Dehydration and hot weather

4 Signs You’re Getting Dehydrated During Deadly Heat Wave

Dehydration and hot weather

It’s just the start of summer, but already a record-breaking heat wave has parts of the country, with temperatures soaring to 120 degrees or more.

That is dangerously hot.

Extreme heat kills more people than hurricanes, floods, tornadoes and lightning combined, according to the National Weather Service. A heat wave is loosely defined as two or more days of excessively hot weather. But any prolonged period of temperatures greater than 90 degrees is risky because it taxes the body’s ability to maintain the safe internal temperature 98.6.

Drinking water is the most important thing to do during a heat wave.

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The rule of thumb is to drink at least two liters a day to stay hydrated. Do NOT wait until you feel thirsty. And avoid caffeine, alcohol and sugary drinks because they cause you to lose more body fluid.

Related: Triple digit heat wave kills four

Look out for these four subtle signs of dehydration during a heat wave:

Color of Urine: When your hydration status is good, your urine will be clear to light yellow. The darker the urine, the more dehydrated you are. Drink up when your pee is darker than usual.

The “pinch” test: When your body’s cells become depleted of water, the skin loses tension. Test the elasticity of your skin by pinching the back of your hand and hold it for a few seconds. Let go and if the little “tent” stays pinched and takes more than 5 seconds to go back to normal, it’s usually a sign of moderate dehydration.

Bad breath: Bad breath should make you think about dehydration during a heat wave. If you don’t drink enough water, and you’re losing water through sweating, your body can’t make enough saliva, meaning your mouth is dry and bacteria grow easily.

Sitting in front of a fan: New evidence has shown that when temperatures rise above 95 F, an electric fan might actually make you even hotter, by blowing hot air on you, making you unable to sweat.

And not being able to sweat puts you at greater risk of dehydration and even heat exhaustion. If possible, air-conditioning is the best choice. Cool showers and baths work, too.

Don’t forget your pets: Make sure they have enough fresh water to drink and limit their exercise. Keep in mind that the asphalt or other surfaces get extremely hot during a heatwave which could make it painful for them to walk on.

Related: Man breaks window of BMW to rescue dog in hot car

Also, watch out for water in garden hoses: it can become extremely hot and cause severe burns.

Felix Gussone, MD

Felix Gussone is an Associate Producer for NBC News, where he works for the Health & Medical Unit.

Samuel Sarmiento, MD

Samuel Sarmiento is a medical fellow for NBC News, where he works for the Health & Medical Unit. 

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How Do I Know If I’m Dehydrated? The Symptoms You Should Never Ignore

Dehydration and hot weather

It's hot outside — and it's about to get a lot hotter for millions of Americans this weekend. The National Weather Service has issued excessive heat watches, warnings and advisories in the Plains, Midwest and parts of the East Coast. More heat alerts are expected later this week, as temperatures in cities Chicago, Philadelphia and Washington, D.C. could reach 100 degrees.

What can you do to stay cool? Aside from staying indoors, in air conditioning, keeping your body well hydrated is key to staying healthy during a heat wave.

Heat can sometimes be very subtle in how it affects the body. If you're out in the sun, it can take just 30 minutes or up to a few hours for the heat to cause dehydration, nausea or trouble concentrating, said Dr. Corey Slovis, chairman of emergency medicine at Vanderbilt Medical Center.

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Dehydration is a serious health concern. A recent study published in the American Journal of Public Health found that more than half of all children and adolescents in the U.S. aren’t getting enough water.

“People don’t realize the amount of fluid they can lose in the heat, or while exercising,” explained Michael F. Bergeron, Ph.D., and president and chief executive officer of Youth Sports of the Americas. “And it’s important to note that your hydration needs are very individual,” said Bergeron.

This health issue is more serious than you might think and could land you in the hospital.

Heat stroke occurs when the body temperature gets above 105 degrees. “One of the earliest signs of a heat-related illness is just not feeling right,” said Slovis. “There's no one specific symptom.”

How much liquid do we need each day? It depends. Here are a few signs you might be dehydrated and tips to stay healthy all summer long.

