On hot days, the body really needs water, but the advice "just drink more" is not always enough. During extreme heat, working outdoors, playing sports, illness, vomiting, diarrhea, or profuse sweating, a person loses not only fluid, but also electrolytes - primarily sodium, potassium, and other minerals that are involved in the functioning of the nervous system, muscles, and maintaining water balance.
For most healthy people, water should be their main drink on a typical day. But if you are in the heat for a long time, are actively moving, sweat a lot, or have symptoms of dehydration, your body may need not only fluids but also salts. For work or activity in hot conditions, it is recommended to drink water regularly, and if sweating for several hours, use drinks with balanced electrolytes; it is better to limit alcohol and drinks with a high caffeine or sugar content.
This material explains what to drink in the heat, when you need mineral water or a rehydration solution, whether coffee and tea are okay, which foods help maintain hydration, and when you should not "endure the heat" but seek medical attention.
Why water doesn't always save you in the heat
When you overheat, your body cools itself by sweating. Water is lost with sweat, but salts are also lost. If a person simply drinks a lot of water but sweats for hours, works out or plays sports, they can partially replace their fluid volume, but not fully compensate for the electrolyte losses.
This doesn’t mean that water is “bad.” In fact, in most everyday situations, it’s the best basic beverage. Drinking water on hot days helps you stay hydrated, regardless of your activity level.
The problem starts when the situation becomes more intense: several hours of work in the sun, a long walk in +35°C, exercise, a road without air conditioning, fever, vomiting or diarrhea. In such conditions, simply “rehydrating” may not be enough: small regular portions of fluid, coolness, rest, food with minerals or a special rehydration solution are needed.
How much fluid should you drink daily?
There is no one-size-fits-all number. Fluid needs depend on weight, age, temperature, physical activity, diet, health status, pregnancy, breastfeeding, medication, and kidney function.
A guideline for healthy adults in temperate climates is about 15.5 cups, or 3.7 liters, of total fluids per day for men, and 11.5 cups, or 2.7 liters, for women. It's important to note that this isn't just pure water: some of the fluid comes from food and other beverages.
The Harvard TH Chan School of Public Health also explains that water is needed to replace losses through metabolism, respiration, sweating, and waste elimination, and needs vary depending on the body, activity, and environmental conditions.
In hot weather, it's best not to wait until you're very thirsty. A practical approach is to drink small amounts throughout the day, keep water nearby, take a bottle with you when you're out and about, add fluids to each meal, and pay close attention to how you feel.
How to understand that there is not enough fluid
The simplest everyday reference points are thirst, dry mouth, and urine color. If urine is very dark, scanty, or if you experience weakness, dizziness, headache, or extreme fatigue, this may indicate dehydration. Symptoms of dehydration include thirst, dark yellow urine with a strong odor, urinating less often than usual, dizziness, fatigue, and dry mouth, lips, and eyes.
But urine color is not a perfect test. It is affected by vitamins, medications, diseases, food, kidney function, and the amount of alcohol consumed in a short period of time. Therefore, it is better to evaluate not one indicator, but the overall picture: temperature, exercise, sweating, pulse, well-being, the presence of vomiting or diarrhea.
Symptoms that should not be limited to home remedies include: confusion, fainting, very fast heartbeat, difficulty breathing, seizures, high fever, no urine, severe weakness or worsening of condition despite drinking. The NHS notes that rapid breathing, rapid pulse or severe signs of dehydration may require urgent medical attention.
What is better to drink in the heat?
The basis should be ordinary drinking water: room temperature or cool, if that is more pleasant. Ice water is not necessary and does not “cure” overheating faster. If very cold water causes a sore throat, stomach discomfort, or a person begins to drink less, it is better to choose just cool water.
Good options for most people:
plain water;
water with lemon, mint, cucumber or berries without sugar;
unsweetened tea;
weak green or herbal tea;
soups, cold soups and other dishes with a high liquid content;
mineral water without excess sodium, if there are no medical restrictions;
oral rehydration solutions in cases where water and salts are lost.
