1 "Kan water iemand vergiftigen?"
Te veel water kan in bepaalde gevallen inderdaad iemand vergiftigen. Dit heeft
te maken met de natriumbalans in je lichaam. De concentratie aan natrium in je
bloedcellen en in je lichaamscellen moet altijd in evenwicht zijn.
Watervergiftiging kan bijvoorbeeld voorkomen bij atleten die tijdens een
wedstrijd extreem veel zweten en dan in één keer liters water drinken.
Door te zweten verlies je water en zout, en in zout zit natrium.
Van zweten krijg je dorst, je lichaam vraagt om je vochtconcentratie terug op
peil te brengen. Door dan heel veel water te drinken wordt de hoeveelheid vocht
in je lichaam wel terug aangevuld, maar niet de hoeveelheid natrium die je
verloren bent. Hierdoor ontstaat er een onevenwicht in je lichaam tussen de
natriumconcentratie in je bloedcellen en in je lichaamscellen. Als gevolg
daarvan word je misselijk, krijg je braakneigingen of word je heel verward. Dit
wordt 'watervergiftiging' genoemd of met een geleerde naam 'hyponatremia'.
Daarom dat ook wel eens gezegd wordt dat je best zoute nootjes of iets anders
zout eet wanneer je extreem zware inspanningen doet en veel zweet.
In normale omstandigheden zal je echter niet gemakkelijk te veel drinken. Een
volwassen persoon drinkt best minstens 2 liter water per dag.
2 Hyponatremia: Water Hazard
Guzzle too much and you risk hyponatremia, a perilous drop in sodium. Here are
by: Marlene Cimons
What You Can Do
Hyponatremia can be deadly, but it's easily preventable. Here are some tips to
keep you safe.
- Stick to sports drinks that contain sodium. They can
replace what's lost through sweating.
- Unless you're on a salt-restricted diet, add salt to your food in the days
before a race.
- During the last half of your race, eat some salted pretzels if possible.
- Skip the salt tablets. "The sodium concentration may be too high, causing
vomiting, which will make matters worse," says Dr. Cianca.
- Don't take nonsteroidal anti-inflammatory drugs (such as aspirin, naproxen
sodium, and ibuprofen) before or during your race. If you must take a pain
reliever, acetaminophen (Tylenol) appears to be safer.
- Finally -- and probably most important of all -- don't drink more than you
How do you know how much you sweat? You can estimate your
sweat rate ahead of time by weighing yourself before and after running for an
hour at the pace and under the conditions anticipated in the race.
For every pound lost through sweating, drink 16 ounces per hour during your race
For years, runners have been told repeatedly that it's a good thing to drink --
and to drink often. Now it appears there can be too much of a good thing. To be
sure, dehydration is not to be ignored. You should still consume plenty of
sports drinks. But drinking large amounts of water can spell trouble. When you
saturate your body with water, you can develop a life-threatening condition
known as hyponatremia, a shortage of sodium in the blood. It occurs when runners
sweat excessively, lose too much salt, and then drink excessive amounts of water
-- which dilutes the blood's sodium content even more. This imbalance can cause
fatigue, weakness, cramping, nausea, vomiting, bloating and puffiness in the
face and fingers, dizziness, headache, confusion, fainting and unconsciousness,
pulmonary edema (fluid in the lungs), seizures, coma -- and sometimes even death.
"Symptoms tend to occur late in races, or even afterward," says John Cianca, M.D.,
assistant professor of physical medicine at Baylor College of Medicine in
Houston, and medical director of the Houston Marathon. "It can be confused with
Indeed, researchers at Baylor and at the University of California at San
Francisco, who studied seven cases of hyponatremia among marathoners-including
one death-warn that hyponatremia can be misdiagnosed, prompting the wrong
treatment. And if runners are given only water -- instead of fluids containing
salt -- it can have fatal consequences.
The researchers -- J. Carlos Ayus, M.D., Joseph Veron, M.D., and Allen I. Arieff,
M.D. -- writing in the May 2000 Annals of Internal Medicine, urge hospital
personnel to consider hyponatremia when treating collapsed marathon runners.
