Recovery from long distance: how about a bowl of cereal?

Over the past couple of decades, much work has come out of the Exercise Physiology and Metabolism Lab at the University of Texas at Austin. Much of this work has demonstrated the positive effects of combining protein and carbohydrate intake both during and following a long bout of exercise (a few hours, give or take). The merits of carbohydrate have been well known by athletes and scientists alike but its only been recently that the significant contributions of dietary protein for endurance performance and recovery have been investigated in well controlled studies.

The group at UT Austin has a new study out in the Journal of the International Society of Sports Nutrition (Kammer et al). They attempted to make this investigation more practical to athletes by testing the effects of eating a bowl of cereal with nonfat milk against a popular carbohydrate sport drink. Twelve cyclists and triathletes (8 men and 4 women) performed two 2-hr bouts of cycling at a moderately high intensity on separate days. Following the ride, they were provided either 40 oz of sport drink containing 78.5 grams of carbohydrate or a bowl of whole grain cereal and 1/3 liter of nonfat milk containing 59 grams of carbohydrate and 7.3 grams of protein. They were also give 3/4 liter of water on the cereal day to match the fluid amount of the sport drink.

The investigators measured muscle glycogen levels (biopsy needle method) immediately following exercise and again 1 hr later. They also measured blood glucose, insulin and lactate levels. Muscle tissue was also analyzed for proteins that are involved with glycogen and protein resynthesis through the effects of insulin.

What they found:

• Insulin levels were higher during the 60-min recovery period during the cereal trial compare to the carbohydrate drink trial.
• Glucose levels were similar between trials during the 1-hr recovery.
• Glycogen resynthesis was similar between trials during the 1-hr recovery.
• Muscle tissue proteins were similar between trials during the 1-hr recovery.

What does this mean for you? If you prefer cereal and milk following a long workout or race, go ahead and eat as long as you rehydrate as well. Cereal and milk are just as effective for glycogen replenishment as a sport drink. Another way to look at this is that the protein from the cereal and milk provides no additional benefits to glycogen resynthesis as long as the amount of carbohydrates is adequate. Practically speaking, it comes down to personal preference once again. As long as you consume adequate carbohydrate and protein following a long bout of exercise, you'll do just fine regardless of the source.

The recommended amount of carbohydrate or carbohydrate + protein following a glycogen depleting bout of exercise is 1.2 grams for every kilogram of body weight per hour. For a 150 lb person, that's about 80 grams of carbohydrate or 55 grams of carbohydrate + 25 grams of protein. For a 180 lb person, thats about 100 grams of carbohydrate or 65 grams carbohydrate + 35 grams protein.

For more information on protein-enhanced supplements go to my website: http://cmierphotoandfitness.net/protein.html

Reference: Kammer et al. Cereal and nonfat milk support muscle recovery following exercise. J. Inter. Soc. Sports Nutrition, 2009.

Quercetin: a magic bullet for ultradistance athletes?

Aerobic exercise causes oxidative stress. It's a natural occurence that results from by-products produced from oxidative processes that are necessary for aerobic metabolism. These by-products, sometimes referred to as "free radicals" or "reactive oxygen species" (ROS) are also created from the inflammatory responses to muscle injury resulting from prolonged, repetitive muscle activity. It's most evident in long distance runners whose muscles are activated eccentrically (producing force while being stretched, during the stepping phase of running).

The problem with ROS is that they are believed to instigate muscle injury and reduce immune function making some athletes more susceptible to infection. In fact, increased incidence of upper respiratory tract infection occurs in athletes during heavy training and competition. Those athletes who engage in prolonged intense exercise will experience a significant amount of oxidative stress, which can lead to muscle injury, increased fatigue and increased susceptibility to infection.

Bring on the antioxidants. Antioxidants, natural chemicals in the body, fight the ROS and do it quite effectively. There are many types of antioxidants but one type in particular is the group known as flavonols. Flavonols are thought to be anti-inflammatory, cardioprotective, anticarcinogenic and antioxidative. One flavonol getting more attention in endurance exercise research is quercetin, naturally found in foods such as onions, berries, red wine, broccoli, apples and tea. It's getting more attention as a supplement, often sold in a blend containing vitamin C (another antioxidant that enhances quercetins effects) and niacin (for it's blood flow enhancing capabilities). It is believe that quercetin supplementation can increase the body's antioxidant power and possibly reduce those negative effects from ROS. In fact, one group of investigators observed reduced upper respiratory tract infection among athletes consuming the supplement.

To test quercetin's effects on blood oxidative capacity in response to ultramarathon competition, Quindry et al from Appalachian State University in North Carolina tested several athletes competing in the 160-km Western States Endurance Race. Sixty three male and female athletes were recruited and placed into either a quercetin group or a placebo group. The study was a randomized and double-blinded. For three weeks, athletes in the treatment group consumed 1000 mg quercetin, 1000 mg vitamin C and 80 mg niacin daily. Blood was drawn prior to the race and during the first half hour following the race. The investigators tested the athletes for plasma antioxidant capacity, the first indication that quercetin is indeed decreassing exercise-induced oxidative stress.