If you have hypertension, heart failure, kidney disease, are taking diuretics, or are on a salt restriction, you should not switch to salty mineral waters or electrolyte supplements on your own. In such cases, it is best to discuss your drinking and salt regimen with your doctor.
When are electrolytes needed?
Electrolytes are not necessary for everyone, and not always. If you work in an office, go for a short walk, and eat normally, plain water and food are often enough. But there are situations when electrolytes are really appropriate.
For moderate activity in the heat lasting up to 2 hours, the organization recommends drinking about 1 cup of water every 15–20 minutes. If sweating continues for several hours, the organization recommends drinks with balanced electrolytes.
In the case of heat exhaustion, it is advisable to move the person to a cool place, cool the body, and give plenty of water; an isotonic sports drink or oral rehydration powder mixed with water can also be given to help replace salts lost through sweat.
Electrolytes may be needed if:
you work or exercise for several hours in the heat;
sweat is literally dripping, clothes are wet;
there are heat cramps;
had diarrhea or vomiting;
there is fever and heavy sweating;
you are outside for a long time without air conditioning;
weakness, headache, dizziness appeared after the heat.
This does not mean that you should drink sports drinks every day “for prevention.” Many of them contain a lot of sugar, flavorings, or colorings. For everyday heat, water, normal food, vegetables, fruits, soup, and a moderate amount of salt in the diet are often enough.
When is rehydration solution needed?
Oral rehydration solution is not just “salt water.” It is a mixture of pure water, salts, and glucose in the correct proportions that helps the body better restore fluids and electrolytes. Such solutions are especially important in cases of diarrhea, vomiting, and heat exhaustion.
The WHO explains that during diarrhea, water and electrolytes — sodium, chloride, potassium, and bicarbonate — are lost, and treatment should include an oral rehydration solution made from pure water, salt, and sugar.
For diarrhea and vomiting, it is also advisable to use oral rehydration powders that are mixed with water, especially if the person is at risk of dehydration.
It’s useful to have pharmacy rehydration sachets in your home medicine cabinet during the summer. They should be diluted exactly as directed: don’t make them more concentrated “to make them work better” and don’t dilute them in less water.
What is better not to drink in the heat?
In hot weather, it's best to limit drinks that are high in sugar, alcohol, or excess caffeine. They can make you feel worse, interfere with thirst control, add calories, or contribute to fluid loss in certain conditions.
In hot weather, consider limiting beverages high in sugar and sodium, caffeine, and alcohol.
Particularly undesirable:
alcohol in any form;
sweet carbonated drinks;
energy;
very sweet iced teas;
many coffees one after another;
strong cocktails;
drinks that make you want to drink even more.
Alcohol is dangerous in its own right in the heat: it can dull your sense of risk, increase your loss of control, disrupt your sleep, interact with medications and make it harder to regulate your temperature. The NHS's heat advice specifically advises drinking extra fluids, but avoiding alcohol, caffeine and hot drinks.
Coffee and tea: can or not
Coffee and tea don't have to be automatically banned for everyone. Moderate amounts of caffeine don't cause dehydration for most people. The Harvard TH Chan School of Public Health explains that more than 180 mg of caffeine per day — about two cups of brewed coffee — can temporarily increase urination in some people, but doesn't necessarily cause dehydration.
In practice, this means: one morning coffee is not a disaster. But in the heat, you should not make coffee your main source of fluid, drink it instead of water, add a lot of sugar or combine it with alcohol. If after coffee you feel more thirsty, have palpitations or anxiety, it is better to reduce the amount and add water.
Weak green, black, or herbal tea without sugar can be part of your daily fluid intake. But if it's very hot outside and you're sweating heavily, the priority should be water, a cool environment, rest, and electrolytes if needed.
Is it possible to drink too much water?
