The performance enhancing effect of Red Bull, probably the most popular energy drink in the world, is partly due to the fact that Red Bull suppresses pain sensation. Health scientists at the American Winona State University drew this conclusion from a series of experiments they carried out with seventy students. Their research, which has been published in Amino Acids, showed up no negative effects on the cardiovascular system.
Some years ago the directors of the Austrian Red Bull concern were sleeping badly. This was due to the Australian cardiologist Scott Willoughby, of the Cardiovascular Research Centre at the Royal Adelaide Hospital. Willoughby’s students had come up with the idea of researching whether Red Bull was dangerous to the heart. The students themselves drank Red Bull in quantities, and students also read newspapers. They had noticed that there were regular reports in the press in recent years of people who had developed medical problems as a result of drinking Red Bull.
In Darlington, England a 15-year-old was admitted to hospital in 2008 with heart palpitations after drinking eight cans of Red Bull. In the same year a man in Oxford died at his work, also after drinking large quantities of Red Bull.
Willoughby’s research received media attention before it was even published. [The Australian August 15, 2008] [The Times August 15, 2008] He had discovered that Red Bull Light makes the blood thicker, probably because the platelets start to stick to each other more. Added to that, the blood vessels become slightly less elastic, and as a result the body starts to have more difficulty in pumping the blood. In fact all the changes remained within the safety margins, but Willoughby regarded them as serious enough to warn users. “If you have any predisposition to cardiovascular disease, I’d think twice about drinking it”, said the researcher in an interview.
The Red Bull company contacted the researchers and Willoughby sent his material to Austria. But the story doesn’t stop here. Even before Willoughby’s study was published another study appeared, from Winona State University, which contradicts Willoughby’s findings. It’s not clear from the article whether Red Bull financed this study. In fact there is no reference in the article at all to any sponsor.
The researchers gave their test subjects a zero-joule placebo [LCP], a can of Red Bull Light [LCRB], a placebo containing sugars [NCP] or a can of Red Bull with glucose [NCRB]. They then monitored the electrical pulses in the hart, taking note in particular of the QT-interval. If this increases it may indicate an early stage of heart disease. The figure below shows however that Red Bull has a negligible effect on the QT-interval.
The researchers also measured blood pressureduring the heart muscle contractions [systolic blood pressure] and between two heart beats [diastolic blood pressure]. In fact Red Bull lowered blood pressure.
This is not totally unlikely. 100 ml of Red Bull contains 32 mg caffeine, which is a stimulant and raises blood pressure, but also 400 mg of taurine. In theory taurine makes the cells absorb more adrenalin and noradrenalin. As a result muscle cells work harder and the hormones disappear from the blood. This in turn reduces blood pressure, as adrenalin and noradrenalin both have a narrowing effect on the arteries. If you drink a can of Red Bull apparently the positive effect of the taurine outweighs the negative effect of the caffeine. At least as far as blood pressure is concerned.
The researchers also got the students to put their hand in a bowl of ice-cold water. The students had to say when it was causing them pain. In this way the researchers measured the pain threshold, shown in the table below. When the students could bear it no longer they were allowed to take their hand out of the water, thus giving the researchers an indication of their pain tolerance. The table below shows how the students’ pain sensation was suppressed by drinking a can of Red Bull.
Amino Acids. 2009 Aug 4. [Epub ahead of print].