That cup of coffee that
many gym rats, bikers and runners swill before a
workout does more than energize them. It kills some
of the pain of athletic exertion, a new study
suggests. And it works regardless of whether a
person already had a coffee habit or not.
Caffeine works on a system in
the
brain and spinal cord (the adenosine
neuromodulatory system) that is heavily involved in
pain processing, says University of Illinois
kinesiology and community health professor Robert
Motl. And since caffeine blocks adenosine, the
biochemical that plays an important role in energy
transfer and thus
exercise, he speculated that it could reduce
pain.
So
the researcher, a former competitive cyclist,
divided 25 fit, college-aged males into two distinct
groups: subjects whose everyday
caffeine consumption was extremely low to
non-existent, and those with an average caffeine
intake of about 400 milligrams a day, the equivalent
of three to four cups of coffee.
Unexpected
results
After completing an initial exercise test in the lab
on a stationary bike to determine maximal oxygen
consumption or aerobic power, subjects returned for
two monitored high-intensity, 30-minute exercise
sessions.
An hour prior to each session, cyclists — who had
been instructed not to consume caffeine during the
prior 24-hour period — were given a pill. On one
occasion, it contained a dose of caffeine measuring
5 milligrams per kilogram of body weight (equivalent
to two to three cups of coffee); the other time,
they received a placebo.
During both exercise periods, subjects' perceptions
of quadriceps muscle pain was recorded at regular
intervals, along with data on oxygen consumption,
heart rate and work rate.
"What we saw is something we didn't expect," Motl
said. "Caffeine-naïve individuals and habitual users
have the same amount of reduction in pain during
exercise after caffeine (consumption)."
The results are detailed in the April edition of the
International Journal of Sport Nutrition and
Exercise Metabolism. Co-authors included Steven
P. Broglio of the University of Illinois and
Sigurbjorn A. Arngrimsson of the Center for Sport
and Health Sciences, Iceland University of
Education.
"Clearly, if you regularly consume caffeine, you
have to have more to have that bigger, mental-energy
effect," Motl said. "But the tolerance effect is not
ubiquitous across all stimuli. Even brain metabolism
doesn't show this tolerance-type effect. That is,
with individuals who are habitual users versus
non-habitual users, if you give them caffeine and do
brain imaging, the activation is identical. It's
really interesting why some processes show tolerance
and others don't."
Regarding the outcome of the current research, he
said, it may be that tolerance to caffeine plays no
role in the way it diminishes pain during exercise.
Motl said one of the next logical steps for his
research team would be to conduct studies with
rodents in order to better understand the biological
mechanism for caffeine in reducing pain.
"If we can get at the biological mechanism, we can
begin to understand why there may or may not be this
kind of tolerance."
Will it help you win?
Motl previously has conducted other studies on the
relationship between physical activity and caffeine,
and considered such variables as exercise intensity,
dose of caffeine, anxiety sensitivity and gender. A
future research direction might be to determine
caffeine's effect on sport performance.
"We've shown that caffeine reduces pain reliably,
consistently during cycling, across different
intensities, across different people, different
characteristics. But does that reduction in pain
translate into an improvement in sport performance?"
he said.
Meanwhile, the current
research could prove encouraging for a range of
people, including the average person who wants to
become more physically active to realize the health
benefits.
"One of the things that may be a practical
application, is if you go to the gym and you
exercise and it hurts, you may be prone to stop
doing that because pain is an aversive stimulus that
tells you to withdraw," Motl said. "So if we could
give people a little caffeine and reduce the amount
of pain they're experiencing, maybe that would help
them stick with that exercise."
© 2009 LiveScience.com |
In more good news for
coffee lovers, a new study suggests that middle-aged
adults who regularly drink a cup of java may have a
lower risk of developing dementia later in life.
Whether coffee itself deserves the credit is not yet
clear, but researchers say the findings at least
suggest that coffee drinkers can enjoy that morning
cup "in good conscience."
