When Dr. John Cianca of Baylor College of Medicine in Houston took over as the medical director of the Houston Marathon in 1998, what many athletes believed about proper hydration was, in effect, that too much is never enough. And so the Houston Marathon course had 26 water stations -- one every mile. Then, in 1999, four runners collapsed after the race and had to be hospitalized, all of them in critical condition. Cianca was flabbergasted when he got word that each of the runners was suffering from severe hyponatremia, or overhydration. ''The thinking back then was that it was difficult to develop hyponatremia during a marathon,'' Cianca says. ''Obviously, that was wrong.''
Two deaths in 2002 proved that too much can indeed be way more than enough: First, a 28-year-old woman collapsed near the 22-mile mark of the Boston Marathon. She lapsed into a coma and was declared brain-dead from intracranial swelling caused by hyponatremia. Six months later, at the Marine Corps Marathon in Washington, D.C., a 35-year-old woman collapsed five hours into the race. She died two days later, also from complications of overhydration.
At Cianca's urging, the organizers of the Houston Marathon cut the number of water stations along the course by half in 2003. Some runners were worried at first, but there have been few complaints. ''We're doing our best to reduce the availability of fluids,'' Cianca says. ''We're trying to take away the choice to overhydrate.''
Welcome to the age of hydration anxiety. Hyponatremia is a big topic in sports medicine and has become a growing concern for race directors. The American College of Sports Medicine, U.S.A. Track & Field, the National Athletic Trainers' Association and the Association of International Marathon Medical Directors have all recently issued revised fluid-intake guidelines that warn athletes not to overdo it. And in the past year or so newspapers across the land have run headlines like this one from the Chicago Sun-Times: ''Drink Tons of Water While Running? Not If You Want to Live.''
With this comes the inevitable backlash. ''There's a big danger of going too far,'' says Dr. Larry Kenney, a professor of physiology and kinesiology at Penn State University and a past president of the American College of Sports Medicine. ''Some susceptible athletes will hear this and overdo it and not drink enough, or at all.''
It used to be so easy: you did your workout, you replenished your fluids. But as physiology continues to teach us, nothing is that simple. Not even a drink of water.
Drinking too much is dangerous because it dilutes the blood's sodium content, which may already be lowered during prolonged exercise, since salt is lost in sweat. Meanwhile, sodium levels within other cells -- in the skin, muscles and internal organs -- remain constant. To correct the imbalance, osmosis draws water out of the blood, causing the cells to become engorged. Hands and feet balloon. The chest may feel constricted. In extreme cases, the brain can swell, leading to disorientation, fainting, a coma, even death.
Athletes who exercise for relatively short periods of time (less than two hours or so) rarely suffer from hyponatremia. Top finishers in marathons, triathlons and bike races also are not prone to develop symptoms, nor are athletes in fast-paced games like basketball and tennis. It is, instead, the slow back-of-the-packers who are at risk. As one doctor noted in The Physician and Sportsmedicine, slower marathon racers were found to have drunk as much as six or seven liters (more than 200 ounces) of fluid during the 26-mile event. By contrast, the top runners rarely drank more than two or three liters. And unlike the speedsters, the plodders did not work up as much of a sweat, so they took in fluids at a much higher rate than they expended them.
Until quite recently, few people drank to excess. Then came Oprah. Remember her famous 1994 marathon run? She inspired a slew of enthusiastic but decidedly unathletic imitators. They came, they jogged, they walked, they chatted -- and they made a day of it. Before Oprah, women tended to finish a marathon in a little more than four hours. Now they finish in closer to five, dutifully hydrating along the way.
How can you tell if you're drinking too much? The first symptom is often a sense that your wedding ring or running shoes are becoming tight, or that your waistband pinches. Overhydrators typically end their workouts weighing more than they did when they started. ''You'll see these runners put on as much as four to eight pounds by the end'' of a five-hour marathon, all of it from fluid, says Dr. Douglas Casa, the director of athletic-trainer education at the University of Connecticut and an author of U.S.A. Track & Field's hydration guidelines.
