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Did You Know?

Coffee was first discovered over 1000 years ago, and

currently approximately 75% of Americans drink coffee on a

regular basis. Despite the thousand years that have passed,

there is still mystery and controversy surrounding the biological

effects of coffee and it's active principal ingredient; caffeine.

Caffeine is the most widely used stimulant 'drug' in the world,

usually ingested in the form of coffee, tea, soft-drinks, and

chocolate. Caffeine is also used by triathletes and other

athletes as a performance aid. The purpose of this article is to

discuss the role of caffeine as an ergogenic (energy

generating) aid in endurance sports and to discuss the health

issues, such as cardio respiratory, related to caffeine use.


What happens when caffeine enters the body?


Caffeine is well absorbed from by the stomach and intestine,

and peak blood levels occur about 45 - 60 minutes after

ingestion. Once in the blood stream, caffeine causes a

number of responses in the body. Caffeine is well known for

it's stimulant effects on the brain, but there are a number of

other physiologic effects that occur. Blood pressure, pulse

rate, and stomach acid production are increased, fat stores

are broken down, and fatty acids are released into the blood

stream. These effects can last from a few hours to as long as

12, but within 4 days of regular use, the body develops

tolerance to many of the effects of caffeine.

For example, caffeine increases blood pressure and pulse rate in a first

time user, but a regular user will not experience any significant

alterations in comparison.


Caffeine and Health


In making a decision whether or not to use caffeine -- or any

other drug -- it is important to consider the potential adverse

effects it may have on your personal health. These can be separated into short term (i.e.

related to a single dose) and long term.

The short term affects of caffeine are much better understood than the long term

effects. Because caffeine increases the production of stomach acid it

may worsen ulcer symptoms or cause acid reflux

("heartburn"). Insomnia, poor sleep, and anxiety are well

described psychological side effects of caffeine use. Regular

evening use of caffeine may, over time, deprive the body of

proper sleep, resulting in lack of energy and fatigue.


Many studies have suggested a relationship between chronic

caffeine use and a number of diseases. Proving a cause-and effect,

however, has been difficult and most of these

suggested links remain inconclusive. Some of the difficulties

that arise in studying the long term health effects of caffeine

are due to problems in accounting for other lifestyle variables

(eg. smoking, alcohol consumption, exercise), differences in

genetic inheritance, form of caffeine intake (coffee, tea,

sodas), and the presence of other biologically active

substances in the beverage.


For example, one study looked at whether or not caffeine intake increased

the risk of heart disease. Over 45,000 people were evaluated and the data

indicated a slightly increased risk of death from heart disease

in individuals who had an average daily consumption of more

than 5 cups of *decaffeinated* coffee. Currently, there is no

evidence that caffeine causes cancer, stomach ulcers, high

blood pressure, or serious heart arrhythmia.


Caffeine Withdrawal


Abrupt discontinuation of caffeine in a regular user may trigger

caffeine withdrawal symptoms. The most common symptoms

are headache and fatigue. The headache may begin as soon

as 18 hours following the last dose of caffeine and may

worsen with exercise. It is not known why some people

experience caffeine withdrawal and others do not.


Caffeine and Athletic Performance


Despite considerable research in this area, the role of caffeine

as a performance enhancing drug is still controversial. Some

of the data are conflicting, which is in part due to how the

experimental studies were designed and what methods were

used. However, there is general agreement in a few areas:

Caffeine does not appear to benefit short term, high intensity

exercise (eg. sprinting).

Caffeine can enhance performance in endurance sports.

