Nitrate, exercise and vascular function in midlife women

The purpose of this clinical study in women after menopause is to investigate whether the daily intake of nitrate from beetroot juice over 12 weeks enhances the positive effect of exercise training on vascular function, blood pressure and physical performance. The background to the study is that the risk of cardiovascular diseases (CVD) increases with advancing age and women are particularly affected. In women, the decline in the sex hormone oestrogen in the blood circulation with menopause contributes to impaired vascular function and an increased CVD risk; in part through increased inflammatory processes, oxidative stress, and a reduced bodys own production of nitric oxide (NO). NO is a signaling molecule that is important for vascular function. Endurance-based exercise training is a key lifestyle strategy to prevent CVD. However, studies indicate that exercise is less effective in terms of its health-promoting adaptations in women after menopause as compared with men of similar age. Our study investigates the effect of exercise training in combination with the intake of nitrate- rich beetroot juice on the function and health of the cardiovascular system. Nitrate is a nitrogen compound that is found naturally in plant foods (e.g. beetroot juice) and is converted to NO in the human body. Results of previous studies by our and other research groups indicate vasodilatory, blood pressure-lowering and performance-enhancing effects as well as positive influences on inflammatory processes and oxidative stress following nitrate intake. The hypothesis is that nitrate intake concomitant to training promotes training adaptations and further improves vascular function, blood pressure and physical performance compared to training without nitrate intake. For the study, 54 untrained postmenopausal women (with the ages between 45 and 65 years) will be recruited and randomly allocated into two groups. Both groups will undergo 12 weeks of endurance-based exercise training. One group will receive nitrate-rich beetroot juice, and the other nitrate-depleted beetroot juice (as placebo). We will examine vascular function (using forearm blood flow measurements), blood pressure (including 24-hour blood pressure measurements), maximum oxygen uptake, and blood biomarkers for nitrate metabolism, inflammation status and oxidative stress. The anticipated results from this study will provide new insights into whether certain nutritional measures improve health-promoting training adaptations, especially in women after menopause. The overall aim is to improve the cardiovascular health and performance of middle-aged women and reduce their increased risk of CVD.