Many Tropicana readers will have heard of the performance benefits of beet juice. It has this effect for the same reason as your pre-workout 'NO-booster' – because it increases nitric oxide, which improves blood flow and oxygen delivery to muscles, along with numerous other proven and theoretical benefits.

Well, now the same has been shown for cocoa / dark chocolate. Previous studies have shown it to lower blood pressure (again by widening blood vessels and thus improving blood flow) but until recently, it hadn't been proven to increase exercise measures...but now it has! UK scientists from Kingston University. In the study, when subjects were given either dark chocolate (with cocoa) or white chocolate (without), the ones who got the real stuff had better oxygen delivery to muscles and better high-intensity exercise performance as measured by a very vigorous pedal for two minutes, all out on a spinning bike.

Some well-designed pre-workouts contain cocoa with standardised polyphenol content, which is believed to be the active ingredient, so look for these next time you are shopping for a pre-workout.

-Mark Gilbert BSc (Nutrition), CISSN