CAFFEINE - Physical Effects:

 -------------------------------- Page 1 of 21 --------------------------------
                               Table of Contents
1.  What are the short term effects of caffeine on the body?................2
2.  How long does it take to feel caffeine's effects?.......................4
3.  Why do I need my morning caffeine fix in order to function?.............6
4.  What are the symptoms of caffeine overdose?.............................8
5.  How can I decrease caffeine's negative effects?.........................9
6.  How does caffeine affect sleep?........................................11
7.  What are the effects of mixing caffeine and alcohol?...................12
8.  Are any health problems aggravated by caffeine?........................14
9.  Is it dangerous for pregnant women to drink coffee?....................16
10. Has coffee drinking been linked to heart disease?......................19
11. Is it true that coffee drinking can cause cancer?......................21





 -------------------------------- Page 2 of 21 --------------------------------
           What are the short term effects of caffeine on the body?

The physiological effects of caffeine can begin as early as 15-45 minutes after
ingestion.  Its maximum central nervous system effects are  reached in about
30-60 minutes. Caffeine increases heartbeat, respiration, basal metabolic rate,
and the production of stomach acid and urine; and it relaxes smooth muscles,
notably the bronchial muscle.   All of these changes vary considerably among
people and may depend upon the individual's sensitivity to this drug, his/her
metabolism, or upon whether the consumer habitually uses or rarely uses
caffeine.  How long caffeine's effects last is influenced by the person's
hormonal status, whether he/she smokes or takes medications, or has a disease
that impairs liver functioning.





 -------------------------------- Page 3 of 21 --------------------------------
What are the short term effects of caffeine on the body?

Subjectively, people report that caffeine gives them a "lift."  They feel less
drowsy, less fatigued, more capable of rapid and sustained intellectual effort.
They also report improved performance of some manual tasks such as driving.
However, caffeine may restore only those abilities or feelings  the person had
before fatigue or boredom set in. Studies have also shown that caffeine
decreases reaction time to both visual and auditory stimuli; it does not
significantly alter numerical reasoning (arithmetic skills) or short-term
memory; and it can diminish performance of manual tasks that involve delicate
muscular coordination and accurate timing.

When caffeine is taken in high doses it can cause many unwanted side effects.
To learn more about these, please read  "What are the symptoms of caffeine
overdose?"


 -------------------------------- Page 4 of 21 --------------------------------
               How long does it take to feel caffeine's effects?

Caffeine is rapidly absorbed through the stomach and small intestine into the
bloodstream, where it takes about 15-45 minutes to reach peak levels.  The
level of caffeine in the blood reaching the brain determines the potency of its
effects on the body.  Usually the central nervous system is maximally
stimulated within 30-60 minutes.  Caffeine is metabolized by the liver and
eventually its metabolites are excreted in urine, although caffeine can also be
secreted in saliva, semen, and breast milk.








 -------------------------------- Page 5 of 21 --------------------------------
How long does it take to feel caffeine's effects?

Caffeine will continue to have an effect on the body as long as it remains in
the blood.  The time required for the body to eliminate one-half of the total
amount of caffeine consumed (or caffeine's half-life) varies from several hours
to several days, but for the average non-smoking adult it is about 5-7 hours.
Several factors can lengthen caffeine's half-life, such as  some medications,
liver diseases, pregnancy, and the level of enzymes in the liver needed for
caffeine metabolism.  The half-life of caffeine in a pregnant women is 18-20
hours;  the half-life in women taking oral contraceptives is up to 13 hours.
Other factors, such smoking and age can shorten caffeine's half-life.   For
example, in children and smokers the half-life averages about 3 hours.





 -------------------------------- Page 6 of 21 --------------------------------
          Why do I need my morning caffeine fix in order to function?

Caffeine stimulates the central nervous system, temporarily increasing heart
rate, respiration rate, and metabolism.  This overall effect is usually
experienced as a "lift":  the user feels awake and capable of performing well,
both intellectually and physically.  It's not surprising that many people seek
this boost in the morning.

Even at moderate doses, it is clear that people develop a certain degree of
tolerance to caffeine, which means they need increasing doses to feel the same
"lift."  This is a sign that they are adapting to the drug's presence, and
chances are they will experience withdrawal symptoms if the caffeine is
discontinued. The most common caffeine withdrawal symptom is a throbbing
headache, usually occurring within 18-24 hours after the last dose of caffeine.
Other symptoms may include drowsiness, lethargy, yawning, irritability,
nervousness, depression, and nausea.

 -------------------------------- Page 7 of 21 --------------------------------
Why do I need my morning caffeine fix in order to function?

If you think that you "need" caffeine in order to function, try going without
for a day or two and see what happens.  The "need" might be a psychological
one, in which case a caffeine-free beverage could be substituted.  If you are
physically addicted, you'll need to endure the withdrawal symptoms for several
days while consuming caffeine-free substitutes.  For some helpful hints, please
refer to "Ten Tips for Breaking the Caffeine Habit," in the section, "Tips for
Breaking the Caffeine Habit."  More importantly, take a look at your lifestyle.
If you're chronically tired, try to sleep more each night, eat healthier foods,
and exercise regularly.  Who knows, the problem may not be the caffeine after
all!