Glycogen is the principal fuel for muscles and exhaustion

occurs when it is depleted. A secondary fuel, which is much

more abundant, is fat. As long as there is still glycogen

available, working muscles can utilize fat. Caffeine mobilizes

fat stores and encourages working muscles to use fat as a

fuel. This delays the depletion of muscle glycogen and allows

for a prolongation of exercise. The critical time period in

glycogen sparing appears to occur during the first 15 minutes

of exercise, where caffeine has been shown to decrease

glycogen utilization by as much as 50%. Glycogen saved at

the beginning is thus available during the later stages of

exercise. Although the exact method by which caffeine does

this is still unclear, caffeine caused sparing in all of the human

studies where muscle glycogen levels were measured. The

effect on performance, which was observed in most

experimental studies, was that subjects were able to exercise

longer until exhaustion occurred.

In addition to the beneficial effects on muscle, caffeine may

alter the perception of how hard you are working. During

testing, athletes are asked to judge their effort, which is

referred to as the rating of perceived exertion (RPE). Some

studies have yielded significantly lower RPE's -- less fatigue --

when the athlete used caffeine. Other studies have not found

this effect. Obviously, the RPE is very subjective, and there

are many things that may influence it.


What about caffeine in Ironman races?


The exercise studies on caffeine involved endurance testing of

approximately 2 hours, so there is no specific information

related to ultra-endurance races. Pre-race caffeine may be

beneficial though, because the longer the race, the more

important fat is as a fuel. During the race, caffeinated soft

drinks are one of the choices at the aid stations in an Ironman race.

Whether this source of caffeine is useful or not remains unknown, but these

soft-drinks do supply the individual with the necessary carbohydrates. Because longer

races have a greater baseline risk of dehydration, nausea and

abdominal cramps, it is very important to consider the side

effects of caffeine (below).


Variable results and side effects.


Despite the known benefits of caffeine in endurance exercise,

individual results may vary greatly. Differences in metabolism,

diet, and frequency of caffeine use are some of the factors

that can determine how an individual will react to caffeine.

Additionally, some athletes may actually experience a

decrease in performance, usually due to side effects of

caffeine.

Although caffeine does not appear to significantly alter water

balance or body temperature during exercise, dehydration is a

potential concern because caffeine is a mild diuretic. Some

athletes may also experience abdominal cramps and diarrhea

related to the large intestine contractions caused by caffeine.

The combination of dehydration and cramping can have

particularly detrimental effects on performance.


What about drug testing?


The International Olympic Committee currently lists caffeine as

a restricted drug. Urinary levels up to a concentration of12

mg/liter are acceptable, representing casual use. Levels

above this are viewed as achieved through a deliberate

attempt at doping by the athlete. Approximately 1000mg of

caffeine (about 8 cups of coffee) would be required to exceed

the current IOC limit, but it is very important to note that

people can metabolize caffeine at very different rates.

Differences in metabolism, medications, and certain diseases

may significantly alter the rate in which caffeine is cleared from

the body. Some athletes have come close to flunking the drug

test after ingesting only 350mg. It is wise to consider this

before using caffeine as an ergogenic aid.

Recommendations for athletes

If you choose to use caffeine, then here are a few tips that

may help you maximize the benefits.

Ingest caffeine about 3 - 4 hours before the competition.

Although blood levels of caffeine peak much sooner, the

maximum caffeine effect on fat stores appears to occur

several hours after peak blood levels.


Consider decreasing or abstaining from caffeine for 3 - 4 days

prior to competition. This allows for tolerance to caffeine to

decrease and helps ensure a maximum effect of caffeine. Be

careful though, because some may experience caffeine

withdrawal.


Make sure that you have used caffeine extensively under a

variety of training conditions and are thoroughly familiar with

how your body reacts to this drug. Never try anything new on

race day.


Be prepared to accept the consequences if your urine test is

above the current cutoff.


Conclusion

In writing this article I am not suggesting that athletes use

caffeine nor am I supporting the use of performance

enhancing drugs. I am simply reviewing the use of caffeine as

an ergogenic aid as well as the known health consequences.

Athletes must individually decide whether or not it is

appropriate to use this drug -- both in competition and day-today.

All of the information for this article came from the current

medical literature. Those of you who take prescription

medications or who are under a physician's care should check

with your doctor about the relevance of caffeine to your health.


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