You’re getting ready to head to the gym, go out for a jog or bike ride, or play tennis with some friends. You grab your shoes, workout gear, a towel and a sports drink.
The History of Sports Drinks
Created in a lab in 1965 at the University of Florida, Gatorade is considered the world’s first sports drink. It was the result of a plea from a Gators’ football coach to university scientists to come up with a way to help his players perform in the heat. Thus Gator-ade was born. The following year, the Gators won the Orange Bowl the following year. And in 1969, the Kansas City Chiefs used Gatorade and won the Super Bowl.
Today, the global sports drink industry is worth $24 billion per year. And it’s expected to increase by more than a third by 2027. The biggest consumers are teens, with more than half reporting having a sports drink in the past week. This is followed by young adults, with about one-third reporting having a sports drink at least once per week.
Marketed by professional athletes, sports drinks are a mix of water, sugar (glucose, sucrose and/or fructose) and electrolytes (such as sodium and potassium). Vitamins, flavouring and colouring may also be added. They’re designed to improve athletic performance. They also differ from energy drinks, which contain caffeine and other stimulants.
Main Energy Sources During Exercise
In order to understand why sports drinks might help exercise, one needs to understand what happens during exercise. There are two main sources of energy during exercise, fat and glucose. Glucose is also referred to as sugar or carbohydrate. What energy source, and how much, depends on the duration and intensity of exercise. And to some extent your fitness level. Most people exercise at a light to moderate level. At this level, energy comes from a mix of fat and glucose.
Fat is the energy powerhouse providing more than twice the amount of calories per gram than glucose (9 vs. 4 calories). And since the average person’s weight is 20%-40% fat, our fat energy stores can last a long time. But fat metabolism is slow to get going. Glucose, on the other hand, is metabolised for energy much faster. As a result, during vigorous exercise, glucose is the main energy source. However, our glucose stores, found mainly in the liver and muscles, are limited. One’s glucose stores may be depleted following 90-120 minutes of exercise. Therefore, with continued longer exercise, your body will run out of glucose for energy and it will need to be replaced.
A number of studies suggest sports drinks may improve exercise performance (<10%) in short-term (about 60 minutes), high intensity (80% to 90% max) exercise. However, not all studies demonstrate a benefit, and some suggest water is just as effective. Many of these studies were conducted in trained athletes who were conditioned to exercise at very high levels. In addition, athletes in the studies either underwent fasting or a dehydrating exercise session to deplete glucose stores before the test exercise. While these methods are effective at determining whether sports drinks can replenish glucose, they don’t reflect the real-world types of exercise most people do.
The findings from short-term exercise studies go against the fact our body has more than enough glucose stores to get through these short sessions. It’s possible ingestion of glucose may get the sugars into the blood stream faster than stored glucose can be delivered to the working muscles. However, direct infusion of glucose into the blood during a 60 minute exercise session did not improve performance compared to a water control.
Further studies have looked into what’s now called “carb rinsing”. A practice in which a mouthful of sports drink is swished without swallowing it. This is commonly done among professional soccer players. It’s based on studies suggesting performance was best when participants swished the sports drink in their mouths compared to water or when the drink was swallowed. A later study reported swishing the drink for 10 seconds during short-term exercise resulted in better performance compared to 5 seconds or swishing with water only. It’s believed the sensation of sugars in the mouth stimulates the brain to be primed for more energy release. However, this finding isn’t consistent among all studies.
At some point, with longer exercise, you will need to replenish both glucose and water. And doing so in a drink is often easier while exercising than combinations of food and water. A review of 19 studies found sports drinks increased time to exhaustion >40% during exercise lasting an average of two hours or more. And tennis players had less indicators of fatigue in their arm muscles when using a sports drink. However, while glucose and water will likely need to be replenished, they don’t need to come from commercial sports drinks.
With sports drinks becoming so popular, concern has turned to the possible impacts on health and weight. Interest has focused more on children given their high consumption, often outside of any exercise session. While sports drinks have half as many calories per volume than soda pop, they’re sold in much larger volumes. For Gatorade it’s commonly 591 mL (142 calories) and for Powerade it’s 710 mL (150 calories) per bottle. This compares to 355 mL for a can of pop (150 calories).
While many studies on health risks lump sports drinks with other sugar-sweetened beverages, sports drinks on their own have been associated with weight gain in teens. There is also concern regarding the frequent use of sports drinks on tooth decay. As a result, the American Association of Pediatrics recommends limiting sports drinks to athletes during prolonged bouts of vigorous exercise and promoting water as the main source of hydration.
More recently, sports drinks are available in low or zero-calorie formulas. These are basically coloured water with electrolytes added (sodium being the predominant one). The premise is that one loses electrolytes through sweat while exercising, which also need replenishing. However, evidence to suggest electrolyte drinks improve performance is lacking. Added to this is the wide variation in the amount of electrolyte loss between people and the dependency on weather.
A study of 174 ultra-marathon runners found proper training and balanced hydration (not over or under hydration) were more strongly associated with sodium balance after a race than sodium supplementation. This may reflect the improved conditioning from training but also the experience gained in learning what source of fluids, energy and electrolytes work best for them.
As most exercise sessions last less than an hour and are usually performed at a moderate intensity, sports drinks aren’t needed, and the excess sugar and calories may do more harm than good. For longer exercise, you will likely need some sort of energy replacement. However, this doesn’t mean you need to turn to a sports drinks. Use your training sessions to figure out what works best for you. It could be the convenience of a sports drink. Or your own homemade concoction of sugar and fluid, or flat Coke as some athletes use. Or even a mix of food and water.
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