| Sports Drinks: To Drink, Or Not To Drink |
|
| Written by Dr. Dennis Bobilya | |
| Monday, 14 July 2008 19:07 | |
|
Mark groaned as he struggled to raise the barbell for an eighth rep. He grimaced in frustration as he finished a second set and took a sip from his bottle of pure water. He was still lifting the same weight as four weeks ago, even though he’d been working out coming to the gym three mornings each week before breakfast. On the other side of the room, Heather was pounding out the miles on a treadmill. She watched the screen in front of her count the calories she was burning while sipping a second bottle of Gatorade sports drink. “I’m burning the fat now,” she thought. “I’ll fit into my mother’s wedding dress, for sure.” What’s wrong with this picture?
Both of these scenarios illustrate confusion about when a sports drink is beneficial: Mark should be drinking a sports drink rather than water. Heather should be drinking pure water. Would you like me to explain?
Most athletes acknowledge that hydration is important. But there is confusion about which fluid to hydrate with. Some athletes have heard that water is as good as a sports drink. Some have also heard that sports drinks can make you fat. Both of these statements are true and false, depending on the situation.
Much of the nutritional guidance in the popular media is targeted to the general population. Most people are sedentary or engage in only light exercise. Their nutritional needs are very different from those of athletes in pursuit of peak performance. As a friend of mine, Dr. Sam Smith, would say, “athletes are like Ferraris and the rest of us are like Fords and Chevies. Athletes need high octane fuel.” The sports drink vs water decision is an excellent example of this dichotomy of recommendations. Sports drinks can be very beneficial for elite endurance athletes. Sports drinks are formulated to provide the fluid, energy, and minerals they need to sustain their athletic prowess. For non-athletes, water is the best beverage and sports drinks are empty calories, very similar to fattening, sugary soft drinks (soda pop).
Gatorade was created in 1965 by a team of sports physiologists at the University of Florida. The Gators football team was struggling to stay hydrated and energized during summer practices. The original recipe used to ‘aid’ the ‘gators’ continues to be supported by more recent scientific research. The physiologists knew that one liter (about one quart) is the maximum amount of water that most people can absorb in one hour while exercising. Likewise, 60 grams of glucose is the maximum amount that could be absorbed in one hour. So, Gatorade was formulated to contain 60 grams of glucose in one liter of water (6% glucose). The athletes were advised to drink one liter per hour for maximum benefit. This would provide the maximum amount of glucose and water the athletes’ bodies could accommodate. The original formula also contained some sodium and potassium to replace these minerals that are lost in sweat. These minerals (called electrolytes or salts) also serve to encourage water absorption by the body.
Today, there are dozens of different sports drinks with a range of carbohydrate and mineral concentrations. Some also have a variety of other components, such as caffeine, creatine, vitamins, and antioxidants. The components of sports drinks will be evaluated in this article so you know what to look for. But, first, I’d like to return to the question of when is a sports drink more beneficial than water. And, when is pure water preferred.
When is a sports drink more beneficial than water? The principal ingredients in a sports drink besides water are minerals and carbohydrates. These minerals (primarily sodium and potassium) leave the body along with our sweat. Any athlete who sweats a lot might benefit from replacing these minerals during exercise. Athletes frequently underestimate the amounts they sweat. Athletes that train hard for more than an hour each day, especially when in hot climates, would probably benefit from some mineral supplementation during exercise. While the general population usually obtains sufficient amounts of these minerals from a balanced diet, intensively training athletes may not get enough in the diet to replace the large amounts lost in their sweat.
Carbohydrates are included in sports drinks because carbohydrate depletion is the most common cause of fatigue in athletes (see Why Athletes Fatigue). Athletes employ several strategies to delay carbohydrate depletion. One strategy is to consume carbohydrates during physical activity. The carbohydrates could be obtained in foods or beverages. Beverages are often more convenient. They also provide water, thereby resolving two challenges simultaneously.
Athletes begin their physical activity with a fixed amount of stored carbohydrates. Sometimes those stores are plentiful, such as after a carbohydrate-rich meal. At other times the carbohydrate stores are meager, such as when nothing has been eaten for several hours. An example of this would be Mark, the athlete mentioned in the beginning of this article. He was weight training before breakfast. Athletes who begin their training session or competition with low carbohydrate stores would benefit from consuming supplemental carbohydrates during the event. This might be true for even a 20 minute work out. It would depend on how low the carbohydrate stores were.