Yes, although this is rare for most people in everyday life. The risk increases when a person drinks a lot of water in a short period of time, especially during marathons, long workouts, or other strenuous activity, and does not replace electrolytes.
Hyponatremia is when the sodium level in the blood becomes too low; this can happen, for example, when a person loses sodium through sweat during endurance activities and drinks excessive amounts of water. Serious symptoms can include nausea, vomiting, confusion, seizures, or loss of consciousness.
This is not a reason to be afraid of water. This is a reason not to drink liters “by force” and not to perceive clear urine all day as a mandatory goal. Drink regularly, but wisely: according to thirst, conditions, sweating, food and well-being.
What to eat in the heat
Eating in the heat should help, not overwhelm. When it's very hot, many people find it harder to digest heavy, fatty foods, large portions, alcoholic feasts, and very salty snacks without enough fluids. It's better to keep your meals light, but not avoid them altogether.
Suitable:
vegetables with high water content: cucumbers, tomatoes, leafy greens, zucchini;
fruits and berries: watermelon, melon, peaches, apricots, berries, citrus fruits;
cold soups;
fermented milk products, if they suit you;
dishes with legumes and cereals in moderate portions;
fish, eggs, lean meat or other sources of protein;
a small amount of salty foods with heavy sweating, unless there are medical restrictions.
Food also provides fluids. The Mayo Clinic reminds us that daily fluid needs include water, other beverages, and food. So fruits, vegetables, soups, and dairy products can really help keep you hydrated, but they're no substitute for drinking water in hot weather.
Who needs to be especially careful?
Anyone can get sick from heat, but some groups are at higher risk. The CDC notes that heat illnesses can happen to anyone, but some people are more vulnerable.
Particular attention should be paid to:
small children;
older people;
pregnant;
people with heart disease, kidney disease, diabetes;
people taking diuretics or certain other medications;
workers on the street;
athletes;
obese people;
those who live without air conditioning or in poorly ventilated housing;
people who cannot take care of their drinking on their own.
The NHS also reminds people to check children, older people and people with long-term conditions such as diabetes or heart disease, as they are at higher risk of heat exhaustion or heatstroke.
Heat exhaustion and heat stroke: when water is no longer the main thing
If someone is feeling unwell from the heat, it is important not just to give them a bottle of water, but to cool them down quickly. The NHS advises that in the event of heat exhaustion, move the person to a cool place, remove excess clothing, cool the skin with water, a fan or cold packs wrapped in a cloth, and give them water or a rehydration drink.
Signs of heat exhaustion may include heavy sweating, weakness, headache, dizziness, nausea, muscle cramps, thirst, and a rapid heart rate. If the condition does not improve after cooling or if confusion, fainting, a very high fever, seizures, or lack of normal responsiveness occur, it may be heat stroke, an emergency.
The WHO's heat advice states: "If you have painful muscle cramps in the heat, you should immediately rest in a cool place and drink oral rehydration solutions with electrolytes. If heatstroke is suspected, aspirin or paracetamol should not be given."
Common mistakes in the heat
The first mistake is to wait until you “really want to drink.” In the heat, it’s better to drink in small portions beforehand, especially if you have to walk around the city, ride public transport, or work outside.
The second mistake is to drink only ice water in large sips. This can cause discomfort and does not solve the electrolyte problem with prolonged sweating.
The third mistake is to replace water with sweet soda, juice, or energy drinks. These drinks can be high in sugar and not restore the necessary balance.
The fourth mistake is drinking alcohol “because it’s a cold beer.” In the heat, alcohol worsens risk control and is not a way to hydrate.
The fifth mistake is drinking only water for hours during strenuous physical work or sports in the heat. In such conditions, electrolytes, food, or a rehydration solution may be needed.
The sixth mistake is to ignore symptoms. If a person is confused, faints, does not sweat in extreme heat, has seizures, or cannot drink, home remedies are no longer enough.