 -------------------------------- Page 8 of 21 --------------------------------
                  What are the symptoms of caffeine overdose?

Caffeine stimulates the central nervous system and can produce a variety of
effects elsewhere in the body.  The symptoms of a caffeine overdose
("caffeinism") will vary, according to individual differences and the amount
consumed.  Doses ranging from 250 to 750 mg (2 to 7 cups of coffee or tablets
of NoDoz) can produce restlessness, nausea, headache, tense muscles, sleep
disturbances, and irregular heart beats.  Doses of over 750 mg (7 cups of
coffee) can produce a reaction similar to an anxiety attack, including
delirium, ringing ears, and light flashes.  These amounts of caffeine may come
from a single dose or from multiple doses at short intervals.  Besides
caffeine's effects, the essential oils of coffee may cause gastrointestinal
irritation and diarrhea, and the high tannin content of tea can result in
constipation.



 -------------------------------- Page 9 of 21 --------------------------------
                How can I decrease caffeine's negative effects?

1.  Dilute coffee or tea with milk, and drink low fat milk after a meal, to
     help coat the stomach and prevent gastric irritation.
2.  Drink brewed coffee at about one-half strength, or mix in some
     decaffeinated coffee before brewing.
3.  Be alert for the side effects of an overdose (which occur at different
     doses in different people), and stop drinking when you experience one.
     For more information read "What are the symptoms of caffeine overdose?" in
     this section.  Remember next time to drink less.
4.  Remember that caffeine is contained in many over-the-counter and
     prescription medications, and soda which can cause stimulation and add to
     your total caffeine intake.




-------------------------------- Page 10 of 21 --------------------------------
How can I decrease caffeine's negative effects?

5.  Carefully follow the directions on the labels for NoDoz and other caffeine-
     containing over-the-counter medications.  Do not exceed the recommended
     dosage.
6.  If caffeine causes you problems, consider gradually switching to
     decaffeinated coffee or alternative beverages see "What are some
     alternative beverages?,"in the section, "Tips for Breaking the Caffeine
     Habit" for several appealing options.
     (Adapted from ALCOHOL AND OTHER DRUGS:  SELF RESPONSIBILITY, Engs, 1987,
     p. 223).






-------------------------------- Page 11 of 21 --------------------------------
                        How does caffeine affect sleep?

Studies of the effect of caffeine on sleep have shown that one strong cup of
coffee, drunk 30-60 minutes before going to sleep, can cause restlessness and
difficulty falling asleep, increased body movements, a tendency to be awakened
more readily by sudden noises, and a decreased quality of sleep.

The wide variation in caffeine's effects on sleep may be related to whether the
person is a habitual, heavy user or a non-user of caffeine.  Non-users report
greater difficulty with sleep after consuming caffeine.  Heavy users may also
experience sleep disturbances; however, their increased tolerance to the
effects of caffeine affects their perceptions of disturbed sleep.  Often they
sleep for shorter periods of time, but have grown accustomed to this pattern.

If you use caffeine and are having trouble sleeping, you may want to try
cutting back on your total daily intake or avoid consumption 5-7 hours before
you plan on sleeping, to allow time for the caffeine to be metabolized.
-------------------------------- Page 12 of 21 --------------------------------
             What are the effects of mixing caffeine and alcohol?

Alcohol and caffeine have opposite effects on the central nervous system (CNS):
alcohol is a CNS depressant, while caffeine is a CNS stimulant.  But, giving
caffeine to someone who is drunk will NOT help the person to sober up.
Caffeine and other stimulants may make the person feel more alert, but will not
lower the person's blood alcohol content (BAC) which determines the level of
impairment.  These stimulants do not help the intoxicated person gain control
over coordination or psychomotor activity.  In fact, caffeine can make the
drunk driver even more dangerous.  By increasing alertness, drivers believe
that they can do things they are not capable of due to their blood alcohol
content.   The fact is, only time (roughly 1 hour per drink consumed) will
sober a person up once he or she has had one too many.




-------------------------------- Page 13 of 21 --------------------------------
What are the effects of mixing caffeine and alcohol?

People with heart problems should be especially cautious about mixing caffeine
and alcohol.  Each drug acts to increase heart rate; taken together, the effect
is greater than either one taken alone.  Cardiac arrythmias (irregular heart
beats) can result, which are especially dangerous for those with damaged or
weak hearts.










-------------------------------- Page 14 of 21 --------------------------------
                Are any health problems aggravated by caffeine?

Caffeine or other ingredients in coffee may exacerbate certain health
conditions:

HEARTBURN - In some people, coffee has been shown to relax the sphincter
muscles at the lower end of the esophagus, allowing the stomach contents to
"back up" into the esophagus; this is called heartburn.  Caffeine alone has no
effect on the sphincter muscles, so other substances in coffee apparently cause
the heartburn.

ULCERS - Caffeine can increase the secretion of both acid and pepsin in the
stomach, which could exacerbate an existing ulcer.  However, since both
"regular" and decaffeinated coffees have also been shown to stimulate the
gastric mucosa and increase stomach acid secretion, caffeine is probably not
the only component of coffee responsible.