The amount of carbohydrates that a body can store is limited. There is a maximum. For most athletes, this maximum is about one pound. Some elite athletes can train their bodies to store up to two pounds. Whatever the amount, it will eventually run out when you train or compete for an extended period. So, another group of athletes likely to benefit from carbohydrate consumption during an event are those whose carbohydrate stores could not suffice even if the stores were maximized. A good example of this would be long-distance cyclists, who may cycle for 3-5 hours. Sports nutritionists generally recommend supplemental carbohydrates (like sports drinks) for well-nourished athletes if their event lasts longer than 90 minutes.
Supplemental carbohydrates during an event will not increase your energy at the beginning of the event. You will not run faster or jump higher. But you will be able to run longer at your chosen speed. This is like when you add gas to your car’s tank during a trip. The additional gas will not make you drive faster, but it will enable you to drive longer. What if the gas gauge is broken? Wouldn’t you think it wise to add a little gas for insurance? We usually don’t know the amount of our carbohydrate stores. Sometimes we also don’t know how long the event will last. What if the game goes into overtime? Why risk running out of carbohydrates when the consequences can be so catastrophic? This is why I recommend that all athletes who want peak performance to consume carbohydrates during all trainings and competitions – usually as a sports drink.
Begin drinking sports drinks before you begin the intense activity (during or after warming up) and continue drinking them throughout. Don’t wait until your carbohydrate stores run low. Add ‘gas’ to your tank continuously, so the total added is greater. The more you add, the longer you can go before running out.
Some athletes use a sports drink during an important competition, but not during training. This is a rooky mistake. Delaying fatigue is just as important during training as it is during competition. How else can an athlete improve performance? Athletes should follow a hydration plan with sports drinks during training sessions that closely mimics how they plan to drink during a competition. This enables athletes (and their trainers and coaches) to evaluate their hydration plan and their chosen sports drink for effectiveness. Adjustments can be made to the plan prior to important competitions. Practice your drinking of sports drinks until you’re satisfied with your athletic drinking skills.
When is water more beneficial than a sports drink? Water is your best beverage when you only want to hydrate, when you are completely confident that your body’s mineral and carbohydrate stores are sufficient to last through the event. An example of this might be running or cycling for 30 minutes in the evening when you’re well-nourished. Plain water would also probably be sufficient during a 5K footrace, assuming you’re well-nourished. If you’ve been eating a carbohydrate-rich, well-balanced diet over the previous few days, your carbohydrate stores should be sufficient to sustain you for at least 45 minutes, so a sports drink would be redundant. The carbohydrate stores of many well-nourished athletes might even last for 75 minutes. Or, maybe even 90 minutes. But, I don’t recommend taking that risk if you want to be competitive.
Water would also be your preferred beverage if the goal of the physical activity is to reduce body-fat. In this instance, the sports drink would be additional calories and would undermine your goal. The extra calories of the sports drink would slow the rate at which the body-fat is being used to fuel the activity. Of course, your athletic performance will suffer if your body’s carbohydrate stores run low during your exercise. You may feel a greater sense of fatigue. So, you should not drink plain water if your goal is to improve your performance, or if you dislike that feeling of fatigue when you’re exercising. Heather (from the opening paragraph) was happily working away because the sports drink was supplementing her energy, but she would have been burning more body-fat without it. If you’re not concerned about your performance, and reducing body-fat is your primary goal, then water would be your best hydration beverage, no matter how fatigued you get. (This does not include exercise lasting more than two hours in hot weather, when mineral replacement might be needed.)
Water is usually your best beverage whenever you are not exercising (except of course during breaks in the action). This includes when you’re watching from the sidelines, as well as from the couch at home. Never drink a sports drink while inactive, except in the following exceptions. One exception would be immediately before or immediately after exercising. Another exception might be if you can’t consume sufficient carbohydrates from natural food to meet daily needs. Women tend to have smaller stomachs and may not be able to eat enough. Endurance athletes may also have difficulty consuming enough carbohydrates from food. So, there are some athletes, such as women cross-country runners, who might benefit from the additional carbohydrates throughout the day. For supplemental carbohydrates while at rest, try to avoid beverages high in fructose. The better ones have glucose and dextrin (see below). Other than these few exceptions, it’s generally unwise to consume sports drinks when not engaged in a sport.
