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The triathlon is a unique sport in that it combines three disciplines: swimming, cycling and running. Triathlon competitions can last less than an hour (i.e. super-sprint and sprint distances) or in the case of Ironman distances, the world’s very best triathletes require over 8 hours to complete a course. The physiological demands and nutritional challenges of the triathlon obviously depend on the duration of the event – for long-distance events those demands and challenges are formidable.
The most important energy sources utilized during endurance exercise are bundles of glucose found in muscle called glycogen, as well as the glucose that circulates in the bloodstream. Although well-trained triathletes are often able to compete at high intensities even after muscle glycogen stores are theoretically depleted, fatigue during an event is primarily related to muscle glycogen stores hitting empty, as well as declining concentrations of blood glucose. Therefore, triathletes striving for their best athletic performances benefit from a strategic approach to carbohydrate intake in the days, and even hours, before an event to boost and maintain high glycogen levels.
Exercise physiologists call it muscle glycogen supercompensation. Athletes call it carbo-loading. No matter what you call it, the idea is to maximize the amount of glycogen stored in your muscles just prior to a competition. The prevailing thinking is that well-trained triathletes preparing for Olympic- or Ironman-distance triathlons (i.e. events lasting more than 90 minutes) can improve performance by 2-3% by following a carbo-loading regimen. There’s probably little to no benefit to carbo-loading for events lasting less than 90 minutes.
The “classic” approach to muscle glycogen loading involves an exhaustive bout of exercise to deplete muscle glycogen stores, followed by three days of a low-carb diet and then three days of a high-carb diet. This nearly 40-year old regimen typically doubles muscle glycogen stores, but it’s extremely arduous and puts athletes at risk of injury.
Fortunately, less drastic approaches to muscle glycogen supercompensation have been developed. In the early 1980s, the favored approach to carb loading was three days of a moderate-carb diet (about 5 grams of carbs for every 2.2 pounds of body weight), followed by three days of a higher-carb diet (about 8 grams of carbs for every 2.2 pounds of body weight) combined with a tapered training regimen. In the last few years, scientists have found that high-carb diets (about 12.5 grams of carbs for every 2.2 pounds of body weight) during 6 consecutive days of training can lead to extremely high muscle glycogen concentrations. These high glycogen levels can be achieved without an exhaustive bout of exercise and without the need for tapering training.
In an even newer carbo-loading iteration, scientists have developed carbo-loading lite, a one-day carb-loading regimen that is as effective as the harder-to-follow older methods. The new method calls for consuming 10.5 grams of carbs for every 2.2 pounds of body weight the day after either a short-term, high-intensity exercise bout, or on a rest day following a typical week of training. When tested on athletes, the one-day approach resulted in supercompensated muscle glycogen stores within 24 hours.
This is important because the one-day protocol allows athletes to follow their normal training preparations right up until the day before a competition. Scientists also found that for those who can’t consume a high-carb diet the day before a race, the one-day loading protocol can be initiated several days before the competition. If followed by rest and a moderate-carb diet (4-5 grams of carbs for every 2.2 pounds of body weight), the resulting supercompensated glycogen levels can be maintained for at least three days.
So, if you are a triathlete interested in achieving high muscle glycogen stores prior to your next event, make sure your carb intake is high (about 10.5 grams of carbs for every 2.2 pounds of body weight) for at least one day before your event. In addition, somewhere in the 3-4 days leading up to your event, be sure to significantly reduce muscle glycogen stores either through a longer training session at moderate intensity or through a short-term, high-intensity training session.
Carbs consumed prior to exercise help to enhance the availability of muscle fuel by increasing muscle and liver glycogen stores before exercise, or by providing a source of glucose in the digestive tract for later release into the bloodstream. Overnight fasting will substantially deplete liver glycogen stores, so the pre-event meal helps compensate for this. In addition, a pre-event carb-rich meal or snack may be an important window of opportunity for those triathletes who can only tolerate small amounts of carbs in solid or liquid form during exercise. Consuming roughly 200-300 grams of carbs 3-4 hours before exercise is an effective strategy for enhancing carb availability during subsequent exercise. Of course, the trick is to choose carb sources that are easily digested and don’t cause gastrointestinal discomfort. So, be sure to test your pre-event carb meal or snack during training so that you don’t end up surprised on the actual day of the event.
