Energy drinks claim to boost your energy and improve performance but they are different from sport drinks such as Gatorade or PowerAde, which have small amounts of carbohydrate and electrolytes.

Here's a look at what energy drinks contain.

Caffeine. Energy drinks have caffeine listed as Guarana, yerba mate or caffeine. They usually have about 80 mg in a 250 ml can, double the amount found in pop and about half the amount found in coffee.

Taurine. Most energy drinks contain one gram of taurine, an amino acid that is easily obtained in the diet from meat and dairy products. Although the claim is that taurine increases alertness, there is no research to support it.

Herbs. Ginkgo biloba and ginseng are listed ingredients in many energy drinks. These can interfere with medications affecting blood clotting. There is no research to support that these herbs improve sports performance.

Sugar. These beverages contain about twice the amount of sugar (carbohydrate) as a sport drink and so will interfere with performance. If drank just before or during exercise they may cause nausea, cramps and diarrhea. High doses of sugar may have a short term energy burst, but the body will quickly get the sugar out of the blood stream, causing a big drop in blood sugar about 70 to 80 minutes later. According to research this may slow reaction time both physically and mentally.

Health Canada regulates energy drinks as supplements. It recommends not consuming more than 500 ml per day and cautions not to mix with alcohol.

For anyone in vigorous exercise situations, sport drinks or water are the best choices during exercise. A 20-minute nap, regular meals and snacks throughout the day or a quick power walk are natural ways to boost your energy and alertness.

Diane Britton is the University of Lethbridge's On-campus Registered Dietitian