1. Increased thirst and a dry or sticky mouth

“If you feel thirsty, you're already dehydrated,” explained Dr. Laura Goldberg of Cleveland Clinic Sports Health. The easiest remedy is to start drinking water (and beverages with electrolytes) as soon as you notice this, but try not to let yourself get to this point.

The best way to prevent this from happening is to meet your daily hydration needs, for women, the National Academy of Sciences recommends 2.7 liters of water a day (about 11.4 cups), and for men, 3.7 liters (15 cups). Try to drink more water if you've spent excessive time in the sun, or exercising.

2. Signs of fatigue, confusion or anger

Studies have found that mild levels of dehydration can affect your mood and cognitive functions. This is especially common in the young or elderly, who may seem less alert, or forgetful.

A study from the University of Connecticut Human Performance Laboratory found that even mild dehydration can alter a person mood, energy and ability to think clearly. The researchers defined mild dehydration as an approximately 1.5% loss in normal water volume in the body — and the adverse reaction is the same whether you're exercising or sitting still.

3. Dry eyes or blurred vision

“When you've been exercising for a long time, you're sweating and your overall body fluid goes down — this can result in dry eyes or blurred vision,” said Goldberg, who also noted that any part of the body that is normally moist is going to feel dry or irritated.

“Monitor your hydration levels and make sure you're drinking throughout any form of exercise,” she explained further.

4. Headaches or disorientation

Dehydration can result in a headache or migraine, light headedness or delirium. “I’ve seen marathon runners running in zigzags because they’re dehydrated. You can’t make decisions and feel delirious,” elaborated Goldberg.

“You may also experience weakness, dizziness, or nausea, because the body doesn’t have enough fluid to send to other parts of the body. This could also result in heat exhaustion. You can collapse if you don’t stop exercising and cool down,” warned Bergeron, who also added that these specific symptoms can also be signs of over hydration, so be aware of how much you’re drinking.

5. Muscle cramps

“If you’ve been exercising, it’s natural for your legs to feel tired, but if it’s more than that and you’re experiencing muscle cramping, that’s a serious sign of dehydration,” Goldberg explained. This is because of the loss of water and salt in the body — you also might experience tightness in your muscles, instead of cramping.

“Wandering and progressively widespread muscle cramping is a certain clue of a sodium deficit and dehydration in the fluid spaces surrounding certain muscles,” Bergeron elaborated. “But don’t confuse it with an overworked muscle which would just affect a small area.”

To prevent this from occurring, it’s important to drink sports beverages that contain sodium, or snack on salted pretzels or low-fat cheeses. The sodium helps your body to re-hydrate and retain the water.

6. Lack of sweat

According to Goldberg, this is one of the more serious signs of dehydration. It means your body is in dire need of water. Though, on the other hand, Bergeron notes that more ly it may be a sign of overheating or heat stroke — though either can occur in the presence of continued sweating. Either way, it’s crucial to cool down rapidly if you’re not sweating anymore.

7. Dark urine 

“Straw-colored or light yellow urine means you're properly hydrated. If your urine is dark, or if there’s blood in your pee, you need to stop exercising immediately,” warned Goldberg. Notably, perfectly clear urine may mean that you are over-hydrated.

8. Fever

“Dehydration can lead to hyperthermia and a fever- symptoms (e.g. chills) because over-heating can alter your body's normal temperature 'set point,'” explained Goldberg. Excessive overheating is an urgent red flag. Stop exercising immediately, take an ice bath and hydrate.

9. Shriveled and dry skin

If  your skin is hydrated, it will appear doughy. If you’re dehydrated, your skin will lack elasticity and won’t bounce back. “If you pinch your skin and it appears thin and doesn’t melt back onto your body quickly, you’re dehydrated,” said Goldberg.

Some key things to remember when exercising in the summer is that the longer you’re working out, the more water you need. Also, plain water is good for you, but a combination of water, electrolytes and sodium is really the best way to stay hydrated.

It’s also crucial to understand that hydrating properly isn’t 100% preventative, if you’re working too hard and too long in the summer heat, you can still overheat no matter how much water your drinking. So be aware of your body, and stop what you’re doing if you notice any of these symptoms.

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Dehydration and Heat Stroke

Dehydration and hot weather

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Dehydration and heat stroke are two very common heat-related diseases that can be life-threatening if left untreated.

