In fact, the results showed up to a 20% increase in exercise duration and a 1 to 2% improvement in race times. The study is published online in the Journal of Applied Physiology.
This new research is supported by earlier Exeter research that showed that beetroot juice, with a high content of nitrate, also increases nitric oxide in the body and improves endurance and performance. The current study focuses on the use of a dietary supplement to achieve these effects. Healthy male athletes were subjected to a series of physical challenges on an exercise cycle. Half the volunteers were randomly assigned to take Ark 1, a supplement containing L-arginine, the amino acid that enhances production of nitric oxide in the body. The other half took a blackcurrant cordial placebo drink. The participants' performance at different levels of exercise intensity was measured. Those who took the supplement had up to 20% improved exercise endurance under intense conditions, significantly reduced systolic blood pressure, and a reduction in the oxygen cost of exercise.
Andrew Jones, professor of the University of Exeter's School of Sport and Health Sciences says, "The research found that when the dietary supplement was used there was a striking increase in performance by altering the use of oxygen during exercise. This is important for endurance athletes as we would expect this supplement to bring a 1-2% improvement in race times. While this may seem small, this is a very meaningful improvement, particularly at elite levels where small gains can be the difference between winning and losing."