Can we go farther on less sugary sports drinks?
Salute your bike helmet if you do this: Flip to the "calories" display on your hear monitor watch more often than the heart rate. Come on. Admit that seeing the calorie burn helps you keep working and sweating and gulping down sports drink.
And then what? Ooh la la. Finally, goal achieved. Time to head home for a shower and some well deserved chow.
Research has proven time and again that supplying carbohydrate and fluids during exercise will improve performance time to exhaustion. There is a part of me, however, that resists putting a sugar laden beverage into a sport bottle to drink. I think about how much sugar I consume over a two-hour ride, which can easily surpass 80 grams and add up to 300 calories. Is there another way to get the job done?
It seems I am not the only one concerned about the amount of sugar and calories consumed during exercise, based on the number of reduced carbohydrate sport drinks that have recently been marketed to athletes. Virtually every major sports nutrition company has gotten into the lower calorie game, with products like Propel, G2 Low Cal?, AllSport Zero? and PowerAde Zero. Then there are low-carb-plus-protein drinks, such as Accelerade Hydro and Pure Sport Workout?.
Where do these sport drinks fit in to an endurance athlete's training plan? Less sugar sounds like a great idea, but as one of my biker friends asked, "Can the gals still expect to 'kick it' at the end?"
Fortunately the field of sport nutrition has evolved since the days when athletes were encouraged to tough it out and go without fluids during exercise. Guidelines from the American College of Sports Medicine (ASCM) and American Dietetic Association (ADA) can help ensure athletes exercise safely and optimize performance. Let's see how the newbies fit in.
Water: The original zero-calorie drink
You're heading to the gym for a quick "pump" class or going out for a 45-minute tempo run. What is a good fluid choice? The ASCM suggests athletes can use water instead of a traditional 6- to 8-percent carbohydrate sports drink under these conditions: exercise is less than 60 minutes, a pre-exercise meal or snack has been consumed, and the athlete is well-conditioned and hydrated at the onset of exercise. Do you meet those criteria? Then fill up your water bottle. Price: cheap.
The next step up from water is the new zero-carb or low-carb sport drink. Most contain moderate amounts of sodium and potassium plus a little flavor. The ACSM guidelines encourage athletes to consider their individual needs when deciding if a zero calorie sport drink is a better choice than water.
Some factors to consider: Ambient temperature, level of acclimation to heat, duration of exercise, and whether a pre-exercise snack or meal has been consumed. Even if exercise is less than 60 minutes, a high sweat rate indicates the need for fluid and sodium replacement. For $1.50 to $2.00 per bottle, the zero calorie sport drinks can provide both, without added calories.
The right drink for long workouts
Most endurance athletes do exercise for longer than an hour on a regular basis. John Ivy, PhD., at the University of Texas-Austin, has done research since the early 1990s with athletes evaluating the effectiveness of sport hydration and recovery drinks on performance and muscle metabolism.
"Regardless of which product you choose," Ivy says, "the overall goal of a sport drink should be to maintain the body's chemical balance and provide a steady energy supply during exercise."
Providing a steady energy supply has traditionally been done with carbohydrates, primarily simple sugars. Sport drinks were originally made by Gatorade? - basically a white sugar and water recipe, with a modest amount of sodium and potassium. This basic formula worked, but has been fine tuned over the years as the understanding of hydration and energy during exercise grew.
The most recent ACSM guidelines state that a mixture of different types of sugars with a concentration of 6 percent to 8 percent is the best way to maintain hydration and provide energy to muscle during exercise. The benefits to delivering glucose efficiently during exercise are many, including reducing stress on the immune system, reducing perception of fatigue and minimizing muscle protein breakdown during exercise.
The quest for finding the ultimate fuel during exercise is as competitive as the athletes who use them, however. By adding protein to a carbohydrate drink, lead researcher Michael J. Saunders, PhD, from James Madison University in Harrisonburg, Virginia, found in 1994 that cyclists were able to ride 29 percent longer at a high intensity compared to a carbohydrate-only traditional sport drink. A bonus from adding protein to the drink appeared to be less muscle damage from the exercise. Now athletes had another option to use for long duration events, and products with protein began to be developed and promoted as superior to carbohydrate based drinks.
While the advantages of using a carbohydrate-plus-protein drink were appealing, many athletes found that the carb-plus-protein drinks were unpalatable. In fact, one of the criticisms of the carbohydrate-plus-protein drinks was they were actually higher in calories than most straight carbohydrate based drinks. Could the performance benefits simply be that more calories per ounce were being consumed?
High carb drinks not required
"We had been experimenting with a reduced carbohydrate-plus-protein drink, but had not been successful," Ivy says, "so we changed the 3 percent carbohydrate source to a mixture of sugars."
Published in The Journal of Strength and Conditioning Research, a study done by a Ivy and his fellow researchers caught my eye. It involved 14 well-trained female cyclists and/or triathletes who were asked to perform two trials, cycling for three hours at intensities varying between 45 percent of VO2max and 75 percent of VO2max, followed by an all-out effort until they could not maintain a pedal cadence of 60 rpms (defined as the time to exhaustion).
During the trials, either a 3 percent carbohydrate-plus-protein drink or a traditional 6 percent carbohydrate sport drink was consumed. When the two trials were compared, the athletes who consumed the 3 percent carbohydrate-plus-protein trial showed a 15.2 percent improvement in their time to exhaustion over the 6 percent carbohydrate trial subjects.
Commenting on the results of the study, Ivy stated via email, "The right protein-to-carbohydrate ratio is essential. Equally important is the mixture of sugars rather than a single sugar as a carbohydrate source because the combination of glucose, fructose and maltodextrin will enter the circulation faster and be more effective than a single sugar source."
The choice remains
During bib pick up the night before a 50-mile mountain bike race last summer, I did some random surveying of athletes about what their hydration plan was for the event. The weather the next day was predicted to be unusually hot and humid. I was appalled at how many of the novice racers were planning to drink only water. Their reasoning? "I always drink just water."
Choosing a sport drink to maintain hydration and chemical balance is like buying the right bike or pair of running shoes. Athletes need to consider their individual genetics, as well as the conditions the drinks will be used under. Ignorance or denial of the physiologic demands of exercise in an outdoor environment can be serious, even fatal. Read up on what to use when, and then put it to the test.
Donna Marlor, MA, RD, CSSD, is a registered dietician specializing in nutrition for endurance exercise and weight management. She offers motivational coaching and behavioral skills training to change eating patterns. Marlor is a consultant to the Olympic Education Center in Marquette, Michigan, and works with many individual athletes from novice to elite. A former collegiate alpine and Nordic skier, Marlor still enjoys master's level competition as a skier and runner as well as spending time with her family and chocolate Lab in the Upper Peninsula. She can be reached via www.DonnaMarlor.com and at 906/360-9049.