As you may be aware beets are a great source of nitrates. This is then converted to nitric oxide which is a vasodilator.
Nitric Oxide cases a decrease in the resistance of peripheral blood vessels and can result in reduced blood pressure.
This study the athletes received 140 milliliters of beet juice every day. While the athletes didn’t show any difference in blood pressure they did find times in 5K runs were 18 seconds quicker for the control group as opposed to the placebo group.