The risk of hyponatremia is disproportionately higher in women, although not for any innate physiological reasons. ''Women are generally just more conscientious than men,'' says Dr. Timothy Noakes, a professor of exercise and sports science at the University of Cape Town in South Africa and a longtime crusader against hyponatremia. ''Women do what they're told, and they've been told to drink as much as they can hold. So they do.''
Noakes likes the old-fashioned idea that if you're thirsty it's time to drink. ''Athletes are still told, 'Stay ahead of your thirst,' which is terrible advice,'' he says. ''Thirst is nature's way of helping you hydrate correctly. If you drink only when you're thirsty and stop when you're not, you'll be in good shape.''
Other physiologists strongly disagree. ''By the time you feel thirst, you 've typically lost at least 2 percent of your body weight'' to dehydration, Casa says. Losing as little as 3 percent of your weight can affect athletic performance, he continues. (Noakes disputes this; his research, he says, suggests that performance is not affected until athletes have lost at least 8 percent of their weight, if then.) Even slightly dehydrated athletes can feel hot, tired, irritable and sluggish. A more extreme case of dehydration can contribute to the development of minor heat exhaustion or even heat stroke.
''When you reduce the volume of blood'' -- as happens if you sweat and don 't replace fluid -- ''the heart has to work harder,'' Larry Kenney says. Heat builds up in the body. Your sweat rate might drop, increasing internal temperature even more. Like a malfunctioning boiler, the body has to slow down or it will blow.
Children are particularly susceptible to dehydration. ''Kids do a pretty poor job of hydrating themselves,'' says Casa, who, in a study of elementary-school-age soccer players, found that most of them arrived at their summer practices already dehydrated, complaining of thirst and acting listless. Among the most disastrously at risk are youth football players practicing in full gear in full summer heat. ''In the past 10 years, 26 young football players have died from heat stroke (20 high school, 4 college and 2 professional),'' according to a report issued this year by the National Center for Catastrophic Sport Injury Research at the University of North Carolina at Chapel Hill. In many instances, the players were severely dehydrated before they collapsed. Each of these deaths could have been avoided, the report concluded (with subtextual pathos), if fluids had been plentiful at the field.
So how much should an athlete drink? Experts like the nabobs at the American College of Sports Medicine no longer make blanket recommendations; each person's physique is too singular. To put it less delicately, some of us sweat like an ironworker and some don't. ''Two people of approximately the same size and athletic ability can have very different sweat rates,'' Kenney says. If both are told to drink the same amount, it's likely that one or both of them will be drinking too much or not enough.
Instead, physiologists now give guidelines for testing individuals' sweat rates and fluid requirements. For one, they say, check your urine. It should be clear and pale. If it's dark or cloudy, you may be dehydrated. Ditto if your skin, when pinched, doesn't replump. Before you exercise, weigh yourself. Monitor how much you drink during your workout, then weigh yourself again afterward. ''If you've lost weight, you need to start drinking a little more every hour,'' Casa says. ''If you've gained weight, you need to drink less.'' At the Houston Marathon, scales are now set at the runner check-in area and also at strategic points along the course itself, so that both the participants and the medical team can record weight gain or loss.
As for what to drink, almost any fluid will do. The small amount of salt in sports drinks will not stave off the sodium dilution characteristic of hyponatremia. In a study conducted by Harvard researchers, runners at the 2002 Boston Marathon who developed hyponatremia were as likely to have overindulged in Gatorade as in water. It was the amount they drank, not the content, that mattered.
''For general hydration, if you like water, by all means, drink water,'' Casa says. ''If you find sports drinks more palatable, drink those.''
It's maddeningly vague, this question of how much to drink and when, but one overarching message is clear. Think Goldilocks. ''The word I like to stress is 'appropriate,''' Casa says. ''Not too much and not too little.'' Just right.
