Guest blogger and T1V runner Kelly Currier is a nutritionist who blogs at tidbitsofnutrition.wordpress.com. Check out her blog for some great tips!
This post is dedicated to all the endurance athletes out there. The majority of my posts will be directed toward the general population, and on nutrition topics that anyone can apply to their life for healthier eating. But I do take requests! This post was inspired by a friend that is a triathlete that is always looking for ways to get better. But, before you sign off on this post, you should know that an “endurance athlete” does not just categorize those that run marathons, compete in triathletes, or other freaks of nature that go above and beyond the daily recommendations for exercise. Endurance exercise is typically defined as the ability of a person to perform exercise that raises the heart rate to a training level and can be maintained for at least 10-15 minutes without stopping. If you jog, cycle, swim, or power walk, you are performing endurance exercise.
Caffeine has been shown to enhance endurance-type performance in people who do not regularly consume caffeinated products. Caffeine stimulates your central nervous system and is also a muscle relaxant. Although it is not fully understood WHY caffeine has positive effects on endurance performance, here are some of the better known theories:
1. Caffeine delays glycogen (carbohydrate or energy) breakdown. One study showed that the ingestion of caffeine increased the concentration of free fatty acids (FFAs) in the blood. The increased availability of FFAs enhances the use of fat as fuel in endurance-type, low-intensity activities. This can delay the breakdown of glycogen (a.k.a. carbohydrate) from your muscles to be used as fuel. And since glycogen is the rate-limiting factor in exercise (i.e. when you run out of glycogen, you cannot keep exercising), this can be a VERY beneficial effect. The two most important tasks that you must tend to during endurance exercise are staying hydrated and replenishing your glycogen stores. So, if caffeine can delay glycogen use, that is a major positive. And hey, who doesn’t want to burn a little extra fat?!
2. Caffeine may decrease your rate of perceived exertion (RPE). Because caffeine stimulates your brain, it makes you feel energized and possibly stimulates the brain into a lower level of fatigue. In other words, caffeine can make the work that you are doing seem less strenuous and therefore may encourage you to run faster, pedal harder, etc.without feeling as fatigued.
Even if you do not compete as an endurance athlete, you may still enjoy the benefits of consuming caffeine before exercise. Many people find that after consumption of a moderate amount of caffeine, they are able to exercise longer at a steady pace.
The next important question is “HOW MUCH caffeine should you consume to have a positive effect?” Too little caffeine is a waste. Too much caffeine can have detrimental effects such as insomnia, anxiety, diarrhea, and irritability. For those that consume caffeine regularly, it will take a larger dose to have an effect. If you are a regular caffeine consumer but are dedicated to improving your performance with the use of caffeine, you really should back off your caffeine consumption during non-training periods. If you are one of the 10% of American adults that does not regularly consume caffeine, then you have the greatest potential to enhance your performance with caffeine. The recommended dose of caffeine is 3-9 milligrams per kilogram of body weight. To get your weight in kilograms, divide your weight in pounds by 2.2. An 170 lb (77 kg) runner should consume 231-693 mg of caffeine. Research also shows that approximately 250 mg of caffeine appears to aid performance in long-endurance activity (greater than 90 minutes).
Caffeine Content of Widely Available Foods, Beverages, and Over-the-Counter Drugs
Regular drip coffee (16 oz) = 320-528 mg
Grande Starbucks coffee (16 oz) = 550 mg
Red Bull (8 oz) = 80 mg
Powerbar energy gel = 25-50 mg
Iced tea (12 oz) = 65-75 mg
Soda (12 oz) = 38-54 mg
Finally, WHEN is the best time to consume caffeine? Research shows that although it takes 45-60 minutes to reach the peak level of caffeine in the blood, it takes 3-4 hours to see the peak level of performance after consuming caffeine. It is important to consume caffeine before exercise rather than during because the critical time period for glycogen sparing occurs during the first 15 minutes of exercise. Thus, you save glycogen for the latter part of training/competition when you need it most. The best thing to do is just experiment during training. Everyone is different.
One last thing, never EVER use caffeine for the first time on race day. Always experiment a few times during training.
Disclaimer: consumption of caffeine can enhance urination and therefore lead to dehydration. Make sure that you are drinking plenty of fluids when supplementing with caffeine.