Runners, cyclists and other athletes increase their performance by eating 40 grams of dark chocolate every day for two weeks. Researchers at the University of Kingston in England discovered this when they conducted an experiment with several students. Adding a small piece of dark chocolate to their diet improved their endurance.
Study of the effect of 2 types of chocolate
The researchers gave 9 male students 40 g of chocolate over a two-week period twice. In one case, the chocolate was white, in the other ordinary – dark. This product contains relatively high amounts of epicatechin, the most important bioactive ingredient in cocoa, which promotes the release of nitric oxide (NO) through the activation of endothelial no synthase. Increased bioavailability of NO often shows a decrease in oxygen consumption and an improvement in performance during exercise of submaximal intensity.
Students ate chocolate instead of their usual dessert so that their daily energy intake remained constant. Before and after the two addition periods, the researchers tested the students on an ergometer. They asked the students to first do a 20-minute cycle at moderate intensity, and then, 30 minutes later, to sprint at maximum power for a few minutes. During each test, oxygen consumption, respiratory exchange rate (RER), heart rate, and blood lactate (BLa) were measured.
Results of the experiments conducted
Supplementation with dark chocolate increased the time that subjects could sprint during the load test.
BL = before you start taking chocolate; WC = white chocolate; DC = Dark Chocolate.
The researchers found no statistically significant effect of supplementation on maximum oxygen uptake, heart rate, lactic acid concentration in the blood or blood pressure. However, they found that giving students dark chocolate increased the gas exchange threshold [another term for this is the ventilation threshold, the anaerobic gas exchange threshold, the anaerobic ventilation threshold].
The threshold of gas exchange is the point where, during exercise, the body no longer receives enough oxygen through normal breathing. In other words: at a certain level of intensity, you begin to suffocate. Supplementation with dark chocolate seems to make the body more oxygen-efficient during moderately intense exercises and as athletes begin to choke to get enough oxygen at a higher intensity level. In healthy untrained individuals, the gas exchange threshold usually occurs at 40-60% of the maximum oxygen consumption level (VO2max) with a dispersion of normal values of 35-80%.
Mechanism of action of chocolate on the bioavailability of nitric oxide
Dietary supplements containing sodium nitrate or nitrate-rich beet juice are becoming increasingly popular and systematically show a decrease in oxygen requirements during submaximal exercise and rest. The physiological mechanisms underlying these improvements have been associated with nitrate degradation prior to a substantial increase in circulating nitrite, which is then converted to bioactive nitric oxide (NO), which can potentially increase vasodilation, glucose uptake, and regulate muscle contraction. Although the additive with beet juice has become popular as an ergogenic remedy, it is famous for its poor taste and energy quality. Recent studies have reported similar vascular improvements in NO levels of dark chocolate consumption. This is of great interest given the popularity of this product among the population. Dark chocolate is mechanically unique to other nitrate dietary supplements which increases NO production by endothelium-dependent effects. The abundant amounts of epicatechin present in dark chocolate release vasoactive components from endothelial cells, thereby increasing the bioavailability of NO.
Imprisonment
“It can be concluded that taking dark chocolate for 14 days reduces oxygen consumption in moderate intensity exercises and can be an effective ergogenic treatment for short-term exercises of moderate intensity,” the researchers write.
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