The benefit of carb ingestion in the hour before a triathlon is a matter of some debate and probably comes down to individual preference. The quick rise in blood sugar that occurs after carbs are ingested is followed shortly thereafter by a drop in blood sugar. The blood glucose decline has raised concern about possible detrimental effects on exercise performance. However, to date, research suggests that these fluctuations in blood sugar don’t seem to have an impact on exercise performance. Thus, there doesn’t appear to be a need to avoid carbs in the hour before your event, and if you like nibbling or munching while you’re waiting in the starting area, experiment during training to see what approach to timing of intake leaves you feeling the best.
While carb intake before a triathlon is intended to boost your glycogen stores, carb intake during a competition is all about sparing your limited reserves of muscle glycogen. It’s well established that carb intake during exercise lasting more than an hour improves endurance capacity by maintaining both glucose levels in the bloodstream and the high rate at which carbs can be burned as muscle fuel.
So, when is the best time to consume carbs during competition? In a study of athletes competing in an Ironman-distance event, carb intake was three times higher during cycling as compared to the running leg. And of course, no consumption took place during the swimming leg.
Because triathletes are faced with a limited opportunity for carbohydrate intake during an event, attention to sources of carbs becomes even more important. Recent research has shown that a mixture of glucose and fructose leads to 20-50% higher rates of glycogen burning compared with ingestion of an equivalent calorie level of glucose alone. This is probably because glucose and fructose have separate transport systems within the digestive tract, and by providing some of each type, more total carbs can be absorbed and made available to serve as muscle fuel. Overall, carbs should be ingested at a rate of about 60-90 grams every hour during exercise. POWERBAR® Endurance products like POWERBAR® Beverage System Performance Sports Drink and POWERBAR® Gel take advantage of the body’s natural dual transport capability by providing a blend of glucose and fructose sources for faster energy delivery.
Avoiding dehydration and overhydration during a triathlon is important both for health and athletic performance. One-size-fits-all fluid intake recommendations are quickly becoming a thing of the past as they can lead to overconsumption (hyponatremia) or underconsumption (dehydration). Instead, the latest sports medicine recommendations for optimal hydration call for tailoring your fluid intake during exercise to your sweat rate. That means triathletes should be weighing themselves before and after training and competitions with the idea of losing no more than 1% of body weight during exercise, and adjusting their fluid consumption in their next exercise bout accordingly.
Triathlons pose unique challenges to hydration. Fluid intake during the swim phase of a triathlon is not possible and over-consuming fluids during the run can cause gastrointestinal symptoms. Thus, just like with carb delivery, the cycling leg represents the best opportunity for fluid ingestion. On the bike, fluids are easier to access and ingestion is usually the least disturbing to performance. That said, over-consuming fluids while on the bike could leave you with too much fluid in the digestive tract when it’s time to transition to the run. The resulting abdominal fullness and bloating can lead to nausea. This again underscores the importance of actively hydrating whenever you can during a competition, and tailoring your fluid intake to limit weight loss during exercise to no more than 1% of body weight.
For hydration purposes, a well-designed sports drink is superior to water for triathletes. The reason for this is that glucose is actively absorbed when ingested and sodium helps in this process. In turn, fluids follow the absorbed glucose and sodium. Thus, a sports drink with carbs and sodium is widely recommended to enhance fluid absorption. Also, research shows that athletes naturally consume more fluid when it is in the form of a flavored sports drink as compared to plain water. Finally, there is an optimum carbohydrate concentration in a sports drink. In the range of 5-8% (50-80 grams of carbs per liter of sports drink) is ideal. Too few carbs means you’re not maximizing your opportunity to fuel muscles, and too many carbs can slow the absorption of fluids. POWERBAR® Beverage System Performance Sports Drink features a 7% carb concentration, which is in the upper-end of the recommended range for optimal hydration.
There are essentially two goals for recovery after a triathlon or strenuous day of training: replenish muscle glycogen stores depleted during exercise and rehydrate to make up for fluid lost.