A practical plan for a hot day
Drink water and eat normally in the morning, don't leave the house on an empty stomach if you have a long drive or work ahead. Take a bottle of water with you. If you have to be outside for a few hours, add a snack: fruit, yogurt, sandwich, nuts, saltine crackers or another product that suits you.
Reduce your activity during the hottest hours. The CDC recommends staying in air-conditioned rooms, wearing light clothing, drinking throughout the day, and limiting beverages high in sugar, sodium, caffeine, and alcohol.
If you are working or exercising in the heat, drink regularly, take breaks in the shade, cool down, don't ignore cramps or wait until they get worse. If sweating continues for several hours, consider an electrolyte drink or rehydration solution as appropriate.
Conclusion
In the heat, water is the basic and most important drink, but it does not always cover all the body's needs. If it's a normal day, you are not sick and do not sweat for hours, it is enough to drink water regularly, eat light meals with vegetables and fruits, and avoid alcohol and excess sugary drinks.
If there is prolonged sweating, physical work, sports, diarrhea, vomiting, heat cramps, or signs of dehydration, a more careful approach is needed: coolness, rest, small portions of fluids, electrolytes, rehydration solution, and medical attention if necessary.
The best strategy is not to “drink water” but to maintain a balance: drink regularly, eat enough, do not lose salt without replacing it, monitor symptoms, and do not take risks during the heat.
FAQ
What is better to drink in the heat?
For most people, plain water is the best base drink. If you sweat a lot, work or exercise in the heat, you may need electrolytes or a rehydration solution. The CDC recommends using electrolyte-balanced drinks for prolonged sweating.
Is it enough to just drink lots of water?
Not always. In normal heat, water helps to stay hydrated. But with prolonged sweating, vomiting, diarrhea, or heat cramps, the body also loses salts, so electrolytes or an oral rehydration solution may be needed.
How much water should you drink per day?
Needs vary from person to person. The Mayo Clinic suggests a guideline for total fluid intake for healthy adults: about 3.7 liters per day for men and 2.7 liters for women, including fluids from food and other beverages. Needs may increase in hot weather, during activity, or when you are sick.
Can you drink coffee in the heat?
Yes, as long as it's in moderation and you can tolerate it. But coffee shouldn't replace water. Harvard explains that caffeine can temporarily increase urination in some people, but it doesn't necessarily cause dehydration.
Can you drink alcohol in the heat?
It is best to avoid alcohol. It can make you feel worse in hot weather, interfere with risk management and is not a way to hydrate. The NHS advises drinking more fluids in hot weather, but avoiding alcohol, caffeine and hot drinks.
When are electrolytes needed?
Electrolytes are appropriate for prolonged physical activity in the heat, heavy sweating for several hours, heat cramps, vomiting, or diarrhea. If you are simply sitting in a cool room and eating normally, special electrolyte drinks are usually not necessary.
Is mineral water useful in hot weather?
Mineral water can be beneficial if it helps you drink more and partially restores salt. However, people with hypertension, kidney disease, heart disease, or salt restriction should be cautious about high-sodium waters and consult a doctor.
What to eat in the heat?
It is better to choose lighter meals, vegetables, fruits, berries, cold soups, fermented milk products, normal sources of protein and moderate amounts of salt, if you sweat a lot and have no medical restrictions. Food also provides part of the daily fluid.
What are the symptoms of dehydration?
Thirst, dry mouth, dark urine, infrequent urination, fatigue, dizziness and headache can all be signs of dehydration. The NHS also notes that rapid breathing, a rapid pulse or worsening of your condition can be signs of serious dehydration and require urgent care.
When should you seek medical attention?
Seek immediate medical attention if you have confusion, fainting, seizures, a very high fever, inability to drink, no urine, rapid breathing, a rapid pulse, or if your condition does not improve after cooling and drinking. This could be a sign of severe dehydration or heatstroke.
