Monday, April 11, 2011

coffee, caffeine, and the endurance athlete

i'll be the first to admit i like coffee. not to the point where it's a compulsion or craving, but definitely to the point that it's something (at times, the one thing) that i yearn for on certain occasions--like just after waking up on a cold winter morning, or right after dinner with a post-meal dessert, or a little bit before a long day's workout as the realization of what i'm about to do sinks into me.

i'm sure it has to do with the kick-start that comes with the injection of caffeine (something that as become noticeably more necessary as i've gotten older). but there's something beyond that, too: there's something about the taste and smell of coffee that's becoming comforting, almost reassuring, and aids the transition between the phases of the day. that, and there's just something about taking several minutes to hold a cup of hot coffee and sip its steamy goodness for; it's a moment of civilization for our all-too uncivilized times.

i'm suspect i'm not alone. in fact, i'm sure i'm not alone. i know a fair number of people, even within the athlete (professional, elite, recreational, or otherwise) community who always find that things go better with a cup of coffee to start their days. some i know can't function without it.

which is funny, because there's been controversy over the years about the issue of coffee relative to sports. not purely for the performance-related questions about its caffeine, but for its overall affect on athlete health.

well, you can add this recent piece to the discourse (as usual, if the link doesn't work i've put the full text of the article at the end of this post):
the article summarizes the state of research regarding coffee (and its caffeine content) and health, and finds that most recent research indicates that it is good for you. apparently, past science was based on limited population samples or restricted data.

i certainly find this reassuring, but i figured it'd be worthwhile to also reference some additional sources to further illuminate the issue, particularly in relation to endurance sports. most of what i found deals with the question of caffeine and sports, but i did find some that were more germane to endurance athletes:
essentially, i'll summarize them in terms of what they say about the performance benefits of caffeine and its potential dangers.

in terms of performance benefits, this is what the research seems to show about caffeine (and hence coffee) and endurance sports:
  • performance-wise, one theory is that caffeine assists the body in utilizing fat as a source of energy. in endurance sports, this is important, as the glycogen used by the body for fuel exists in much greater quantity in fats than in carbohydrates, with carbohydrates typically only providing an athlete about 90-150 minutes (depending on the individual and the circumstances) of sustained activity and fast providing much longer reserves.
  • another theory is that caffeine helps the body improve the release of calcium into the body. this allows the muscular and bioelectrical systems to sustain muscle contraction for longer periods of time. this is an obvious benefit for endurance sports, where the priority is maintaining continuous muscular activity over an extended duration.
in terms of potential dangers with caffeine, this is what the research notes:
  • organized sports have placed, or are beginning to place, standards regarding allowable levels of caffeine in athletes. caffeine is seen as an ergogenic aid (i.e., it improves performance), and so is subject to limits. in the U.S., for example, the National Collegiate Athletics Association (NCAA, the organization that oversees major organized collegiate sports), sets a limit of 12mg/liter of caffeine in test samples from any student athlete. athletes who test beyond this are potentially subject to sanctions, as are their schools.
  • caffeine is a diuretic, which risks inducing dehydration and thereby causing muscle cramps. neither of these are desirable for athletes.
caffeine is a stimulant affecting the neuromuscular system, and so excites bio-electrical pathways related to movement control. for some athletes, however, this means a distortion of their motor coordination to a degree that is detrimental to their performance. most of us had experienced the "shakes" that comes with drinking copious amounts of coffee, and realized the affect it's had on our bodily comfort level. well, this also means it's affected our physical coordination, and hence athletic ability.

personally, i've always enjoyed having a little coffee (less than a cup) before long workouts (especially the long bike rides training for Ironman). i've suffered the diuretic affects, but have always been willing and able to deal with them. i've never been aware of any performance benefits, but it certainly made a difference in my comfort level going from early-morning grogginess to full-on workout mode.

having said that, i'm very much aware that the affect of caffeine varies by the athlete, and that some find coffee and caffeine better than others. some, i know, avoid it like the plague. i don't think there's any real strict rules at this point, and it's largely up to the individual to figure out what benefit caffeine has for them. assuming they stay within the limitations set by the governing bodies of their sports, it's something that each person can decide for themselves.

of course, there are those who are addicted to their coffee. for them, i offer this:
these articles basically note that some people have a genetic predisposition for coffee, either towards the caffeine or otherwise. in which case, their proclivities may be somewhat out of their control.

in which case, all i can say is: condolences? congratulations? commiseration?

and would you like some coffee?