What is dehydration?

Dehydration can be a serious heat-related disease. It is also a dangerous side effect of diarrhea, vomiting, and fever. Children and people over the age of 60 are particularly susceptible to dehydration.

What causes dehydration?

Under normal conditions, we all lose body water daily through sweat, tears, breathing, urine, and stool. In a healthy person, this water is replaced by drinking fluids and eating foods that contain water.

When a person becomes so sick with fever, diarrhea, or vomiting, dehydration happens. It also happens if an individual is overexposed to the sun and not drinking enough water.

This is caused when the body loses water content and essential body salts, such as sodium and potassium.

Occasionally, dehydration can be caused by medicines, such as diuretics. These deplete body fluids and electrolytes. Whatever the cause, dehydration should be treated as soon as possible.

What are the symptoms of dehydration?

The following are the most common symptoms of dehydration. However, each individual may experience symptoms differently. Symptoms may include:

  • Thirst
  • Less-frequent urination
  • Dry skin
  • Fatigue
  • Light-headedness
  • Dizziness
  • Confusion
  • Dry mouth and mucous membranes
  • Increased heart rate and breathing

In children, additional symptoms may include:

  • Dry mouth and tongue
  • No tears when crying
  • No wet diapers for several hours
  • Sunken abdomen, eyes, or cheeks
  • Listlessness
  • Irritability
  • Skin that does not flatten when pinched and released

The symptoms of dehydration may resemble other medical conditions or problems. Always talk with your healthcare provider for a diagnosis.

Treatment for dehydration

If caught early, dehydration can often be treated at home under a healthcare provider's guidance. In children, directions for giving food and fluids will differ according to the cause of the dehydration, so it is important to talk with your child's healthcare provider.

In cases of mild dehydration, simple rehydration is recommended by drinking fluids. Many sports drinks on the market effectively restore body fluids, electrolytes, and salt balance.

For moderate dehydration, intravenous (IV) fluids may be needed. If caught early enough, simple rehydration may be effective. Cases of serious dehydration should be treated as a medical emergency, and hospitalization, along with intravenous fluids, is necessary. Immediate action should be taken.

How can dehydration be prevented?

Take precautionary measures to avoid the harmful effects of dehydration, including the following:

  • Drink plenty of fluids, especially when working or playing in the sun.
  • Make sure you are taking in more fluid than you are losing.
  • Try to schedule physical outdoor activities for the cooler parts of the day.
  • Drink appropriate sports drinks to help maintain electrolyte balance.
  • For infants and young children, solutions such as Pedialyte will help maintain electrolyte balance during illness or heat exposure. Do not try to make fluid and salt solutions at home for children.

What is heat stroke?

Heat stroke is the most severe form of heat illness and is a life-threatening emergency. It is the result of long, extreme exposure to the sun. In this case, a person does not sweat enough to lower body temperature.

The elderly, infants, persons who work outdoors, people with mental illness, obesity, poor circulation, and those on certain types of medicines or drinking alcohol are most susceptible to heat stroke.

It is a condition that develops rapidly and needs immediate medical treatment.

What causes heat stroke?

Our bodies make a tremendous amount of internal heat and we normally cool ourselves by sweating and radiating heat through the skin. However, in certain circumstances, such as extreme heat, high humidity, or vigorous activity in the hot sun, this cooling system may begin to fail. This allows heat to build up to dangerous levels.

If a person becomes dehydrated and cannot sweat enough to cool his or her body, his or her internal temperature may rise to dangerously high levels. This causes heat stroke.

What are the symptoms of heat stroke?

The following are the most common symptoms of heat stroke. However, each individual may experience symptoms differently. Symptoms may include:

  • Headache
  • Dizziness
  • Disorientation, agitation, or confusion
  • Sluggishness or fatigue
  • Seizure
  • Hot, dry skin that is flushed but not sweaty
  • A high body temperature
  • Loss of consciousness
  • Rapid heartbeat
  • Hallucinations

The symptoms of a heat stroke may resemble other medical conditions or problems. Always talk with your healthcare provider for a diagnosis.

