There are a plethora of "performance enhancing"drinks and supplements on the market that work on a variety of biological functions. Some are just straight caffeine, others attempt to increase levels of certain hormones, still more pump you full of carbohydrates or proteins and a relatively new group to the mix utilize nitrates to boost muscle endurance.
The specific nitrate at work here is converted to one helpful fellow called nitric oxide, not to be confused with nitrous oxide which is laughing gas. Nitric oxide is a gas that acts in the body as a neurotransmitter, meaning that it carries messages from the brain. In it's messaging work, however NO is directly responsible for controlling the flow of blood and oxygen to certain parts of that body when they need it most.
But there's something special about how NO does it. Think of it this way: You have a narrow tube and you're trying to blow water through it. Give enough time you can move a large amount of water but to increase the flow you have to increase the amount of pressure you put behind it. You'd have to really puff up your cheeks and struggle a bit. Or you could just use a wider tube.
NO opens and relaxes the blood vessels which allows more blood to travel through them while also lowering blood pressure. Nitric oxide supplements have been very popular amongst body builders for years.
So... what's this got to do with beet juice?
Well in addition to the effects of NO, beets have an as-of-yet unexplained ability to reduce the oxygen needs of your muscles.
Since 2009 a host of studies have been released showing exactly how much it can help people, specifically those involved in endurance training. The first of these studies was led by the University of Exeter in the U.K and found that an intake of 500ml (about 16 fluid ounces) increased the subjects' ability to endure exercise substantially. Those that took beetroot juice lasted 92 seconds longer on a bike than the control group for a 16% increase.
Another study showed that these benefits also work for low-intensity activities, like walking. This means that beets have a potential for helping those who struggle with daily activities but more research is still needed.
The most recent study tested these effects directly on endurance athletes and also isolated the active ingredient. The subjects, club-level competitive cyclists were asked to complete time trials at 2.5 and 10 miles. They biked each race twice, once with normal beet juice and again with a juice that had had the nitrates removed. Here are the results: "On average, riders [who had taken normal beet juice] were 11 seconds (2.8%) quicker over the 4km distance and 45 seconds (2.7%) faster over the 16.1km distance."
In all of these studies, the magic number was 500ml (or 16 ounces) of beet juice.
It should be noted that anyone with kidney problems or hypocalcemia (low calcium) should talk it over with their doctor before getting crazy with the beet juice. Also, a harmless but somewhat unnerving side effect of beet consumption is red or pink urine. So don't panic if that happens.
While the function of the nitrates in beet juice do not rival the muscle-increasing effects of some other commercially available NO supplements, the pulpy red juice will like be enough to give everyone from endurance athletes to slightly active people an edge.