1. Drink Eight Glasses of Water A Day. No science supports this, as the Dartmouth College physiologist Heinz Valtin discovered during a 2002 review of more than 30 years' worth of nutrition studies. The average daily water intake ''of thousands of presumably healthy humans'' in these studies was closer to four glasses. If you want more exactitude in your intake reckonings, consult the Gatorade Sport Science Institute's fluid-loss calculator at www.gssiweb.com.
2. Only Fluids Count. Food, especially watery items like fruit or ice cream, can contribute up to 20 percent of your daily fluid intake.
3. Avoid Coffee. It can be a diuretic, but typically only to those new to caffeine. A 2000 study at the University of Nebraska Medical Center found no difference in hydration levels between those who swigged water and those who drank coffee.
4. We all sweat the same stuff. Some people are what physiologists refer to as salty sweaters. If your clothes and skin have a white film after a workout, you're probably a salty sweater, and you should be diligent about replacing lost sodium by salting your food more heavily, especially during the summer.
5. Sports Drinks Are the Best Way to Replace sodium and potassium. Many people assume that sports drinks replenish those electrolytes. Not so, though the glucose in them provides easily digested calories, which are important during prolonged, high-intensity workouts. Potassium losses during exercise are negligible, and ''sports drinks don't contain enough salt to make any difference,'' says Dr. Timothy Noakes, a South African physician and an expert on hydration. ''You'd have to drink seawater, which has three times the sodium content of blood.''
URL: http://www.nytimes.com
GRAPHIC: Photos (PHOTOGRAPHS BY TONY CENICOLA/THE NEW YORK TIMES)(pg. 32) (PHOTOGRAPH BY DAN FORBES)(pg. 30)
1 Comments:
Here is a very good article Craig found in the New York Times Magazine on hydration:
Time of Request: June 09, 2006 02:09 PM EDT
Number of Lines: 123
Job Number: 1841:102928265
Client ID/Project Name:
Research Information:
Note:
1 of 1 DOCUMENT
Copyright 2006 The New York Times Company
The New York Times
June 4, 2006 Sunday
Late Edition - Final
SECTION: Section 6; Column 1; Sports Desk; PHYS ED; Pg. 30
LENGTH: 1850 words
HEADLINE: Hydration Angst
BYLINE: By Gretchen Reynolds
BODY:
When Dr. John Cianca of Baylor College of Medicine in Houston took over as
the medical director of the Houston Marathon in 1998, what many athletes
believed about proper hydration was, in effect, that too much is never enough.
And so the Houston Marathon course had 26 water stations -- one every mile.
Then, in 1999, four runners collapsed after the race and had to be hospitalized,
all of them in critical condition. Cianca was flabbergasted when he got word
that each of the runners was suffering from severe hyponatremia, or
overhydration. ''The thinking back then was that it was difficult to develop
hyponatremia during a marathon,'' Cianca says. ''Obviously, that was wrong.''
Two deaths in 2002 proved that too much can indeed be way more than enough:
First, a 28-year-old woman collapsed near the 22-mile mark of the Boston
Marathon. She lapsed into a coma and was declared brain-dead from intracranial
swelling caused by hyponatremia. Six months later, at the Marine Corps Marathon
in Washington, D.C., a 35-year-old woman collapsed five hours into the race. She
died two days later, also from complications of overhydration.
At Cianca's urging, the organizers of the Houston Marathon cut the number of
water stations along the course by half in 2003. Some runners were worried at
first, but there have been few complaints. ''We're doing our best to reduce the
availability of fluids,'' Cianca says. ''We're trying to take away the choice to
overhydrate.''
Welcome to the age of hydration anxiety. Hyponatremia is a big topic in
sports medicine and has become a growing concern for race directors. The
American College of Sports Medicine, U.S.A. Track & Field, the National Athletic
Trainers' Association and the Association of International Marathon Medical
Directors have all recently issued revised fluid-intake guidelines that warn
athletes not to overdo it. And in the past year or so newspapers across the land
have run headlines like this one from the Chicago Sun-Times: ''Drink Tons of
Water While Running? Not If You Want to Live.''
