Caffeine, one of a group of substances called methylxanthanines, is probably the most commonly consumed drug in the world. An alkaloid that's derived from a variety of plants, it's inexpensive and readily available in pill form or in such common commodities as coffee, tea, cola, chocolate, cocoa and performance gels.
Have you had your meth fix today? You probably have, as about 80 percent of Americans consume caffeine on a daily basis. Like those millions you may depend on it to improve your mental alertness and augment your perceptions of well-being. Caffeine is much more than a cerebral pick-me-up, however. It's also an effective aid for enhancing exercise.
Over the past 20 years the scientific community has devoted vast resources to exploring the physiological effects of caffeine on exercise, and the results have clearly demonstrated that it can provide a variety of advantages. You can enhance fat use during exercise, and you can improve both aerobic (long-duration, low-to-moderate-intensity) and anaerobic (short-duration, high-intensity) exercise performance with caffeine supplementation. So, whether you're a weekend warrior, fitness buff or highly trained athlete, you can rejoice. One of the most functional exercise aids may be right under your nose.
Caffeine Burns Fat
If you're concerned about reducing your bodyfat percentage, caffeine can be your ally. Whether you're at rest or at play, caffeine will increase the level of free fatty acids in your blood.
The aerobic fat-burning advantages that you can get from caffeine supplementation are phenomenal. For example, a typical 170-pound person will burn approximately 800 calories per hour while running at a moderate pace, and about half of those calories will be burned due to fat oxidation. If that person uses a caffeine supplement, however, fat oxidation may be increased by as much as 50 percent, which translates into an additional 200 fat calories burned. Ultimately, then, the runner may expend 600 calories per hour through fat oxidation, while the breakdown of sugar would account for most of the remaining 200 calories.
Caffeine Enhances Performance
At present we don't fully understand the physiological effects of caffeine, but there's a consensus that it causes at least three biological responses that improve exercise performance.
1) The fat-mobilizing nature of caffeine not only augments your ability to burn fat, but it also improves your total aerobic capacity. During aerobic activities your body burns an abundant store of fat and a limited store of glycogen, or sugar. Once the glycogen in the active muscles has been used up, performance is greatly reduced. By taking in caffeine, you can increase the level of free fatty acids in your blood, which facilitates what's known as a glycogen-sparing effect. Your body uses more fat as fuel, and the rate of glycogen depletion decreases, which delays the onset of fatigue and allows you to exercise longer.
2) Caffeine improves muscular function by facilitating muscle contraction. Before contraction can take place, calciumions must be released inside your muscle cells. Caffeine increases the cells' sensitivity and increases the availability of the calcium. A smaller stimulus is then required to cause greater twitch tension, which enables your muscles to contract with less effort. In addition, there's research showing that caffeine increases the contraction force of the diaphragm, which suggests that it will enable you to breathe with greater ease during exercise. That should be of particular interest to people who have breathing disorders and athletes who compete at extreme altitudes.
3) Caffeine affects the central nervous system by masking the perception of fatigue. Although it's difficult to assess objectively the effect of caffeine on the central nervous system, it's clear that it can cross the blood/brain barrier. Using the semiquantifying Borg Rating of Perceived Exertion scale, athletes have consistently reported a reduced perception of fatigue. Test subjects tend to choose and maintain a higher exercise intensity yet they perceive the intensity to be lower. So, if you reach an exercise plateau in your training or "hit the wall," as the saying goes, caffeine's fatigue-masking qualities may help you exceed your present limits.
Several studies have focused on caffeine's effect on aerobic performance, but the one that's perhaps the most frequently cited is the 1978 Ball State study mentioned above. Using a cycle ergometer, subjects were able to pedal 20 percent longer after drinking coffee that contained five milligrams of caffeine per kilogram of their bodyweight. Since then, numerous research groups have confirmed that the substance enhances aerobic effects, and athletes have consistently been able to sustain a higher level of power and exercise for as much as 51 percent longer, on average. In particular, one test subject was able to increase total aerobic capacity by a staggering 156 percent!