Athletes should not drink sports drinks during the off-season, or whenever they’re not training hard. Dinking sports drinks or any other sugary drink when you’re not physically active can increase body-fat deposits. What’s the big difference due to the physical activity? When you’re engaged in physical activity, all the carbohydrates tend to go directly to the working muscles. None will go into storage. When you’re sedentary, up to half the sugary carbohydrates may be converted to fat. Most of the other half of the carbohydrates will go into carbohydrate stores.1 Another concern with drinking sugar-water when it’s not justified to enhance athletic performance is the needless increase in dental cavities.
How much carbohydrate? The concentration of carbohydrates in sports drinks usually ranges between 4-8%. This percentage is not indicated on the label. Instead, the Nutrition Facts label indicates the quantity (in grams) of carbohydrates in a serving (usually 8 or 12 oz). Ignore the percentages listed under % Daily Value. The standard goal for most athletes (whenever possible) is to drink 8 oz of fluid with 15 grams of carbohydrate every 15 minutes (22 grams in a 12 oz serving). Most sports drinks have 14-16 grams per 8 oz serving, though they can range from 10-20 grams. Why the range? The goal is to get as much carbohydrate as possible, so higher amounts would be better if tolerated. However, there’s a lot of variation among athletes. Some athletes can drink a beverage with 30 grams of carbohydrate in 8 oz, while others feel even 10 grams per 8 oz is too sweet, and makes them gag. High fructose corn syrup is especially sweet. Sweet things taste even sweeter during exercise in some athletes. If it’s too sweet to drink, then find one that isn’t or dilute a full-strength sports drink with plain water until an acceptable sweetness is reached. Remember: More is better, but anything is better than nothing.
Which carbohydrate? The carbohydrates in sports drinks are usually simple sugars. They are primarily glucose, fructose, and sucrose. There is some evidence that a mixture of glucose and fructose is optimal for endurance athletes. The explanation is that the glucose is absorbed very quickly and provides an immediate boost in blood glucose. The fructose is absorbed more slowly. The fructose must then be converted to glucose by the liver before it can contribute to blood glucose. (Muscles don’t use fructose.) Thus, the effect on blood glucose is longer with less of a spike. Sucrose is equal parts glucose and fructose. It is commonly called table sugar or sucrose syrup and comes primarily from fruit. Most sports drinks of the 21st century contain high fructose corn syrup (HFCS). HFCS is the inexpensive sweetener used in soft drinks. It is made by converting some of the glucose in corn sugar (which initially is almost all glucose) to fructose. So, HFCS has about equal amounts of glucose and fructose. This nutrient composition is similar to sucrose (table sugar), but HFCS is much cheaper because it’s made from corn rather than fruit. It’s also sweeter than table sugar. Sometimes, sports drinks may contain maltose, dextrin, or maltodextrin. These are complexes of glucose molecules connected together (without fructose). These larger complexes of glucose are especially useful when the carbohydrate concentration gets above 8% because they remain dissolved better than simple sugars do at the higher concentration, and are less likely to cause discomfort. Digestion of the glucose complexes into individual glucose molecules occurs so rapidly that the absorption rate is the same as pure glucose: 10-20 minutes if in liquid form on an empty stomach (food slows digestion). Which carbohydrate is best? I generally prefer glucose or glucose complexes (partly because they’re not as sweet), but the glucose-fructose mixtures work well enough and they tend to be cheaper.
How much minerals? The most common minerals in sports drinks are sodium, potassium, and magnesium. All three are lost in sweat. All three are important in muscular contractions. Depletion can cause muscle fatigue and cramps. A well-balanced diet should provide sufficient minerals to replace those lost through sweating for most athletes. Only a relatively few athletes who sweat a great deal may require additional minerals during exercise. Nevertheless, nearly all commercial sports drinks include some minerals. These minerals are inexpensive and there’s no downside to getting a little extra (unless your doctor insists you follow a low sodium diet). The inclusion of some minerals in sports drinks also enhances water absorption from the beverage.
Sodium is the most important of the major minerals for athletes. Sweat losses vary, but an athlete engaged in intensive athletic activity could lose about 2,000 milligrams (mg) of sodium in sweat each hour.2 Elite athletes may train 2-5 hours each day. This would result in the loss of 4-10,000 mg of sodium per day. The ‘typical’ American diet provides 6-9,000 mg daily. So, whether an athlete needs supplemental sodium during exercise might depend on how ‘typical’ their diet is. Some athletes think a low sodium diet is good for them because it’s good for the general public. But a low sodium diet can be harmful to an athlete who sweats a lot.
