Caffeine in Athletics
By: Michelle Celie Drinkard
How does it affect cognitive function?
The
world’s most popular drug is legal, inexpensive, and believed to amplify
workouts. It supposedly motivates
athletes and helps them stay alert and focused while also boosting physical
endurance by twenty to fifty percent.
This stimulant is found naturally in sixty-three plants and is consumed
by eighty percent of Americans. This
white, bitter, crystalline substance is known as caffeine, and is commonly
consumed in efforts to enhance athletic ability (http://gopher1.bu.edu/COHIS/substance/caffeine/about.htm).
Caffeine
is a very popular stimulant among athletes because most believe that it
provides energy, increases alertness, and quickens reaction time. When in beverage form, caffeine reaches all
body tissues within five minutes of ingestion.
However, peak blood levels are reached in thirty minutes. Therefore, many cyclists consume a cup of
coffee half an hour before short races begin.
Others drink a bottle of coke diluted with water during the last half of
longer races (http://www.roble.net/marquis/caffeine). The use of caffeine is controversial in the
sports world, because it is a stimulant.
In fact, the UCI forbids drinking caffeine in large quantities prior to
competitions. But, why is there such a
desire amongst athletes to consume this drug?
Are its results really that effective?
To answer these questions one must investigate how caffeine works.
How does it affect the body?
The exact process by which it affects the body is unknown. It is suspected that caffeine affects the
nervous system by altering the perception of effort and exciting the neurons
responsible for contracting muscles. It
may also be accountable for causing more fat and less carbohydrates to be
burned. Another source suggests that
caffeine alters the levels of CNS neurotransmitters and metabolism of
circulating free fatty acids. The end
result is an increase in blood sugar for use as muscle fuel. Basically, it is believed that caffeine
raises the general metabolism of the user, which resultantly increases the
activity and raises the body’s temperature (wysiwyg://35/http://onhealth.com/ch1/indepth/item/item.34623_1_1.asp).
What
about endurance?
Various
studies have been conducted in attempts to connect the use of caffeine with
increased endurance levels. Graham and
Spriet (1995) conducted a double-blind test involving eight endurance
runners. Each participated in a control
test previous to the study in which they ran a prescribed distance, to the
point of exhaustion. All ate similar
meals and abstained for caffeinated substances previous to the trials. Over a four-week period, each runner
returned to the laboratory to run the prescribed distance while intravenously
being given varying doses of caffeine.
A blood and oxygen sample was collected every fifteen minutes during the
run in order to record the time span until physical exhaustion was
reached. The results confirmed that low
doses of caffeine caused a drastic increase in endurance levels, while not
altering the epinephrine (or adrenaline) levels. Also, large doses of caffeine caused great increases in plasma
epinephrine levels while only slightly altering the endurance levels. This test, therefore, supposes that small
doses of caffeine, when compared to placebo trials, are very beneficial in
raising endurance capabilities.
A
very similar test by Pasman (1995) was conducted in which nine advanced
cyclists were studied concerning their rate of time until exhaustion. Each came in on a weekly basis at the same
time and day of every week. The
cyclists were told to swallow a capsule that contained varying amounts of
caffeine, though neither the cyclists nor the administrator knew the amounts
the subjects received. After an hour of
rest, the cyclists were told to ride until exhaustion to measure endurance
levels. The results suggest that
endurance increased with the consumption of small amounts of caffeine, when
compared with placebo trials.
Surprisingly, no difference appeared between the varying amounts of
caffeine in each capsule.
With regard to short-term endurance,
caffeine appears to have conflicting effects.
During a prolonged handgripping contraction test, caffeine appeared to
improve muscular force production. A
review by Williams (1991) further supported this theory. Cyclists were asked to ride to
exhaustion. Then, they were injected
with caffeine during a twenty-minute resting period and once again subjected to
the cycling. Caffeine appeared to
improve each following test by 22%.
However, in a 100-yard swimming test, subjects did not appear to benefit
from ingesting various levels of caffeine when compared to the control
groups. This concludes that there are
no clear connections between the effects of caffeine on short-term muscular
endurance capabilities. In four similar
tests, contradicting evidence repeatedly appears.
The review of Dodd,
Herb, and Powers (1993) draws the connection between human and animal
receptiveness to caffeine. In animal
studies, large caffeine doses cause increased muscle contraction and what would
be enhanced physical performance in humans.
However, the amount of caffeine necessary to make the same improvements
in humans is not usually feasible and quite possibly toxic.
How does it affect
cognitive function?
To decipher whether caffeine is beneficial to athletic ability, one must also take into account its role on mental abilities. Hogervorst (1999) conducted a double blind study on fifteen triathletes. Each was subjected to visual and audible testing regarding Dutch vocabulary. A word would appear on a computer screen and be pronounced. At the end of fifteen minutes the athletes were asked to recall as many of the words, that they had just been taught, as was possible. Before each trial, caffeine or a placebo was ingested on a randomized basis. The results imply that caffeine causes increased cognitive function when compared to the control trials. This effect is desired amongst athletes as quick reasoning is crucial in many instances.