They should measure sodium levels and perform chest scans, doctors say, to see
if there are indications of hyponatremia -- and start sodium replacement if the
tests warrant it.
Hyponatremia is gaining more public attention lately, likely due to the
increasing number of slower marathoners who often heed warnings about the
dangers of dehydration by drinking copious amounts of water in the days
preceding their race and during the marathon itself. At the same time, the race
circuit is becoming more aware of the problem and trying to do something about
it. Lewis G. Maharam, M.D., medical director of the New York City, Country Music,
and Rock 'N' Roll marathons, insists that all runners receive hyponatremia
information in their race packets. The instructions warn: "Don't overdrink --
too much is as bad as too little." These marathons also stock their medical
tents with salted pretzels and hand them out if they suspect a runner's salt
levels are dangerously low. They're even considering adding salted pretzels to
aid stations along the course.
3 The Dangers of Hot Weather Running
Dehydration, Heat Cramps, Heat Exhaustion, Heatstroke &
Hyponatremia. By Claudio Piepenburg
Originally published by Road Runner Sports
Running in hot weather can pose dangers to runners. Particularly dangerous is
racing in hot, humid summer conditions. Here’s how to protect yourself from
these five serious (and potentially fatal) conditions.
Dehydration is not limited only to the summer months, although it’s probably
more likely to occur during that time. Many physicians believe that most people
are in a constant state of dehydration. Since coffee, tea, soda and alcohol act
as a diuretic, anyone who drinks these fluids on a daily basis, and doesn’t
drink at least an equal amount of water, will probably be dehydrated. If the
person is physically active, the potential for dehydration is even greater.
Working out in hot, humid conditions promotes sweating, which in turn can cause
dehydration. Sweating is good for you because it cools your body, but when you
lose too much water you become dehydrated. If you’re already slightly dehydrated,
sweating will only make it worse. It’s important to maintain an adequate fluid
intake all the time. Don’t expect that you can make up for several days of not
drinking enough by downing two cups of sports drink before your next long run or
race. It’s important to keep hydrated all the time. Once you start to feel
thirsty, it’s too late.
The average (sedentary) person needs a minimum of eight 8-ounce glasses of fluid
a day. Runners need more: anywhere from four to eight quarts of fluid. That
translates to at least sixteen 8-ounce glasses daily. Remember that diuretics
don’t count! Drink water and sports drinks, and if you don’t have to worry about
calories, fruit drinks or juice.
Two hours before your daily summer workout or a race, you should drink 16 ounces
of fluid. Then ten minutes or so before you start to run, drink another one or
two cups of water or sports drink. Drinking early and drinking often is the key.
During a race you should drink six to twelve ounces of fluid every 15-20 minutes.
If the weather is very hot, you may need to drink even more. Training in warm
weather, you should drink at least every 35 to 40 minutes. (Remember you will
have already had two 8-ounce glasses before you started.) If you’re running a
race shorter than 30 minutes, you probably won’t need any water other than what
you drank before the start. The same goes for the last few miles of a longer
race. If you’re racing or training for longer than an hour, drink sports drinks
as opposed to strictly water.
Start drinking immediately after finishing a run, no matter if it was a race or
a workout. Minimum is 16 ounces for every 30 minutes you ran. If you tend to
sweat a lot, you’ll need more. Weigh yourself after you’ve run. Drink at least
16 ounces of fluid for every pound you lose through sweating.
By monitoring the color of your urine you can tell if you’re hydrated. It should
be pale yellow or even clear. If it isn’t, you need to drink more fluids. It’s
important that you retain the fluid, so be careful it you’re urinating every
fifteen or twenty minutes. To restore your fluid balance, eat something salty (a
bag of pretzels, salted nuts, crackers or potato chips), then drink a sports
drink. The salt will make you thirstier, so you’ll take in even more fluid and
urine production will decrease.