Sports drinks commonly contain about 100 mg per 8 oz serving (150 mg in a 12 oz serving). Since these athletes are drinking 8 oz every 15 minutes, they would receive about 400 mg each hour. Not nearly enough to replace 2,000 mg per hour, but a good start. If you tend to sweat a lot, you may want to find a drink that is higher in sodium: Some ‘endurance’ sports drinks provide up to 200 mg per 8 oz serving. Use caution though, because you may notice that water absorption slows at higher concentrations. An alternative is to be a little more generous with the salt shaker at mealtimes.
Sports drinks usually contain a small amount of potassium. They sometimes (rarely) contain magnesium. If added, then potassium and magnesium are present in relatively small amounts. These two minerals are abundant in the diets of most people. Potassium is found in all foods, but is especially abundant in avocados, bananas, orange juice, and tomato juice. Excellent food sources of magnesium include potatoes, whole grains, and nuts.
Other additives Amino acids, vitamins, antioxidants, creatine, and caffeine are some of the other additives found in some sports drinks. There is some evidence that suggests that each of these might benefit some athletes. However, in general, these are not beneficial for most athletes. Neither are they likely to be harmful. So, they shouldn’t have a significant role in your considerations about sports drinks. I’ll evaluate these additives more thoroughly in a future article on sports supplements.
Home recipes Sports drinks do not have to be purchased. You can make your own at home. The main ingredients are 15 grams carbohydrate in 8 oz of water. A simple sports drink might be fruit juice, which is typically about 25-30 grams of carbohydrate per 8 oz, diluted with an equal volume of water (1:1 dilution). This applies to most fruit juices, including orange, apple, and cranberry.
You can also make your own from common ingredients. One tablespoon of table sugar (12 grams) or honey (17 grams) in 8 oz of water would work nicely. Increase the sugar/honey up to two tablespoons per 8 oz if you prefer. Add a ‘dash’ of table salt to add 100-200 mg of sodium. Add a few drops of lemon juice for flavor.
Which sports drink is best? Technically, the best sports drink is the one that enables you to consume the most carbohydrates. Usually, this means those with the higher carbohydrate contents. But, in my experience with athletes, the best sports drink for you is the one you think tastes the best. Research has shown that athletes voluntarily drink more fluids if they are flavored and cool, but not too cold. The differences in nutritional composition between sports drinks won’t matter if they’re not drunk. What’s most important is that the beverage has some carbohydrates, any carbohydrates. And that you drink it!
Concluding summary In summary, competitive athletes always consume a sports drink whenever training or competing. They practice their drinking skills during training sessions in preparation for important competitions. They drink about 8 oz every 15 minutes, whenever possible. Their beverage contains about 15 grams of carbohydrate and 100 mg of sodium in 8 oz. The taste of the sports drink encourages consumption. Drinking with discipline will helps these athletes achieve their full athletic potential.
Summary Recommendations: Drink ½ quart (16 oz.) of sports drink15 minutes prior to the event (after or during warm-up). Drink 6-8 oz every 15-20 minutes of play whenever possible (a mouthful is about 1 oz.) Drink ½ quart (16 oz.) of sports drink within 15 minutes after the event (during cool-down). Drink water the rest of the day, unless there is doubt about whether sufficient carbohydrates can be obtained through your carbohydrate-rich diet.
For those who want to know more 1 Insulin is the powerful hormone that directs the macronutrients (carbohydrates, fats, proteins) to their metabolic fate. Insulin rises after eating or drinking carbohydrates. Exercise lowers insulin. Most sports drinks have nearly-equal amounts of two carbohydrates: glucose and fructose (added as sucrose syrup and high fructose corn syrup). All glucose is used as an immediate energy fuel or else it goes into carbohydrate storage. Glucose is almost never converted to fat in athletes training more than an hour each day. All fructose, on the other hand, goes to the liver. During exercise, when insulin is low, even after drinking carbohydrates, the liver converts the fructose to glucose and the glucose is released into the blood to support the muscles and organs. Fructose cannot be used by the rest of the body. At rest, when insulin is high after drinking carbohydrates, the fructose is converted to fat. This is how fructose in table sugar and high fructose corn syrup can promote fat gain in sedentary individuals.
2 The amount of sweat an athlete loses varies, ranging from 1-3 quarts each hour. Sodium losses range from 1,500 to 4,500 mg/hr. Higher amounts of sweat and sodium are lost in hot and humid environments. Higher amounts are lost if the athlete is not acclimated to the heat and humidity. Higher amounts are lost at higher exercise intensities. Higher amounts are lost in untrained athletes. The sweat rate declines as the athlete becomes dehydrated during exercise.
Add your comment |