Ferrauti
(1997) reviewed the effects of caffeine in drink form on athletic
performance. Sixteen advanced tennis
players participated in the study; each was fed standardized meals and no
caffeine was consumed prior to testing.
Before and after each match blood and urine samples were collected with
the intent of measuring the free fatty acids present in the system. The results did not provide clear results
regarding caffeine’s effect on athletic ability. After consumption running speed was improved, though accuracy did
not differ.
Caffeine has many dangers involved in its consumption. It is believed to lead to pancreatic or
bladder cancer, elevate cholesterol levels, increase risk for heart disease and
heart attack, and temporarily raise blood pressure. More common side effects include nervousness, restlessness,
anxiety, irritability, and aggravated premenstrual cycles in women. Caffeine is also responsible for a greater
excretion of calcium in urine, which makes bones more brittle and can
eventually lead to osteoporosis (http://www.mayohealth.org/mayo/9707/htm/coffee.htm).
The Diuretic Effect
The
diuretic effect raises concerns with athletes concerned with long
distances. One would not want to lose a
tri-athalon because he/she had to stop to urinate. Tarnopolsky (1994) asserts that caffeine consumption does not
affect sweat loss or plasma volume, therefore proclaiming that caffeine would
not be detrimental to endurance athletes in way of urination or
heatstroke. The study involved five
athletes running in unpleasantly hot and humid conditions for an hour at a
time. Each ingested different amounts
of caffeine with varying trials.
In
a similar study, Wemple (1997) asserts that caffeine does not increase the loss
of bodily fluid during exercise. Six
athletes participated in a preliminary physical exertion test so that a control
would be set for each individual. In
following weeks all consumed foods similar to those that would be eaten prior
to any athletic competition and caffeine was restricted. On testing days each entered the lab and
ingested a randomized amount of caffeine on a double-blind basis. The subjects then waited in humidified rooms
for fifteen minutes before physical exertions were again tested, followed by
blood, urine, and sweat samples.
Although caffeine does increase urine flow in at rest individuals, it
had no effect on individuals engaged in exercise. This suggests that athletes should not be concerned with caffeine
causing a need to urinate any more than any other beverage.
Perhaps one of the most startling risks involved with caffeine is the risk of a raised blood pressure. Kaminsky (1998) shows the relationship between caffeine ingestion prior to physical activity and its effect on blood pressure. Eighteen men were chosen to take part in a study where all consumed varying levels of caffeinated beverages, with the chance of receiving a placebo. The drinks were administered on a double-blind basis. Following the consumption, the men were asked to remain at rest and at later trials to perform various degrees of physical exertion. The results prove that caffeine raises both diastolic and systolic blood pressure when at rest. Also, caffeine heightened the systolic blood pressure at every level of activity, whereas it only raised the diastolic blood pressure at the greatest level of exertion.
Another
severe effect of caffeine is the possibility of its delaying one’s conception
capabilities. Hatch and Bracken (1993)
chose 1909 women out of a beginning group of 4186 women on the basis of their
being married to their first husbands, over the age of eighteen, pregnant, and
having conceived while not on a form of birth control. This retrospective study divided the women
up into two groups determined by the amount of time it took them to conceive
after they stopped taking birth control.
These groups were asked various questions regarding their caffeine consumption
on a daily basis. The results did not
suggest a correlation between caffeine intake and infertility. However, when pared with smoking, caffeine
consumption resulted in delayed conception.
More things to consider
Caffeine
is classically addictive. Regular users
develop tolerance towards it and thus, require more to obtain the expected
effect. Withdrawal symptoms usually
include headache for several days and possible constipation (http://www.healthyideas.com/healing/herb/coffee.html). The United States Food and Drug
Administration and the American Medical Association profess the safety of
caffeine. However, both the Canadian
and the United States governments advise pregnant women to restrict their
caffeine intake. Pregnant women who
consume three cups of coffee a day have a greater chance of miscarriage than
those who do not (http://gopher1.bu.edu/COHIS/subsabse/caffeine/sympsign.htm). There is bitter dispute between caffeinated
product manufacturers and natural remedy advocates over the benefits and
consequences of caffeine. Manufacturers
appeal to the public, particularly athletes, on the professions of increased
alertness. Contrastingly, herbal
advocates point out the sometimes-drastic side effects of this popular
stimulant.
Conclusion
In conclusion, caffeine does appear to improve long-term physical endurance when ingested in various amount. However, no clear connection between caffeine consumption and short-term endurance has been drawn. The diuretic effects of caffeine do not appear to pose a problem to athletes, though caffeine at rest does cause increased urination. The risks involved with caffeine range from elevated blood pressure to delayed conception ability. These factors should be carefully considered before caffeine is embraced in one’s lifestyle.
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