Heat-related illness is a serious concern for everyone who is exercising during extreme summer heat. Most at risk: young athletes who may not know when to take a break and cool down. Johns Hopkins primary care and sports medicine expert Dr. Raj Deu explains what parents can do to help prevent their children from experiencing heat-related illness.

It is important for the person to be treated immediately as heat stroke can cause permanent damage or death. There are some immediate first-aid measures you can take while waiting for help to arrive, including the following:

  • Get the person to a shaded area. 
  • Remove clothing and gently apply cool water to the skin followed by fanning to stimulate sweating.
  • Apply ice packs to the groin and armpits.
  • Have the person lie down in a cool area with their feet slightly elevated.
  • Cool the person rapidly however you can.

Intravenous (IV) fluids are often necessary to compensate for fluid or electrolyte loss. Bed rest is generally advised and body temperature may fluctuate abnormally for weeks after heat stroke.

How can heat stroke be prevented?

There are precautions that can help protect you against the adverse effects of heat stroke. These include the following:

  • Drink plenty of fluids during outdoor activities, especially on hot days. Water and sports drinks are the drinks of choice. Avoid caffeinated tea, coffee, soda, and alcohol, as these can lead to dehydration.
  • Wear lightweight, tightly woven, loose-fitting clothing in light colors.
  • Schedule vigorous activity and sports for cooler times of the day.
  • Protect yourself from the sun by wearing a hat, sunglasses and using an umbrella.
  • Increase time spent outdoors gradually to get your body used to the heat.
  • During outdoor activities, take drink breaks often and mist yourself with a spray bottle to avoid becoming overheated.
  • Try to spend as much time indoors as possible on very hot and humid days.
  • Never leave children or pets in closed cars on warm or sunny days. 

If you live in a hot climate and have a chronic condition, talk to your healthcare provider about extra precautions you can take to protect yourself against heat stroke.

#TomorrowsDiscoveries: Imbalances of salt and water in the body can lead to problems ranging from cystic fibrosis to diarrhea to kidney failure. Dr. Guggino and his team study the channels that move salt and water– and what goes wrong with them in disease.


3 Ideas for Avoiding Dehydration in the Summer Heat

Dehydration and hot weather

It’s only May, but the summer heat waves have started early. Warmer-than-usual weather and record-setting heat has hit California. Texas. Central Florida. The High Plains. And overseas in Great Britain and Australia. If that’s any evidence, we may be in for a warmer-than-usual summer.

When the temperature rises, unfortunately, so too does the risk for developing dehydration. Essentially, the weather gets hotter causes your body temperature to rise, and to cool yourself, you sweat more. This loss of fluid through sweat, which happens faster if you haven’t had a chance to acclimate, can cause dehydration.

But dehydration isn’t the sole concern for those who work, play and exercise outdoors in hot weather. In fact, more serious conditions heat illness and exhaustion can are exacerbated by the heat and dehydration. Not to mention, both of these conditions can lead to heat stroke, one of the most dangerous warm-weather-related illness.

Strategies to Prevent Dehydration in Hot Weather

Dehydration is a common cause of heat exhaustion, because when you’re dehydrated, your body doesn’t sweat enough or fast enough to dissipate heat. Therefore, preventing dehydration is one of the most effective strategies to avoid heat exhaustion in the summer. Here are a few tips:

1. Acclimation: Early in the summer, or a week or more before doing intensive activity in the heat (say before the start of a sports season), it’s important to let your body acclimate to the heat.

If possible, allow time to exercise outside for shortened periods, then increasing the length of time you spend outdoors leading to the start of the season, or before a long hike or whatever reason you’ll be outdoors.

For those who don’t have the luxury to properly acclimate — say a mail carrier or construction worker —  the initial heat wave is ly to make you you a sweat more. Therefore, a carbohydrate-electrolyte drink DripDrop is recommended to help you replace fluids, electrolytes and retain water.

2. Proper Hydration: Drinking enough fluids is important to prevent dehydration, but what does that mean exactly? An effective strategy is to drink before, during and after exercising or working in the heat.

Your fluid requirements will depend on a variety of factors, but a standard hydration plan includes 15-20 fluid ounces of water 2-3 hours before exercise; 8-10 fluid oz. 20 minutes before; and up to 10 fluid oz. every 15 minutes during exercise. Following exercise or work outdoors, drinking 20-24 fluid ounces of fluids for every pound lost is essential for rehydration.

