Previously, studies have shown that beetroot juice can improve blood pressure and tolerance to exercise. Katherine E. Lansley, from the Peninsula College of Medicine and Dentistry (United Kingdom), and colleagues assessed the physiological effects of drinking beetroot juice among healthy adults. Noting that beetroot juice contains high levels of nitrate, a substance that widens blood vessels, reduces blood pressure, and allows more blood flow, the researchers report that beetroot juice reduces the amount of oxygen needed to perform low intensity exercise. The team studied nine healthy, physically active male adults for a six day period during which each subject received beetroot juice and conducted standardized exercises. Beetroot juice elevated plasma nitrite and reduced systolic blood pressure. As well, beetroot juice reduced the oxygen cost of walking, moderate intensity running, and severe intensity running. The team concludes that: "These results indicate that the positive effects of six days of [beet root juice] supplementation on the physiological responses to exercise can be ascribed to the high nitrate content."