By Denise Mann, / Reviewed by Matthew Hoffman, MD
Quench your thirst safely this summer and avoid dehydration. As a seasoned marathon runner, 36-year-old Jeri Salazar has her hydration needs down to a science. And well she should. In addition to being an executive at Disney, this Irvine, California, resident is also the Team in Training Marathon Coach for South Orange County and often preaches what she practices to a group of novice runners.
“I drink 64 ounces of water each and every day so I’m always in a well-hydrated state,” she tells WebMD. In two days before the recent Boston Marathon, she included a sports drink replete with electrolytes as part her daily fluid diet. “I figured that getting the extra sodium and potassium in my system couldn’t hurt, especially considering what a “salty” sweater I am,” she says.
Turns out, that was a good call at this year’s Boston marathon. An unusually large number of runners were treated for dehydration because the temperature reached 72 degrees. Fortunately, Salazar was not one of them.
But alas, dehydation is not the only problem that athletes may acquire. Too much water can cause a condition called hyponatremia which means that your sodium levels are too low. That’s why it’s crucial for athletes to strike the proper balance when it comes to hydration. Whether you’re a marathon runner like Salazar or a weekend warrior, knowing precisely how much fluid to consume before, during, and after workouts — especially in the heat of the summer – can help stave off both conditions.
Hydration in the heat
“Staying hydrated is fundamentally important to a successful summer exercise regimen, in fact, for any activity,” says Survivor consultant Adrian Cohen, MD, of Neutral Bay, Australia. As the medical advisor for many reality shows, including Survivor and Eco Challenge, Cohen has seen firsthand the havoc that dehydration can wreak on performers and performance. “While we tend to focus on hard, sweaty workouts and long jogging sessions, even a brisk walk or a scratch basketball game in the hotter weather puts demands on the human body, and without the ‘fuel’ [water] the engine runs dry,” says Cohen, author of several books, including Survivor First Aid. Successful, balanced hydration starts with prepping yourself for exercising in the heat, says New York City- based sports medicine expert Lewis G. Maharam, MD. “Take 10 days to two weeks to get used to hot weather, building workout intensity and duration gradually,” he says. Engage in higher-intensity activities during cooler morning hours and do easier work during the heat of the afternoon, he suggests.
Choosing your hydration fluid
If you are not running a race, “the rule of thumb is to drink 8 ounces of a sport drink or water possibly every 20 minutes,” says Maharam, who advises the ING New York Marathon. No more, no less. If you are exercising less than 40 minutes, water is fine, but for anything over 40 minutes, you want a sports drink that has sugar or salt in it because this helps you increase the fluid that goes into the body. Most sports drinks contain the equivalent of an “active pump” that gets more water into the body faster than the unassisted process—simple diffusion of water—would have.
When choosing a sports drink, look for salt and sugar on the label and choose a flavor that you like. While shoppers may be bombarded with vitamin-infused beverages, Maharam says added vitamins are useful for recovery and post-event muscle soreness—not for hydration the day of the event.
It’s also important to replace the fluid you lose during exercise, he says. Weigh yourself right before and after workouts and for every pound lost, drink 8 ounces of fluid.
Moreover, “step out of bed every morning and onto the scale, and if you’re anywhere from 1 percent to 3 percent lighter than yesterday, rehydrate by drinking 8 ounces of fluid for each pound lost before training again,” he says. “If you are between 3 percent and 6 percent lighter, rehydrate and back off that day’s training intensity. And if you lost over 7 percent, get to the doctor.” Dehydration is somewhat insidious, Cohen adds. You can’t always tell when it’s starting.
“Humans don’t have a ‘fuel gauge’ like your car, so there is no way to tell if you’re full or even approaching empty, and thirst is typically a poor guide,” he says. Early signs of dehydration may include poor concentration, headache and inability to think clearly.
“Most people are chronically dehydrated as it is,” says Eric von Frohlich, a group exercise instructor at Equinox in New York City and the chief exercise officer of Roadfit, an outdoor training group fitness organization. “Drink before your thirst kicks in,” he says, touting the benefits of prehydration. “Drink 16 ounces before an event or session so have some extra fluid. You don’t want to suck down two glasses of water and bolt out the door for a run.” So wait about two hours before engaging in your activity of choice.
How much?
We’ve heard for years that we need to drink eight, 8-ounce glasses of water a day. Before you start chugging, is it true?
“There is no scientific evidence whatsoever for that rule,” says Kenney. “It’s certainly not a harmful rule, but there is no scientific rationale behind it.” Instead, it’s pretty simple: For the average person, drink enough so you go to the bathroom every two to four hours. “You should be drinking enough so that you urinate every two to four hours, and that the urine is a light color,” says Clark, author of Nancy Clark’s Sports Nutrition Guidebook. “If you go from 8 a.m. till 3 p.m., and your urine is very dark, that’s a sign that you haven’t had enough to drink.”
Most of us do a pretty good job of getting adequate amounts of fluids as part of our everyday routines: coffee in the morning, soda or juice with lunch, a glass of water in the afternoon, and water with dinner. Coupled with the water that makes up our food, usually, this is sufficient.
Athletes, of course, need more
“The exact amount of water needed per day really depends on the individual,” says Rick Hall, a registered dietitian in Phoenix. “People who exercise, for example, will lose a lot more water through sweat and breathing, so their needs are higher.”
Athletes need to quench their thirst even when they’re not thirsty, and avoid relying on the feeling of thirst to tell them when to drink.
“Headaches and cramping are common signs of dehydration,” says Hall. “However, these are late signs. Unfortunately, the body hides mild dehydration very well, and it can take hours before you recognize that you are dehydrated.”
Exercise, explains Hall, blunts the thirst mechanism.
“So folks who are running or biking may not feel thirsty when they actually need water desperately,” Hall tells WebMD. www.webmd.com
“An important strategy is to prevent dehydration by hydrating frequently.”
Too much of a good thing
We know we need to drink fluids to maintain a healthy body, but is there such as a thing as too much?
There is a lot of information out there now about hyponatremia (low sodium levels), which is much rarer than dehydration problems, but it can still be a concern, says Kenney.
According to the ACSM web site, “While hyponatremia is a rare occurrence, it is a dangerous condition that may arise when athletes drink too much water, diluting the body’s sodium levels. It is most often seen in prolonged endurance athletes, such as those participating in marathons and triathlons.”
To strike a balance between too much and too little fluid intake, Kenney recommends weighing yourself before and after exercise, and drinking enough to replace the amount ofweight you lose. If you’re gaining weight, you know you’re drinking too many fluids, and if you’re losing weight, you know you need to drink more.
Water takes the cake
So we know we need fluids, we know the eight 8-ounce rule isn’t backed by science, and we know that we need to strike a balance between too much and too little intake. We also know that almost any fluid will add value to our bodies, but water takes the blue ribbon.
“The body needs water for millions of metabolic processes, temperature control, fluid volume, and lubrication,” says Hall. “But many health-conscious folks drink water often because it is a calorie-free thirst quencher. Some research shows that drinking water often may help to suppress the appetite and it certainly aids in digestion.”
Water, or any fluid that we drink, is something most of us take for granted. For Debbie Kiley, that’s not so.
“There aren’t many things I would sell my soul to the devil for, but when I was out on that raft, fresh water was one of them,” says Kiley. “I do not take water for granted, that’s for sure. It’s one of those things in life that seems so available, but when it’s not there it’s a real bummer.”
To say the least.
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