Flowers are a wonderful Valentine’s Day gift, and while they usually last a few days longer than chocolate, they don’t taste quite as good. They also don’t do much for athletic performance, if that kind of thing is on the menu, and chocolate apparently does help out. Researchers at Kingston University, who were aware that beet juice is rich in nitrates, which are converted to nitric oxide in the body, suspected that dark chocolate, whose flavanols also increase nitric oxide production in the body, might provide a similar boost. They divided a group of 23 amateur cyclists into two, and asked one group to replace one of its normal daily snacks with 40g of a dark chocolate known to be rich in flavanols for a fortnight, while cyclists in the other group substituted 40g of white chocolate for one of their daily snacks as a control. A Kingtson U news release reports that the effects of the athletes’ daily chocolate consumption were then measured in a series of cycling exercise tests, and the cyclists’ heart rates and oxygen consumption levels were measured during moderate exercise and in time trials. After a seven-day interval, the groups switched chocolate types and the two-week trial and subsequent exercise tests were repeated. The researchers found that after eating dark chocolate, the riders used less oxygen when cycling at a moderate pace and also covered more distance in a two-minute flat-out time trial.