Plus, an electrolyte-carbohydrate drink DripDrop may be necessary during intense workouts that last longer than an hour or an hour and a half.

3. Avoid Hottest Parts of the Day: If possible, avoiding hot weather, of course, can be a big help. Or if you’re planning on being outdoors working or exercising, try to schedule around peak heat  hours in the afternoon.

During the high-heat of summer, DripDrop is the perfect addition to your water bottle. Extended periods in the heat, whether for work, play or exercise, require more than just water. The solution is simple — drink DripDrop.

Image via Flickr.


Staying Hydrated During the Hot Summer Weather

Dehydration and hot weather

Stay safe and performing at your best this summer with these hydration tips! Whether you’re doing high intensity training or simply enjoying the outdoors on a hike or a run, it is important to stay hydrated, especially when the mercury rises during the summer months.

Water is the basis for life. It is second only to oxygen in importance for health, making up to 75% of the body. Although water does not provide a source of calories, adequate hydration is at least as important to good athletic performance as the food you eat and is essential for efficient training, playing and racing.

Proper hydration not only quenches one's thirst but allows the body to flush toxins, maintain system equilibrium (balance), support brain function, hormone balance, metabolic processes (including fat metabolism), the  transportation of life-giving vitamins and minerals, and supports the integrity of muscle, joint and bone in our bodies.

Although the human body can, in extreme cases, go without food for up to six weeks, it can only survive a week without water.

As a general rule, it is recommended that the average person consume at least eight, 8-ounce servings of water each day (2 litres a day). The more time you spend outdoors and the more active you are, the more water you need to replenish lost fluids.

Replenishing fluids is especially important when exercising in hot and humid weather conditions as your body tends to sweat more.

Tips for Proper Hydration:

  • Start and end your day with a 250 ml serving of water. Your body loses water while you sleep, so drink a serving before bed and again when you wake up.
  • Drink before you are thirsty. By the time you feel thirsty; you have probably already lost two or more cups of your total body water composition. Drink plenty of water throughout the day. Carry a bottle of water with you daily. Keep a bottle of water on your desk and refill at the office water cooler regularly.
  • Don't substitute with alcoholic beverages. Alcohol is a diuretic and will cause you to lose water through increased urination.
  • It’s important to note that although coffee and tea do have a diuretic effect, they do provide a significant amount of fluid and any effect of caffeine on urine losses are minor (especially for habitual caffeine users).
  • Keep drinking water even when it is cold outside. You may not feel thirsty as you do when it's hot, but you are still going to lose water through perspiration. You also lose fluids through exhaled air. When cold, dry air is inhaled, it is warmed and moistened in the lungs and exhaled as humid warm air. This process makes intense demands on the body's water supply.
  • Average sweat rates can vary from 0.5L/hour to more than 2.5L/hour. Knowing your sweat rate will help you to better prepare for both training and competition. Calculate your sweat rate. Taking the time to calculate how much you sweat is a fundamental consideration for optimal hydration.

Hydration Prior to Exercise
Begin all workouts well hydrated. Drink 450-650 ml of water or sports drink 1 to 3 hours before exercise. Consuming an additional 200-300 ml 10-20 minutes prior to the training session is also good practice.

Hydration During Exercise

Drink 200-350 ml every 15-20 minutes. If possible, given your sporting activity, take regular 'sips' throughout the activity.

For longer training sessions (or in hot weather) consider using a sports drink as part of your hydration regimen (prior to, during and following activity).

The sodium and potassium content in most sports drinks will permit you to maintain a proper electrolyte balance.

Hydration Following Activity

Drink 500-1000ml within 1 hour, post exercise. You should aim to 'push' fluid intake even if you don't feel thirsty. Given that you will eliminate some fluid through urination, you’ll want to drink more than what you've lost.

How can I tell when I'm dehydrated?

One of the easiest ways to tell whether you are adequately hydrated is by checking the colour of your urine. In general, light coloured urine is an indication of adequate hydration. If you are experiencing infrequent urination and the colour of the urine is dark yellow, these are signs of dehydration.

