Post-Workout Caffeine Consumption (and Other Recovery Tips)
By Monique Ryan
Triathletes are very familiar with the many performance benefits of caffeine. You may indulge in a caffeine-laden early morning wake-up call for a pre-dawn training session, while long-distance competitors often find cola to be a welcome sight on the run portion of the race. With all the hundreds of studies on caffeine consumption before and during exercise and it positive performance effects, there has been no study on caffeine consumption after exercise- until now. Published in the Journal of Applied Physiology,a group of researchers in Australia studied the effects of co-ingestion of caffeine and carbohydrate after hard training on muscle glycogen stores (Journal of Applied Physiology, May 2008).
“Endurance athletes often have to replenish muscle glycogen stores rapidly between training sessions, and consequently there has been a lot of research on recovery nutrition to see how we can boost muscle glycogen stores,” said research John Hawley of the RMIT University in Bundoora, Australia. Hawley proposed that since caffeine consumed during exercise and before exercise increase the availability of glucose, the same could be true when caffeine is consumed after exercise-induced glycogen depletion. In contrast, caffeine consumed at rest in untrained persons does not have the same effect.
Researchers decided to test their theory using highly trained subjects. Cyclists and triathletes who were cycling 12 to 15 hours per week completed a ride to exhaustion the night before the experimental trial. They consumed a low carbohydrate meal that evening, and again completed a short ride to exhaustion the next morning to ensure that muscle glycogen stores were extremely depleted. During four hours of recovery, subjects were provided with 4 g carbohydrate per kilogram of body weight from sports bars, gels and carbohydrate-containing sports drinks. During recovery from the other trial, caffeine was added to the sports drink, providing 8 mg per kilogram of body weight over the four hour period.
Researchers measured and compared parameters between the two trials. “With the ingestion of both caffeine and carbohydrate, the overall amount of glycogen stored in the muscle for the four hour period was 60-percent higher than with carbohydrate alone,” said Hawley. “There is absolutely no question that this additional muscle glycogen would improve performance.” Blood glucose and blood insulin levels were also higher with the caffeine and carbohydrate test dose, and glucose transport into the muscle may also have been enhanced with the caffeine. “There was a more available pool of glucose and the caffeine may have tricked the glucose into entering the cell,” said Hawley. “Essentially it put more gas or petrol back in the engine.”
Be aware that this is only one study and it used a very high dose of caffeine for research purposes. When testing a new idea or theory, researchers often use a large amount of a substance to first see if there is an effect. “For an athlete weighing 70-kilograms, this would be about 560 milligrams of caffeine,” said Hawley. “The dose we used is too high for athletes to use, and we now need to go back and complete a dose-response study.” In contrast, a serving of cola may provide 60 milligrams of caffeine, and 8 ounces of brewed coffee has 100 milligrams. “Bottom line is that we have to do a dose-response to see if our initial findings have some practical application,” said Hawley.
So while this study provides the first evidence that caffeine co-ingested with carbohydrate after a bout of glycogen depleting exercise, this caffeine dose could also result in a number of side effects for triathletes, such as insomnia, jitteriness, and GI upset. It is important for triathletes to appreciate their own personal tolerances to caffeine and not try anything new on race day.
Recovery Nutrition Primer
Post-exercise recovery nutrition jump starts the recovery process at an accelerated rate after endurance training. Recovery nutrition is especially important when there is less than eight hours between training sessions. Your goals are to replenish fuel stores, rehydrate, and facilitate muscle repair and recovery. Stay on top of your recovery nutrition and have appropriate foods, drinks, and supplements available.
- To restore fluid balance, drink fluids. If you are moderately to severely dehydrated when training is complete, you will have an increased risk of gastrointestinal upset that may limit your recovery food and fluid choices. Make hydration an immediate priority and start slowly.
- Monitor changes in body weight from the exercise session to evaluate hydration needs. After training, fluid losses will continue via sweating and urine losses, so drink adequately to compensate for these losses as well. Typically for every pound lost you should consume 24 ounces of fluid.
- When you are very dehydrated, fluids that also provide sodium can help to maximize fluid retention and minimize urine losses by replacing the sodium lost in sweat.
- Flavored and cool fluids should enhance fluid intake, though ice-cold fluids may be difficult to consume right after training.
- The diuretic effect of caffeine containing fluids has been overstated in habitual caffeine users, so some caffeine containing fluids are fine. Just drink enough volume to rehydrate properly.
- A less than optimal balance of fluid and sodium intake after exercise can result in large amounts of dilute urine during the recovery period. Don’t be fooled that you are adequately hydrated.
- Consume food and fluids that provide 1g of carbohydrate per kilogram of body weight immediately after training. Repeat this amount in one hour and incorporate these guidelines into subsequent meals and snacks.
- Your total carbohydrate requirements for the day are determined by the intensity and duration of your training.
- Compact forms of carbohydrate such as concentrated carbohydrate drinks, liquid meal supplements, smoothies, and energy bars are convenient on days that your total carbohydrate and energy needs are high, and followed by another demanding training day.
- Lower glycemic carbohydrates such as lentils and dried beans should not be the primary source of carbohydrate in recovery meals and snacks as they provide slower recovery.
- Higher glycemic carbohydrates for speedy recovery include cereals, breads and bagels, jams, and most recovery sports nutrition supplements.
- Consuming protein with recovery snacks can enhance the synthesis of protein tissue and contribute to the total protein intake required for your training.
- Intake of 10 to 20 g of high quality protein is the recommended amount. Protein can be included in recovery products and this amount is easily reached with balanced meals and snacks.
- An example of a recovery carbohydrate and protein food combination is cereal with milk and fruit.
- Don’t consume protein as the expense of carbohydrate choices. If training lasted more than four hours, wait to consume ample amounts of healthy fats in meals and snacks following the first two recovery feedings.