Research on caffeine's effects on anaerobic capacity is less conclusive, but there are indications that muscular endurance and anaerobic power can be improved. In a 2001 study subjects consumed 250 milligrams of caffeine and exhibited a 7 percent increase in power during a series of cycle ergometer sprints. In another study conducted in association with the Human Performance Laboratory at the University of Calgary, researchers assessed the effect of six milligrams per kilogram of bodyweight on performances during a high-intensity 1,500-meter swim. That's particularly significant in a race, since mere fractions of seconds may separate the winner from the losers.
It appears that caffeine is infinitely versatile. Whether you run, cycle swim or climb stairs; whether you play hockey, basketball, soccer or rugby, it can greatly improve your exercise performance and provide a competitive edge. It can also enhance such components of resistance training as muscular endurance and anaerobic power. In fact, muscular strength is the only aspect of exercise on which caffeine hasn't been shown to provide a performance benefit; however, there is ongoing research in the field.
Guidelines for Caffeine Supplementation
Using caffeine is one of the most functional supplement strategies available. It's inexpensive, easily acquired, easy to use and extremely effective. Here are five tips that will help you maximize the benefits.
1) Have a Strategy for Your Caffeine Intake
There's speculation that the effects of caffeine supplementation may be blunted in people who regularly consume caffeine, but there's no definitive proof. In fact, several studies have shown that both heavy users (more than six cups of coffee per day, about 660 milligrams of caffeine) and light users (fewer than two cups of coffee per day, about 220 milligrams) exhibited similar performance results. Still, it would be prudent to have a strategy for your caffeine intake.
• lf you typically drink several cups of coffee a day, try to restrict your coffee on training days, then drink some before you exercise.
• lf you're a serious athlete, try to restrict your caffeine or stop taking it altogether for approximately 72 hours before a competition. Theoretically, that will maximize its effectiveness as a precompetition boost.
• lf you're a heavy caffeine user and you plan to abstain before a competition, carry out a trial run to see how you respond to caffeine withdrawal.
2) Choose Your Supplement Wisely
It's important to choose a reliable source. Here are the doses you get with various available sources and a rundown of the effectiveness of each.
Milligrams of Caffeine
|Caffeine pills (pure caffeine)||
100 - 200
|Espresso, 1-ounce shot||
|Coffee, 8 ounces||
115 - 174
80 - 135
65 - 100
|Tea, 8 ounces||
40 - 75
|Iced tea, 112 ounces||
|Cola, 12 ounces||
30 - 60
Caffeine pills are functional and reliable. By using pure caffeine you simplify digestion and get the full effect. You also make it easy to get the precise dose for your bodyweight.
There's new evidence that caffeinated coffee may not be as dependable as pure caffeine. In a recent study researchers suggested that additional chemical compounds found in coffee beans may moderate the exercise-enhancing characteristics of caffeine. That's only one study, however, in contrast to others that have demonstrated exercises advantages from using coffee as an ergogenic aid. So your best course is to rely on your own experience and personally compare coffee to pure caffeine.
If you want to use coffee as your caffeine supplement, espresso is the most practical choice. Before your workout you can visit your favorite coffee establishment and order the appropriate number of espresso shots in a plethora of flavorful variations. Note that many espresso drinks have a high fat content. A typical mocha, made with whole milk and whipped cream, contains approximately 20 times the fat of a skim-milk latte, so try to restrict yourself to a lean variation. It will contain much less fat and fewer calories and will be digested more readily than any of the more decadent choices.
The primary advantage of homemade coffee and tea is convenience. You can also manipulate the strength of the brew, but the resulting caffeine concentration won't be
accurate. Iced teas and colas aren't effective sources of supplemental caffeine, as they contain mostly sugar and only small amounts of caffeine. As such they can actually be detrimental to exercise performance.
• In order to attain ideal caffeine levels, you may need to drink several servings, which may cause gastric irritation.