-------------------------------- Page 15 of 21 --------------------------------
Are any health problems aggravated by caffeine?

HEART PROBLEMS - Caffeine has been shown to cause cardiac arrhythmias
(irregular heartbeats) in certain individuals; often persons with heart disease
are told to avoid caffeine altogether.  However, no evidence shows that
caffeine is a causative factor in the development of heart disease.  Also see
"Has coffee drinking been linked to heart disease?" in this section.

FIBROCYSTIC BREAST DISEASE - In the late '70's and '80's, several well-
publicized studies linked caffeine consumption with benign fibrocystic breast
disease (FBD).  More recent investigations, however, have not supported these
findings.  Individual women may notice a decrease in palpable breast lumps, the
symptoms of FBD, when they limit their caffeine intake, although research has
not shown a direct association.



-------------------------------- Page 16 of 21 --------------------------------
              Is it dangerous for pregnant women to drink coffee?

It has long been known that caffeine and the other xanthines can cross the
placenta and also pass into breast milk.  It takes 18-20 hours for pregnant
women to metabolize half of the caffeine consumed.  Concern about what effects
caffeine consumption may have on pregnancy and the developing fetus began to
arise during the late 1970's.  After much investigation the FDA now says,
"there is no human evidence at this time to suggest that moderate caffeine
consumption by pregnant women causes birth defects. MODERATION in the
consumption of caffeine-containing foods, beverages, and drugs, however, should
be emphasized."






-------------------------------- Page 17 of 21 --------------------------------
Is it dangerous for pregnant women to drink coffee?

In l980 the FDA advised pregnant women to reduce their intake of caffeine,
based on studies done on pregnant rats, who were given large quantities of
caffeine by a stomach tube.  Their offspring were born with missing toes or
parts of toes.  Birth defects were seen at the highest dose levels, equivalent
to 56-87 cups of strong coffee, given all at one time.  Low and middle dosages,
the equivalent of 4, 8, and 28 cups of coffee per day, produced no birth
defects. In further research, pregnant rats were given caffeine in water they
sipped throughout the day, more closely resembling human consumption.  The
offspring of rats that "sipped" high doses of caffeine did not show any of the
birth defects seen in the offspring of rats force-fed caffeine.





-------------------------------- Page 18 of 21 --------------------------------
Is it dangerous for pregnant women to drink coffee?

During the 1980's several studies of the incidence of birth defects in children
and caffeine consumption by their mothers found no links.  One study involved
more than 12,000 women who were questioned soon after delivery about their
coffee and tea consumption.  No relationship was found between low birth
weight, premature delivery, or any excess malformations among their babies.
Another study involved 2,030 infants who were examined  for a relationship
between their mother's caffeine intake during pregnancy and six specific birth
defects.  The findings were again negative and the authors concluded that
maternal ingestion of caffeine in tea, coffee, and cola has a minimal effect,
if any, on incidence of those six birth defects.
( Adapted from "Evaluation of Caffeine Safety," A Scientific Status Summary by
the Institute of Food Technologists' Expert Panel on Food Safety and
Nutrition., April, l983.)


-------------------------------- Page 19 of 21 --------------------------------
               Has coffee drinking been linked to heart disease?

The relationship between coffee drinking and heart disease has been
investigated in numerous studies but strong, independent risks associated with
coffee drinking have not been clearly documented.  Researchers at Johns Hopkins
Medical Institute recently found heavy coffee drinkers (defined as five or more
cups per day) were two to three times more likely to have coronary heart
disease than were nondrinkers (NEJM, October 16, 1986).  This relationship was
true even when accounting for other important risk factors such as age, smoking
habits, serum cholesterol and blood pressure.

However, the study did not control for the effects of diet, sedentary lifestyle
or high levels of occupational stress.  Nor did it indicate the exact quantity
in ounces of coffee consumed, the type of coffee (regular or decaffeinated),
the brewing method, or the use of cream or sugar.


-------------------------------- Page 20 of 21 --------------------------------
Has coffee drinking been linked to heart disease?

If coffee drinking does increase the risk of heart disease, it may do so
through its effect on cholesterol.  A few studies have linked heavy coffee
consumption to elevated total serum cholesterol, although caffeine alone does
not seem to be responsible.  Perhaps it's not even the coffee, but a high
saturated fat diet among heavy coffee drinkers that's increasing the risk of
heart disease. Increased coffee consumption by men has been associated with
increased calorie consumption from fat and increased cholesterol intake.
(Adapted from DNS ALERT, Cornell Cooperative Extension, Dec. 1986)







-------------------------------- Page 21 of 21 --------------------------------
               Is it true that coffee drinking can cause cancer?

Earlier research studies suggested a link between coffee consumption and lower
urinary tract cancer, renal (kidney) cancer, and pancreatic cancer, causing
widespread concern among coffee drinkers.  However, follow-up research has
revealed a number of inconsistencies and serious design flaws in these studies.
Several, for instance, did not control for the variable of smoking, which has
causative links to many types of cancer.  As it stands now, no clear evidence
links coffee consumption to any type of cancer.