With this comes the inevitable backlash. ''There's a big danger of going
too far,'' says Dr. Larry Kenney, a professor of physiology and kinesiology at
Penn State University and a past president of the American College of Sports
Medicine. ''Some susceptible athletes will hear this and overdo it and not drink
enough, or at all.''
It used to be so easy: you did your workout, you replenished your fluids.
But as physiology continues to teach us, nothing is that simple. Not even a
drink of water.
Drinking too much is dangerous because it dilutes the blood's sodium
content, which may already be lowered during prolonged exercise, since salt is
lost in sweat. Meanwhile, sodium levels within other cells -- in the skin,
muscles and internal organs -- remain constant. To correct the imbalance,
osmosis draws water out of the blood, causing the cells to become engorged.
Hands and feet balloon. The chest may feel constricted. In extreme cases, the
brain can swell, leading to disorientation, fainting, a coma, even death.
Athletes who exercise for relatively short periods of time (less than two
hours or so) rarely suffer from hyponatremia. Top finishers in marathons,
triathlons and bike races also are not prone to develop symptoms, nor are
athletes in fast-paced games like basketball and tennis. It is, instead, the
slow back-of-the-packers who are at risk. As one doctor noted in The Physician
and Sportsmedicine, slower marathon racers were found to have drunk as much as
six or seven liters (more than 200 ounces) of fluid during the 26-mile event. By
contrast, the top runners rarely drank more than two or three liters. And unlike
the speedsters, the plodders did not work up as much of a sweat, so they took in
fluids at a much higher rate than they expended them.
Until quite recently, few people drank to excess. Then came Oprah. Remember
her famous 1994 marathon run? She inspired a slew of enthusiastic but decidedly
unathletic imitators. They came, they jogged, they walked, they chatted -- and
they made a day of it. Before Oprah, women tended to finish a marathon in a
little more than four hours. Now they finish in closer to five, dutifully
hydrating along the way.
How can you tell if you're drinking too much? The first symptom is often a
sense that your wedding ring or running shoes are becoming tight, or that your
waistband pinches. Overhydrators typically end their workouts weighing more than
they did when they started. ''You'll see these runners put on as much as four to
eight pounds by the end'' of a five-hour marathon, all of it from fluid, says
Dr. Douglas Casa, the director of athletic-trainer education at the University
of Connecticut and an author of U.S.A. Track & Field's hydration guidelines.
The risk of hyponatremia is disproportionately higher in women, although
not for any innate physiological reasons. ''Women are generally just more
conscientious than men,'' says Dr. Timothy Noakes, a professor of exercise and
sports science at the University of Cape Town in South Africa and a longtime
crusader against hyponatremia. ''Women do what they're told, and they've been
told to drink as much as they can hold. So they do.''
Noakes likes the old-fashioned idea that if you're thirsty it's time to
drink. ''Athletes are still told, 'Stay ahead of your thirst,' which is terrible
advice,'' he says. ''Thirst is nature's way of helping you hydrate correctly. If
you drink only when you're thirsty and stop when you're not, you'll be in good
shape.''
Other physiologists strongly disagree. ''By the time you feel thirst, you
've typically lost at least 2 percent of your body weight'' to dehydration, Casa
says. Losing as little as 3 percent of your weight can affect athletic
performance, he continues. (Noakes disputes this; his research, he says,
suggests that performance is not affected until athletes have lost at least 8
percent of their weight, if then.) Even slightly dehydrated athletes can feel
hot, tired, irritable and sluggish. A more extreme case of dehydration can
contribute to the development of minor heat exhaustion or even heat stroke.
''When you reduce the volume of blood'' -- as happens if you sweat and don
't replace fluid -- ''the heart has to work harder,'' Larry Kenney says. Heat
builds up in the body. Your sweat rate might drop, increasing internal
temperature even more. Like a malfunctioning boiler, the body has to slow down
or it will blow.
Children are particularly susceptible to dehydration. ''Kids do a pretty
poor job of hydrating themselves,'' says Casa, who, in a study of
elementary-school-age soccer players, found that most of them arrived at their
summer practices already dehydrated, complaining of thirst and acting listless.