Provided that you consume about 8 grams of carbs for every 2.2 pounds of body weight in the 24 hours after competing, it’s likely that you will achieve complete restoration of glycogen stores within those 24 hours. As long as carb intake is adequate, ingesting fat and protein along with your carbs doesn’t detract from recovery. Frequency of intake over the first 24 hours after an event doesn’t impact recovery as long as the total carb intake is sufficient. So, if you find it hard to eat much right after an event, or there just isn’t much available to eat, don’t panic. You can delay eating by a few hours without seriously compromising recovery. Also, foods and beverages with moderate to high glycemic index are recommended after exercise because they may produce higher rates of glycogen synthesis than low glycemic index foods.
One more thing: glycogen synthesis is impaired for several days after muscle-damaging exercise, such as after running a marathon distance. So, if your event includes a long running stage, complete recovery of glycogen stores may take longer than 24 hours despite the intake of a high-carb diet.
While most triathletes don’t compete on two consecutive days, many triathletes often train more than once a day. In this scenario, faster recovery is the goal. The highest rates of muscle glycogen synthesis have been found in studies where carb feedings were provided every 15-20 minutes in the first few hours after exercise. Also, glycogen synthesis rates were almost twice as high when carbs were ingested immediately after exercise as opposed to waiting a few hours. So, if fast recovery is needed, carb-up as soon as possible after exercise, and keep the carbs coming at frequent intervals. Carbs in liquid and solid form are both fine for reloading glycogen stores. However, liquid versions offer the advantage of also providing fluids for rehydration. In addition, if your appetite is suppressed after exercise, drinking fluids may be more appealing than eating something solid.
Triathletes, like almost all athletes, are often intrigued about the role of protein during recovery. Here’s the scoop: protein and carbs together can increase muscle glycogen synthesis rates by 40-100%, probably by stimulating insulin secretion, which has a natural anabolic effect. However, if carb intake is high to begin with (i.e. 1.2 grams of carbs per hour for every 2.2 pounds of body weight), then the addition of protein doesn’t boost glycogen synthesis rates any further. Nonetheless, having some protein in combination with carbs after exercise may increase protein synthesis and promote faster tissue growth and repair after a tough day on the course. Theoretically at least, this might be helpful for events that involve long-distance running segments known to induce significant muscle damage. POWERBAR® Beverage System Recovery Sports Drink features both carbs and protein. The carbs help rebuild glycogen stores and the protein serves a dual purpose of promoting faster glycogen synthesis and helping in the repair of muscles.
Restoring fluid balance after exercise is also an important part of recovery. Water is not the most effective rehydration beverage. Ingestion of plain water increases urine output and is less effective at restoring fluid balance as compared to a sports drink that includes carbs and sodium.
Gastrointestinal complaints like nausea, vomiting, abdominal and stomach cramps, diarrhea and dizziness are very common among triathletes. The running leg is where problems occur most often. Since running is typically the final event of the triathlon, the complaints may be due to the duration of the exercise. However, a good portion of the complaints probably stem from excessive movement within the digestive tract. Avoiding excessive fluid consumption late in the cycling phase of competition may help. In addition, problems may be more likely to occur with the ingestion of foods containing harder-to-digest fiber, fat and protein. Beverages that are too high in carb concentration can also be the culprits. Finally, nutrition isn’t always to blame. During intense exercise, blood flow to the digestive tract can be reduced by 80% or more. The lack of blood flow to the gut may be a contributor to gastrointestinal symptoms in ways that are not yet well understood.
Whether you’re contemplating your first triathlon, or you’re a veteran wondering if you’re doing everything you can to perform at your best, PowerBar has cutting-edge sports nutrition products and resources to help you be your best.
POWERBAR® products are designed to meet your needs before, during and after training and triathlon competitions. Products like POWERBAR® Performance bars, POWERBAR® Gel and POWERBAR® Beverage System sports drinks are all athlete-tested and based on the latest recommendations of sports nutrition authorities. Easy-to-absorb ingredients, properly concentrated carb and electrolyte sources, science-based mixtures of carbs and protein, and innovative carb blends deliver the maximum energy to working muscles, promote optimum hydration and jumpstart the recovery process.
Research shows that a strategic approach to sports nutrition can make you a better triathlete. How you hydrate and fuel can make the difference in being prepared for, energized during and rapidly recovering from the intense effort of triathlon training and competition. Make that difference with POWERBAR®!
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