Nutrition Lab
Coffee Studies Should Warm Your Heart

By Elena Conis, Special to the Los Angeles Times
April 10, 2011

Looking for a reason to not give up your coffee habit? Here's one possibility: heart health.

Numerous studies in recent years have reported that drinking coffee may be good for the cardiovascular system and might even help prevent strokes. Just last month, Swedish researchers announced results of a large study showing that coffee seemed to reduce the risk of stroke in women by up to 25%.

Not long ago, researchers thought quite the opposite about coffee and the heart, says Dr. Thomas Hemmen, director of the UC San Diego Stroke Center: "Coffee is fun and it tastes good, so people assumed for many years that it would be bad for you."

Studies conducted in the 1970s and 1980s offered little in the way of confirmation or refutation. Several suggested an increased risk of heart attack among coffee drinkers. Others showed a lowered risk of heart attack and stroke. Still others found no connection at all.

Many of these early studies were criticized for being too small or too brief. In response, researchers at the Harvard School of Public Health decided to look at coffee consumption, heart disease and stroke risk among more than 45,000 healthy men enrolled in the school's ongoing Health Professionals Follow-Up Study. Their analysis, published in the New England Journal of Medicine in 1990, found that coffee drinking had no effect on the men's risk of heart attack or stroke.

But in the last few years, a spate of studies has revisited the question, and many of them have found — unexpectedly — that coffee drinking is linked to a decreased stroke risk.

A 2008 study of more than 26,000 male smokers in Finland found that the men who drank eight or more cups of coffee a day had a 23% lower risk of stroke than the men who drank little or no coffee. And a few other reports suggest the effect applies to healthy nonsmokers too. Researchers at UCLA and USC examined data on coffee consumption and stroke prevalence among more than 9,000 participants in the National Health and Nutrition Examination Survey. At a 2009 conference, they reported that the likelihood of stroke was highest among people who didn't drink coffee and lowest among those who drank the most coffee: 5% of people who drank one or two cups a day suffered strokes, whereas 2.9% of people who drank six or more cups suffered strokes. The study will be published in a few months.

Results from an even larger study of coffee drinking and stroke risk were published in the journal Circulation in 2009: Among the 83,000 women enrolled in Harvard's ongoing Nurses' Health Study, those who drank two to four cups of coffee a day had a 19% to 20% lower risk of stroke than women who drank less than one cup a month.

And this year, a study of more than 81,000 men and women in Japan showed that drinking one or two cups of coffee a day reduced the risk of death from cardiovascular disease by up to 23%. The findings were published in the Journal of Epidemiology and Community Health.

Such studies reveal that coffee isn't harmful, as once thought, and might even be beneficial, says Dr. Larry Goldstein, professor of medicine and director of the Duke University Stroke Center. But while they show an association between coffee drinking and lower stroke risk, they still don't prove that coffee is the cause, he says.

"People who drink coffee are different in many ways from those who don't drink coffee," says Dr. Nerses Sanossian, one of the authors of the UCLA-USC study and a professor of neurology at USC.

Any one of those differences, or more than one of them, could be behind the apparently lower stroke risk. Some of the studies that show a link between coffee drinking and reduced stroke risk have also shown that coffee drinkers are more likely to smoke, have lower education levels and have diets higher in potassium. And although it's unlikely that smoking, for instance, is behind their reduced stroke risk, it's possible that something else is. "It may be due to some other factors we haven't even taken into consideration," Sanossian says.

Even though coffee is considered safe, even in large amounts, you shouldn't rush to take up the habit, says Mark Urman, a cardiologist at the Cedars-Sinai Heart Institute. "If you're not a coffee drinker, don't start drinking to prevent a stroke or otherwise," he says. Coffee can cause heart palpitations in some people, and withdrawal symptoms in those who try to skip their daily cups for a day or two. And many people, he adds, like to load their coffees with cream and sugar, which could very well counteract any advantage coffee has for the blood vessels and heart.

Definitive proof that coffee is good for the blood vessels is unlikely to emerge anytime soon, Hemmen says. Such studies would need to randomly select people to drink either a lot of coffee or a little coffee, and then researchers would have to closely monitor their coffee intake and health for decades.

And that, says Hemmen, would be "very difficult, and really expensive."

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