• Preexercise carbohydrate feedings tend to cause a depressed level of plasma free fatty acids, which may limit your aerobic capacity.
• Iced teas and colas typically contain large amounts of simple sugar, which causes a state of hypoglycemia, or low blood sugar. Consequently, when you begin to exercise, intramuscular sugar is used at a much higher rate, which typically results in a rapid onset of fatigue.
• Hypoglycemia is also associated with a dramatic increase in insulin, which inhibits the mobilization and use of fat as a fuel.
Performance gels are compact supplement packages that are designed to enhance athletic endurance. At about 100 calories they typically contain special blends of simple and complex carbohydrates, amino acids, vitamins, minerals, electrolytes and therapeutic herbs. Some also contain small amounts of kola nut, a natural source of caffeine, but it's not a functional source of supplementation. In fact, if used incorrectly, performance gels can be quite ineffectual.
The bottom line is that preexercise carbohydrate feedings of any sort will compromise the ergogenic effects of caffeine. Such limitations can be partially offset if you continue taking in sugar at regular intervals during your training, approximately every 20 minutes. A constant flow of carbohydrates will spare muscle glycogen, neutralize the effects of hypoglycemia and augment your muscles' ability to use glucose. The downside is that it will also limit your ability to use fat as a fuel. Moreover, unless you're engaged in an activity that lasts longer than 60 minutes, you probably won't deplete your glycogen stores, in which case carbohydrate feedings would be unnecessary.
3) Start Out Small
In a 2001 study researchers assessed the effectiveness of various doses of caffeine on exercise performance. The results showed that a dose as small as three milligrams per kilogram of bodyweight increased the level of plasma free fatty acids by 58 percent and enabled subjects to exercise 22 percent longer. A moderate quantity (4.4 milligrams per kilogram) proved to be optimal for enhancing aerobic capacity; while amounts greater than six milligrams per kilogram led to a significant decrease in performance. The above data may not be definitive, however. In another study that was published in the same journal, subjects demonstrated a 51 percent increase in aerobic capacity after taking in nine milligrams of caffeine per kilogram of bodyweight.
So, how much caffeine should you take? Consider the following points. To convert kilograms to pounds, multiply your weight by .4536.
• Three milligrams per kilogram is enough to significantly enhance fat oxidation and improve aerobic performance.
• Three milligrams per kilogram is enough to greatly improve anaerobic power and muscular endurance.
• 4.4 milligrams per kilogram seems to be the ideal amount of caffeine for enhancing aerobic capacity.
• Of the studies considered in this article, 5.7 milligrams per kilogram is the average amount of caffeine used by researchers.
• A nine-milligrams-per-kilogram dose may or may not provide a performance benefit.
• Nine milligrams per kilogram has been associated with nausea, disorientation and diarrhea.
• An amount greater than nine milligrams per kilogram may be toxic.
If you aren't a competitive athlete, you may want to experiment to find your ideal dose. Don't assume that a particular amount will work as well for you as it does for another athlete.
4) Allow 60 Minute for Absorption Before You Train
The peak plasma level of caffeine occurs approximately 60 minutes after consumption. The researchers in the Ball State study noted up to a 100 percent increase in plasma free fatty acids after only 60 minutes, and allowing 60 minutes for digestion is common among research groups. Therefore, 60 minutes seems to be a practical choice.
5) Hydrate and Evacuate
To ensure optimal plasma volume and a functional level of perspiration, it's important to hydrate your body prior to exercise. Theoretically, that's even more crucial if you use caffeine because caffeine is a diuretic; that is, it causes fluid loss. In a 1995 Canadian study, however, athletes exhibited no abnormal fluid loss after consuming 7.5 milligrams per kilogram of bodyweight and running for 60 minutes at about 89 percent of their maximum heart rate. Still, you don't want to overlook the hydration factor. So drink 13 to 20 ounces of cold water 20 to 30 minutes before prolonged exercise and evacuate as needed.