Other signs of dehydration are: thirst, headache, constipation, fatigue, weakness, dizziness, irritability, cramps, depression, weight, gain, water retention, skin blemishes, vomiting or nausea, and bladder infections.

Can I drink too much?

Absolutely! While many athletes understand the importance of proper hydration, most do not realize that overhydrating can dangerously lower blood sodium levels; a condition known as hyponatremia or “water intoxication.”

Everyone responds to exercise differently. Ultimately, hydration is not simply a question of drinking fluids. It’s about knowing your own body and drinking the right fluids for you and the various activities you participate in, preparing accordingly for various environmental conditions — especially the heat.


Tips on staying hydrated during hot, humid weather

Dehydration and hot weather

We are now settling into what is typically the hottest time of the year. As temperatures rise, it is important to not only stay cool, but also to drink plenty of fluids to avoid dehydration. 

More than 70 percent of the human body is made of water. Fluids keep our organs running, cushion our joints and make sure oxygen is getting to the body’s cells. Dehydration happens when a body does not have enough fluids to perform those essential functions. While people can become dehydrated due to illness, I want to focus on how the body reacts during hot, humid weather.

People working or exercising outside when the temperatures rise are the most at risk of becoming dehydrated or suffering from another heat-related illness. When the air is humid, sweat cannot evaporate as easily from your skin. Sweat cools your body and when you are unable to sweat, your body temperature rises. That combination means your body needs even more fluid to function properly.

The most common signs of dehydration are extreme thirst, fatigue, dizziness and less frequent urination. Some people get headaches or feel nauseous. Anyone can become dehydrated, but young children and older adults are most at risk. 

When left untreated, dehydration can lead to heat exhaustion, cramps and seizures, which can cause you to lose consciousness. Mild dehydration can easily be reversed by drinking more fluids, but severe dehydration requires immediate medical treatment. When someone is severely dehydrated, she may need to go to the hospital to receive salts and fluids intravenously to recover.

So how can you avoid becoming dehydrated as temperatures increase?

Drink lots of cool water. You can also try a sports drink with electrolytes if you sweat excessively.

Take breaks. This sounds common sense, but it is important. If you are working outside, make sure you take a short break every hour or more often if needed. Seek out shade and air conditioning if possible.

Dress appropriately. Three tips to help you dress “cooler:” Opt for sweat-wicking clothing, which keeps you cool; wear light-colored clothing, which reflects sunlight; and loose clothing which allows air to reach your skin and keeps you cooler.

Avoid being outside during the middle of the day. Temperatures tend to be at their highest between 10 a.m. to 2 p.m. so that is a good time to stay inside. If you exercise outside, go early in the morning or in the evening, when the sun is less intense and temperatures are cooler. 

Don’t drink alcohol or beverages with caffeine. Alcohol and caffeine are both diuretics, which means you will become dehydrated more quickly. If you do want to enjoy a beer or another alcohol drink, be sure to drink water afterwards to decrease the chances of becoming dehydrated.

You can avoid dehydration during the hot summer months by drinking lots of water and being careful to not overexert yourself. Staying hydrated will help you feel better and keep you healthier.

Scott Schuldes is a certified family nurse practitioner at ThedaCare Physicians-Hilbert and ThedaCare Physicians-Darboy. He can be reached at

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Tips to Stay Cool and Prevent Dehydration

Dehydration and hot weather

Marc Romanelli/Blend Images/Getty Images

Summertime is time to think about preventing dehydration and heat-related illness. Did you know that about 618 Americans die every year of heat-related illnesses, according to the Centers for Disease Control? The sad fact is that most of these deaths could have been prevented, had the victims understood the realities of dehydration and heat-related illness more clearly.

Regularly exercising, which is often done outdoors, is just as important during the hot months of summer as it is during the cooler seasons.

Unfortunately, outdoor activities often place people at a more serious risk of dehydration, which can lead to other heat-related illnesses including, heat exhaustion, heat stroke and in severe cases, death.