The study found that among 1,400 Finnish adults
followed for 20 years, those who drank three to five
cups of coffee per day in middle-age were two-thirds
less likely than non-drinkers to develop dementia,
including Alzheimer's disease.
The findings, reported in the Journal of Alzheimer's
Disease, add to a string of studies finding that
coffee drinkers have lower risks of several
diseases, including Parkinson's disease, certain
cancers and
diabetes.
No one is recommending that people start drinking
coffee to ward off any disease, however. Researchers
do not know if it's components of coffee itself —
like caffeine or certain antioxidants — or something
else about coffee drinkers that explains the recent
study observations.
The current study was an epidemiological one,
explained lead researcher Marjo H. Eskelinen, which
means it can point to an association between coffee
and dementia risk, but does not prove
cause-and-effect.
Still, "the results open a possibility that dietary
interventions could modify the risk of dementia,"
Eskelinen, a doctoral candidate at the University of
Kuopio in Finland, told Reuters Health.
There are a few potential reasons why coffee could help stave off dementia, researchers point out. One reason is related to the fact that coffee drinkers may have a lower risk of type 2 diabetes, and diabetes, in turn, is linked to a higher risk of dementia.
Coffee also contains plant chemicals, such as chlorogenic acid, that act as antioxidants and may help protect body cells from damage over time. For its part, caffeine may have a protective effect on brain cells because it blocks receptors for a chemical called adenosine, which has depressant effects in the central nervous system.
More research is needed to determine whether coffee is truly protective, but for now, Eskelinen said, "those people who have been drinking coffee can still do so in good conscience."
© 2009 Reuters.
|
Long-term coffee drinking does not appear to increase a person’s risk of early death and may cut a person’s chances of dying from heart disease, according to a study published on Monday. Previous studies have given a mixed picture of health effects from coffee, finding a variety of benefits and some drawbacks from the popular drink. The new study looked at people who drank caffeinated or decaffeinated coffee.
Researchers led by Esther Lopez-Garcia of Universidad Autonoma de Madrid in Spain followed 84,214 U.S. women from 1980 to 2004 and 41,736 U.S. men from 1986 to 2004.
They found that regular coffee drinking — up to six cups a day — was not associated with increased deaths among the study’s middle-aged participants. In fact, the coffee drinkers, particularly the women, experienced a small decline in death rates from heart disease.
The study found no association between coffee consumption and cancer deaths.
“Our study indicates that coffee consumption does not have a detrimental effect,” Lopez-Garcia, whose research appears in the journal Annals of Internal Medicine, said in a telephone interview. “It seems like long-term coffee consumption may have some beneficial effects.”
There has been a debate among scientists about the health effects of drinking coffee, which typically contains the stimulant caffeine and a number of other important compounds.
The people who took part in the research completed questionnaires on how frequently they drank coffee, other diet habits, smoking and medical conditions. The researchers then studied the mortality risk over the period of the study among people with different coffee-drinking habits.
The study found that women who reported drinking two to three cups of caffeinated coffee per day had a 25 percent lower risk of death from heart disease than women who did not drink coffee. The researchers saw a smaller decreased risk for men but it was not statistically significant.
Drinking decaffeinated coffee was associated with a small reduction in overall mortality risk, the researchers said.
The people in the study had no history of cardiovascular disease or cancer when they entered it. The women were nurses and the men doctors, dentists and other health professionals.
Some studies have indicated coffee is a great source of antioxidants, substances that may protect against the effects of molecules called free radicals that can damage cells and may play a role in heart disease, cancer and other ailments.
Recent studies have offered a mixed picture on the health effects of coffee.
A study that came out in January found that pregnant women who drink two or more cups of coffee a day had twice the risk of miscarriage as those who avoid caffeine. Another study appearing in January found that drinking caffeinated coffee lowered a woman’s risk of ovarian cancer.
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