Among the most disastrously at risk are youth football players practicing in
full gear in full summer heat. ''In the past 10 years, 26 young football players
have died from heat stroke (20 high school, 4 college and 2 professional),''
according to a report issued this year by the National Center for Catastrophic
Sport Injury Research at the University of North Carolina at Chapel Hill. In
many instances, the players were severely dehydrated before they collapsed. Each
of these deaths could have been avoided, the report concluded (with subtextual
pathos), if fluids had been plentiful at the field.
So how much should an athlete drink? Experts like the nabobs at the
American College of Sports Medicine no longer make blanket recommendations; each
person's physique is too singular. To put it less delicately, some of us sweat
like an ironworker and some don't. ''Two people of approximately the same size
and athletic ability can have very different sweat rates,'' Kenney says. If both
are told to drink the same amount, it's likely that one or both of them will be
drinking too much or not enough.
Instead, physiologists now give guidelines for testing individuals' sweat
rates and fluid requirements. For one, they say, check your urine. It should be
clear and pale. If it's dark or cloudy, you may be dehydrated. Ditto if your
skin, when pinched, doesn't replump. Before you exercise, weigh yourself.
Monitor how much you drink during your workout, then weigh yourself again
afterward. ''If you've lost weight, you need to start drinking a little more
every hour,'' Casa says. ''If you've gained weight, you need to drink less.'' At
the Houston Marathon, scales are now set at the runner check-in area and also at
strategic points along the course itself, so that both the participants and the
medical team can record weight gain or loss.
As for what to drink, almost any fluid will do. The small amount of salt in
sports drinks will not stave off the sodium dilution characteristic of
hyponatremia. In a study conducted by Harvard researchers, runners at the 2002
Boston Marathon who developed hyponatremia were as likely to have overindulged
in Gatorade as in water. It was the amount they drank, not the content, that
mattered.
''For general hydration, if you like water, by all means, drink water,''
Casa says. ''If you find sports drinks more palatable, drink those.''
It's maddeningly vague, this question of how much to drink and when, but
one overarching message is clear. Think Goldilocks. ''The word I like to stress
is 'appropriate,''' Casa says. ''Not too much and not too little.'' Just right.
1. Drink Eight Glasses of Water A Day.
No science supports this, as the Dartmouth College physiologist Heinz Valtin
discovered during a 2002 review of more than 30 years' worth of nutrition
studies. The average daily water intake ''of thousands of presumably healthy
humans'' in these studies was closer to four glasses. If you want more
exactitude in your intake reckonings, consult the Gatorade Sport Science
Institute's fluid-loss calculator at www.gssiweb.com.
2. Only Fluids Count. Food, especially watery items like fruit or ice cream, can
contribute up to 20 percent of your daily fluid intake.
3. Avoid Coffee. It can be a diuretic, but typically only to those new to
caffeine. A 2000 study at the University of Nebraska Medical Center found no
difference in hydration levels between those who swigged water and those who
drank coffee.
4. We all sweat the same stuff.
Some people are what physiologists refer to as salty sweaters. If your clothes
and skin have a white film after a workout, you're probably a salty sweater, and
you should be diligent about replacing lost sodium by salting your food more
heavily, especially during the summer.
5. Sports Drinks Are the Best Way to Replace sodium and potassium.
Many people assume that sports drinks replenish those electrolytes. Not so,
though the glucose in them provides easily digested calories, which are
important during prolonged, high-intensity workouts. Potassium losses during
exercise are negligible, and ''sports drinks don't contain enough salt to make
any difference,'' says Dr. Timothy Noakes, a South African physician and an
expert on hydration. ''You'd have to drink seawater, which has three times the
sodium content of blood.''
URL: http://www.nytimes.com
GRAPHIC: Photos (PHOTOGRAPHS BY TONY CENICOLA/THE NEW YORK TIMES)(pg. 32)
(PHOTOGRAPH BY DAN FORBES)(pg. 30)
LOAD-DATE: June 4, 2006
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