Millions of Americans are at risk for heat-related illnesses, but the risk is significantly increased for four segments of our population. Those most at risk include:

  • Children. When summer vacation from school arrives, most children spend a great deal of time outdoors being active. Because children have a larger surface area in relation to body mass, they often gain heat faster than adults when the outside air temperature is higher than body temperature.
  • Athletes and exercisers. People who spend hours training and competing in the hot summer sun often do not have an adequate intake of fluids to make up for the loss of fluids caused by their activities.
  • Outdoor workers. Workers such as landscapers, construction crews, police officers, postal employees and others who spend most of their days in the heat often have little time for bathroom breaks or for drinking fluids. As a result, these workers may not consume enough fluids during their workdays.
  • Elderly people. There is a fine line between how heat affects most adults and how it affects the elderly in more profound ways. It's extremely important for senior citizens to practice a gradual acclimatization to heat that puts an emphasis on hydration.

You might be thinking: “But I'm used to the heat. It doesn't affect me.” That statement may seem common sense, but nothing could be further from the truth when it comes to heat-related illness and dehydration.

According to Dr. Noel D. Nequin, president of the American Medical Athletic Association, “Being 'used to' the heat or 'acclimatized' is necessary for the body to perform in hot, humid conditions without overheating. But acclimatization increases your need for fluid to match the increase in sweat rate, which puts you at higher risk for dehydration and heat illness.”

So how does one acclimatize their body to heat? It takes about 10 to 14 days of working or exercising in the heat for your body to adjust or become acclimatized.

You should cut down on the intensity of your exercise or activity during these first days.

 Once your body is heat acclimatized, the amount of sweat you produce and other total body fluid losses increases because you sweat sooner and more than before you became acclimatized.

The good news about summer heat is that staying healthy is as easy as becoming educated about your body's need for fluids, and the signs and symptoms of dehydration that can lead to heat-related illnesses such as heat stroke and heat exhaustion.

During higher intensity or longer periods of exercise, the best time to consume fluids is before you are thirsty. By the time you are thirsty, your body is already dehydrated. It's best to drink on a schedule when it is hot outside.

Avoid drinks that contain caffeine or alcohol while in the sun or heat. These types of drinks stimulate the production of urine, thereby promoting dehydration. The best drink is water.

You could also opt for one of the many flavored sports drinks that are on the market.

According to Dr. Nequin, “Research clearly shows that a properly formulated sports drink Gatorade combines flavor and sodium to encourage people to drink more than they would when they only have access to water. Sports drinks help to replace some of the electrolytes you lose through sweat and provide carbohydrate energy to working muscles.”

Water is a necessity that the human body requires to stay healthy. If you fail to drink enough daily water or other non-caffeinated fluids, you may experience a heat-related illness such as dehydration. But how much water is necessary in order to stay hydrated and prevent dehydration or other heat-related illnesses?

Adults need 17 to 20 ounces of fluid before beginning activity as well as an additional 7 to 10 ounces every 10 to 20 minutes during activity. Your fluid needs don't stop when your activity is over: you should consume 24 ounces of fluid within the first 2 hours after outdoor activity.

Children need 4 to 8 ounces of fluid before beginning outdoor activities, and 5 to 9 ounces every 20 minutes while they are outside. Once kids return from outside play or activity, they also need to consume 24 ounces of fluids within the first 2 hours after they stopped their activities.

Did you know? One adult-sized gulp of fluid equals one ounce of fluid, and one child-size gulp of fluid equals one-half ounce of fluid.

Dehydration is 100 percent preventable. You can typically treat mild to moderate dehydration yourself by drinking more fluids or a sports drink. Mild symptoms of dehydration include:

  • Dry lips and tongue
  • Dry, sticky mouth
  • Headache
  • Weakness, dizziness, or extreme fatigue
  • Concentrated urine that appears darker than normal
  • Nausea

As previously mentioned, these are mild symptoms that can be treated yourself, but only if you are a healthy adult. If a child or elderly person displays any of the above symptoms, call your doctor immediately. You should also seek immediate medical attention if you or someone you love exhibits the following severe symptoms of dehydration:

  • Severe diarrhea or moderate diarrhea for 24 hours or more
  • Bloody or black stool
  • Inability to keep fluids down
  • Appears disoriented, is irritable or has extreme fatigue
  • Little to no urination
  • Very dry mouth, skin, and mucous membranes
  • Rapid breathing or heart rate
  • Sunken eyes

Drinking water is the best thing you can do to stay hydrated, but there are a few other things you can do to prevent dehydration. Wear light-colored and loose-fitting clothing to stay cool.

