The Impact of Sex on Vascular Endothelial-Dependent Vasodilatory Adaptations to High-Intensity Interval Training in Older Adults

Blood vessel disease remains a leading cause of death in Canada. Advanced age and a decrease in the ability of cells inside the arteries to make them relax are both risk factors. Regular moderate-intensity exercise can improve blood vessel health in older adults but the benefits of this type of training are less in older women than men. Perhaps older women need a greater exercise stimulus? High-intensity interval training (HIIT) has been shown to be a safe and better form of exercise for blood vessel health in older adults. It may provide improved results in older women but we do not know if older men and women respond the same (or differently) to this form of training. The aim of this project is to find out if HIIT improves artery health more in older women versus men. We have already finished a small pilot study in 12 older adults (7 women) who completed HIIT. We will now recruit another 18 older adults (8 women) to complete HIIT. Artery health in the upper arm and lower leg will be measured using an ultrasound machine. Our test of artery health involves briefly slowing blood flow to the hand or foot using a pressure cuff. Once the cuff pressure is released, blood flow will increase and cause the artery to get bigger. The larger it gets, the healthier it is. These tests will be made before and after HIIT. We will also repeat these tests in a group of older men and women who do not engage in HIIT as a control measure. We are still unclear about the best type of exercise training for improving blood vessel health in older men and women. Moderate-intensity training does not appear to be as helpful in older women. As such, we need to study other training protocols. If we know whether HIIT programs enhance artery health differently in older men and women then we can start to develop better targeted strategies to prevent blood vessel disease in older adults.