Have you ever seen a runner bent over at the side of the road massaging their
calves during a race? Chances are that he or she had heat cramps. Heat cramps
are very painful (envision someone stabbing a knife deep into your muscles!) and
rarely “work themselves out”. The cramps occur because you’ve lost minerals
through sweating and dehydration. Once you’ve reached the point of heat cramps,
it’s too late to try to replace fluids on the run. To make the cramps go away
- Stop running
- Drink fluids immediately. The fluids should include sports drinks as well as
- Massage the muscles once the pain begins to subside
- Cool your body with wet towels
- Get out of the sun
Heat exhaustion is a very serious condition that can lead to heatstroke. The
symptoms of heat exhaustion are:
- “Goose bumps” (particularly on the torso and arms)
- Nausea (sometimes accompanied by vomiting)
- Moderate to severe headache
- Weak legs
- Lack of coordination
- Rapid pulse
- Heavy sweating often accompanied by moist and cold skin
- Muscle cramping
If you experience any of these symptoms you must:
- Stop running immediately
- Get medical attention
- Drink large amounts of fluids, including sports drinks
- Get out of the sun
- Lie down and elevate your feet above your heart
- Loosen your clothing
Heatstroke can be fatal. Unfortunately runners will sometimes ignore the
symptoms of heat exhaustion (particularly in races longer than 10K) and will
continue to push themselves until they’re nearing a total thermoregulatory
breakdown. The symptoms of heatstroke are very similar to those of heat
exhaustion, but rapidly progress to:
- Weakness in the legs to the point that the runner may fall
- Strange behavior (including flailing with the arms and shoving)
- “Fuzzy” thinking
- Rapid pulse
- Cessation of sweating and hot/dry skin
- Body temperature that may reach 104 degrees or higher
- Lack of consciousness
- Convulsions or seizures
Someone suffering from heatstroke needs immediate medical attention. They should
be moved out of the sun, cooled by either rubbing their body with ice or
immersing them in cold water and given fluids intravenously.
Within the last few years the condition known as hyponatremia has begun to
attract the attention of sports medicine physicians, exercise physiologists, and
the medical directors at some of the larger marathons around the country.
Hyponatremia has been called water intoxication because of the symptoms it
produces. According to Dr. Tim Noakes, Professor of Exercise & Sports Science
Director at the University of Cape Town, “…a person with hyponatremia looks like
he or she is mildly drunk. They can’t concentrate normally…they forget what you
were talking about and start to concentrate elsewhere.”
Hyponatremia occurs when the body becomes dangerously low in sodium. It’s caused
when you literally take in too much water. Although scientists have known about
it for a long time, it has only been in the last few years as more runners have
been competing in marathons that it has become a concern. According to Dr.
Noakes, fluid has to be ingested at high levels for several hours for
hyponatremia to occur. He suggests that a runner would have to be drinking water
regularly for at least four to six hours to develop the condition. So runners
taking four to six hours or more to run a marathon are at particular risk.
Unfortunately, symptoms of hyponatremia tend to mimic those of severe
dehydration and/or heat exhaustion. By giving the athlete more water to drink
the hyponatremia becomes worse, as more and more sodium is flushed out of the
system. If a runner with hyponatremia is given fluids intravenously, they can
suffer a fatal reaction. Dr. Noakes and other sports medicine professionals
recommend that physicians and other medical personnel at road races be alert for
the signs of hyponatremia. One of the earliest symptoms is a craving for salty
Although hyponatremia is rare, it’s wise to be aware that it can occur,
particularly if you’re running a marathon in unusually hot weather. Hyponatremia
serves as a reminder that water is good, but don’t forget sports drinks, which
replenish your body with the sodium, potassium and other trace minerals you lose
through sweat. It’s worth repeating: if you’re going to be running (or racing)
for longer than an hour, you should be drinking a sports drink as well as water.
About the author:
Claudia Piepenburg has been running for 21 years and is the current editor for
Peak Run Performance. She holds or has held state age-group records in Michigan,
North Carolina, Florida, Tennessee and Virginia. In 1990, she was ranked 18th
fastest masters woman in the world and 8th fastest masters woman in the U.S. in
1990 and 1991. She competed in the 1988 Olympic Marathon Trials, was 20th woman
overall in the 1987 Boston Marathon and women's winner of the 1986 Virginia
Beach Marathon. If you have questions or comments for Claudia, she can be
reached at email@example.com.