Research from Exeter University shows how drinking beetroot juice can make exercise easier by boosting stamina. Published May 13, in the Journal of Applied Physiology, the study reveals how drinking beetroot juice reduces the energy expended by muscles.
The research builds on a previous study (published in the Journal of Applied Physiology), which showed for the first time that drinking beetroot juice can boost stamina, allowing an individual to exercise for up to 16 per cent longer. The authors suspected that this was connected to the very high nitrate content of beetroot juice turning into nitric oxide in the body, leading to a reduction in oxygen uptake. This latest study confirms that initial finding and also reveals the processes in the muscles that make exercise less tiring.
For the study, seven healthy men completed a series of knee extension exercises, which work the quadriceps muscles in the thigh. The level of exertion was assessed using a custom-designed ergometer. An MRI scanner enabled the researchers to record the internal processes of the muscle. In addition, the volunteers’ oxygen uptake was monitored. The exercises were repeated several times, sometimes after the volunteers had drunk half a litre of organic beetroot juice a day over six days and sometimes after they had drunk a placebo of blackcurrant cordial.
Drinking beetroot juice doubled the amount of nitrate in the blood of the volunteers and reduced the rate of utilization of adenosine triphosphate (ATP), the most immediate source of energy for muscles. This suggests that drinking beetroot juice enables muscles to complete the same work more efficiently. Furthermore, after drinking beetroot juice, oxygen uptake was reduced during both low-intensity and high-intensity exercise.
Corresponding author of the study, Professor Andy Jones of the University of Exeter’s School of Sport and Health Sciences, said: “We continue to be impressed by the physiological effects of increasing dietary nitrate consumption. While our previous research demonstrated the benefits of nitrate-rich beetroot juice on stamina, our latest work indicates that this is consequent to a reduced energy cost of muscle force production.
“Since our first study came out we have seen growing interest in the benefits of drinking beetroot juice in the world of professional sport and I expect this study to attract even more attention from athletes.”