Beet juice may hold some benefits for athletes that down it before exercising, by "de-stiffening" blood vessels under resting conditions, potentially easing the workload of the heart, a new study says.
Endurance athletes have long consumed the crimson drink believing that it may improve blood and oxygen flow in their muscles during training and competition. Meanwhile, some strength and power athletes drink beet juice hoping that it will improve their ability to withstand muscle fatigue during repeated bouts of high intensity exercise.
However, despite the myths, this new study, published the journal Applied Physiology, Nutrition, and Metabolism, found that beet juice rich in nitrates did not enhance muscle blood flow or vascular dilation during exercise.
Nitrates are found in the highest concentrations in leafy green vegetables such as spinach and beetroot, and are converted naturally in the body to nitric oxide. This molecule relaxes and widens blood vessels and affects how efficiently cells use oxygen. During the study, researchers either gave participants a placebo drink containing beetroot juice minus the nitrate, or a relatively high dose of nitrate-rich beetroot juice.
"Although several studies have reported indirect evidence of improved muscle oxygenation during exercise after consuming nitrate-rich supplements such as beetroot juice, none of these studies directly measured blood flow to the contracting muscles," David Proctor, a professor of kinesiology and physiology at Penn State, said in a statement. "Our study was the first to directly test this possibility in humans."
The results showed a direct correlation between nitrite levels in the blood and the slowing of participants' arterial pulsation velocity, which indicates an artery "de-stiffening" effect.
"It is possible that any blood flow enhancing effect of dietary nitrate will only be apparent during higher intensity and fatiguing work intensities; conditions within the muscle that favor the conversion of nitrite to nitric oxide," Proctor noted.
However, more research is need to say for sure if beet juice has any added benefits for athletes.
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