed a set protocol consisting of 1 min on a cycle ergometer, cycling at 80-85% maximal heart rate, followed by a 1-min rest period. This sequence was repeated for a total of 5 times. Results: After 6 weeks of intervention, results showed that the HIIT group had significant improvements in CAVI (6.39 +/- 0.76 vs. 5.91 +/- 0.58), FMD (9.26 +/- 6.5 vs. 14.01 +/- 4.3%), and (V) over dotO(2max) (20.10 +/- 4.31 vs. 24.34 +/- 5.71 ml/kg/min) values compared to the pre-test (P < 0.05). In addition, HIIT increased endothelial function as measured by FMD compared to the control group (14.01 +/- 4.3 vs. 9.15 +/- 4.16 %, P < 0.05). Conclusion: Six weeks of HIIT were found to improve vascular function and cardiorespiratory fitness in sedentary people and demonstrated the benefits of HIIT as a time-efficient exercise strategy.