What they found:

• Quercetin levels were 6.6-fold higher in the quercetin group compared to the placebo group
• Quercetin levels decreased significantly during the race in both groups
• Quercetin supplementation did not affect plasma antioxidant capacity
• Quercetin supplementation did not alter oxidative damage

Conclusion: this study did not find a protective effect from quercetin supplementation during ultramarathon running. So, is it worth the money to buy the supplements? Maybe, because some studies have noted positive effects.

Final word: Instead of supplements, why not get your quercetin from vegetables and fruits? A well balanced diet containing several daily servings of fruits and vegetables will more likely provide you all the antioxidant power (in addition to several other benefits) you require as an endurance athlete.

Reference: Quindry et al. Oral quercetin supplementation and blood oxidative capacity in response to ultramarathon competition. Int. J. Sport Nutr. Exerc. Metab. 18, 2008.

Want to improve performance? Rinse your mouth with Gatorade

Well known to endurance athletes are the benefits of carbohydrate during exercise lasting more than an hour. Ingesting the appropriate amount (the recommended amount is 40-60 g/hr, which is equivalent to 2/3-1 liter of Gatorade per hour) improves endurance performance. The effect of eating carbohydrate is to maintain optimal rates of carbohydrate use in the muscle, with or without sparing the glycogen stores. This becomes particularly important during the latter stages of endurance exercise when liver glycogen stores are too low to maintain blood glucose and avoiding hypoglycemia becomes difficult.

During exercise lasting 1 hour or less, the evidence for rationalizing carbohydrate ingestion is less clear. Some studies indicate that ingesting carbohydrate during this short period does indeed improve performance, while others have not observed this. Because of the lack of consensus, carbohydrate ingestion during periods of exercise lasting less than 1 hour has never been vigorously recommended.

Interestingly enough, there is some evidence that simply mouth rinsing with a carbohydrate drink improves performance, at least in cyclists. When given a carbohydrate drink just as a mouth rinse, some athletes began to feel better and were able to pick up the pace without having swallowed the carbohydrate. These results suggest that the brain may be monitoring the carbohydrate stores in the body. If the brain recognizes the carbohydrate in the mouth, it may be receiving signals that indicates an incoming energy source. In anticipation of its energy source, the brain may alter its response to exercise, resulting in a selected faster pace.

To further investigate this effect, Rollo and colleagues from Loughborough University in the UK tested carbohydrate mouth rinsing on runners during a 30-min treadmill run. These investigators did something alittle different from traditional performance studies. One way to test performance in the laboratory is to quantify power output or distance during a set amount of time and allow the athlete to adjust the pace accordingly. This is relatively easy to do with cyclists because the athlete simply has to increase or decrease his or her pedal rate to affect power output. But for runners on a treadmill, changing the running pace is less spontaneous and requires manual adjustment of the treadmill speed. To overcome this limitation, these investigators used an automated treadmill where the speed of the treadmill was automatically changed when the runner simply moved to the front or the back of the belt.

Ten endurance trained male runners each ran twice for 30 minutes, once with a placebo and once with a carbohydrate solution mouth rinse provided. The athletes were asked to run at a hard pace and were free to adjust the intensity at any time during the run. The mouth rinse was administered every 5 minutes in an amount of 25 milliliters (5 teaspoons). This study was a double blind (no one knew if the athlete was getting the placebo or carbohydrate solution until after the study was completed) and randomized (the order of the trials ) study.

The investigators found that the carbohydrate mouth rinse did:

• not affect heart rate or sweat rate response
• not affect rating of perceived activation
• improve feelings of "good" at the beginning of exercise, but not after that
• increase pace during the first 5 min resulting in overall improved performance (greater distance covered during the run)

From these results, it appears that simply rinsing your mouth with a carbohydrate solution has some positive effect on performance. The actual improvement in distance was approximately 1/10th of a mile (4.1 vs 4.0), on average. That's an increase in average running pace from 8.0 to 8.2 mph, certainly enough to give someone an advantage during a race.

Why did the benefits only occur at the beginning of exercise? Maybe the brain is too smart to be fooled more than once. If that is the case, the strategy of mouth rinsing may be beneficial only during short duration exercise (less than 1 hour). At least for runners who are prone to GI discomfort during races, a mouth rinse may be an alternative to not drinking anything, at least during 5k or 10k races. Anything longer than that, you are better off swallowing that carbohydrate solution.

Reference: Rollo et al. The influence of carbohydrate mouth rinse on self-selected speeds during a 30-min treadmill run. Int. J. Sport Nutr. Exerc. Metab. 18, 2008.