 Whenever you get a chance, take a break in the shade.

It's important to remember that anytime a person who has been exposed to heat becomes disoriented or unconscious, immediate medical attention for that person must be sought.

You may be familiar with a few concepts that are actually incorrectly believed to keep you cool. Take pouring water over your head, for example. It might feel good, but it actually has no effect on your core body temperature.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

  1. Centers for Disease Control and Prevention. About Extreme Heat. Updated June 19, 2017.

  2. Daanen HAM, Racinais S, Périard JD. Heat Acclimation Decay and Re-Induction: A Systematic Review and Meta-Analysis. Sports Med. 2018;48(2):409-430. doi:10.1007/s40279-017-0808-x

  3. Périard JD, Racinais S, Sawka MN. Adaptations and mechanisms of human heat acclimation: Applications for competitive athletes and sports. Scand J Med Sci Sports. 2015;25 Suppl 1:20-38. doi:10.1111/sms.12408

  4. Kenefick RW. Drinking Strategies: Planned Drinking Versus Drinking to Thirst. Sports Med. 2018;48(Suppl 1):31-37. doi:10.1007/s40279-017-0844-6

  5. France RC. Introduction to Sports Medicine and Athletic Training. 2nd edition. Clifton Park, NY: Cengage Learning; 2010.

  6. NHS Inform. Dehydration. Updated February 14, 2020.

Additional Reading

  • Kari Volyn, Kari. Beat the Heat: AMAA Warns About Dangers of Heat Illness. The American Medical Athletic Association. 15 June 2002.


Why You Should Stay Hydrated During the Heat

Dehydration and hot weather

Jupiter Images / Getty Images

When you spend time outside in hot weather you probably start to feel thirsty in a fairly short time. That's a normal response and one you should pay close attention to—it means your body needs more water to deal with the heat. Learn why this happens, the symptoms of dehydration, and how to ensure you are drinking enough water when the temperatures rise.

Your body functions best within a certain temperature range, and when you get too warm, it needs to cool off. There are a couple of ways your body accomplishes this cooldown. First, your blood vessels dilate to increase blood flow to the skin.

This allows excess heat to radiate away from your body. Then, you also start to sweat. Evaporation of the sweat cools the skin, which in turn helps to cool the whole body. But, the problem is that excessive sweating can lead to dehydration.

You sweat more when the temperature's hot, especially if you're working or exercising in the heat. Drinking water helps replenish the fluids lost by excessive sweating. If you don't get enough water, you may become dehydrated, and the combination of hot temperatures and dehydration can lead to serious heat-related illnesses.

For most people, thirst is a very good indication that you need more water. Even before you become dehydrated, you'll feel thirsty, and your mouth may feel dry or sticky.

After a while, you may also become lethargic and fuzzy-headed. Other signs include reduced urine output (and the urine is dark yellow). You might even notice your eyes look a bit sunken and feel dry.

Even a little dehydration can be a problem, so don't ignore those early signs. Even mild dehydration reduces your ability to think clearly and your physical coordination.

  • Start hydrating right away. It's easier to maintain your fluid balance if you start out in a well-hydrated state.
  • Schedule regular beverage breaks and keep a water bottle handy so you can take frequent sips of water while you work or exercise.
  • Choose electrolyte-replacing drinks for maximum water absorption when you are exercising for more than an hour or when you are sweating excessively during exercise in hot weather.
  • Drink water after you've finished work or an exercise session.
  • Snack on fresh fruits that are rich in water, berries, watermelon, peaches, and nectarines.
  • Don't drink large amounts of plain water all at once—this can lead to ​hyponatremia or water-toxicity. This can also affect long-distance runners during races who push too many fluids.

    It is best to drink when thirsty during exercise and not push fluids.​​

One way to gauge your hydration level is to look at the color of your urine. If you're well-hydrated, it should be pale. Also, you'll be urinating more frequently.

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Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

  • Dehydration. United States National Library of Medicine MedLine Plus.

  • Miller VS, Bates GP. Hydration, Hydration, Hydration. The Annals of Occupational Hygiene. 2009. doi:10.1093/annhyg/mep091.