Are you drinking too much water? The myths and facts behind hydration

Few well being suggestions sound easier than “drink extra water.” It appears logical sufficient: greater than half of the human physique is made up of water, and we’re continually reminded how necessary hydration is.

However behind that acquainted recommendation are a number of questions which might be much less simple than they seem. How a lot water do we actually want? Can we belief thirst? What does urine shade really inform us? And will everybody actually purpose for 3 liters a day? Dr. Kay Alkara, a household doctor with Maccabi Healthcare Companies in northern Israel, explains what issues and which acquainted hydration guidelines deserve a re-assessment.

“Water isn’t simply one thing we drink so we gained’t really feel thirsty. It takes half in virtually each system within the physique,” Dr. Alkara mentioned.

Water helps keep blood quantity, helps regular cell and tissue operate, performs a task in digestion and permits the kidneys to take away waste. One in every of its most noticeable roles, particularly in summer time, is regulating physique temperature.

“When the physique heats up, it makes use of sweating and evaporation to launch warmth,” she defined. “However that efficient cooling mechanism comes at a worth. The extra we sweat, the extra fluid we lose, and subsequently the necessity to substitute it will increase.”

That’s the reason fluid wants rise throughout train, in scorching climate and in conditions the place the physique loses fluids quickly, resembling fever, vomiting and diarrhea.

Sweating could also be the obvious instance, however water additionally performs much less seen and equally important capabilities contained in the physique. “The kidneys filter the blood and take away waste by way of urine. Fluid stability is carefully tied to their potential to operate correctly,” Dr. Alkara mentioned. Enough fluid consumption additionally helps digestion and will help stop constipation.

There isn’t any single quantity of water that’s proper for everybody every single day. One of the regularly cited suggestions comes from the U.S. Nationwide Academies, which places complete day by day water consumption at about 3.7 liters for males and a pair of.7 liters for girls.

However there is a crucial distinction. “That determine contains all of the water the physique will get from meals and different drinks, not simply the plain water you drink from a bottle,” Dr. Alkara emphasised.

These figures apply to wholesome folks below average situations, she added, with fluid wants growing in scorching climate and through bodily exercise. So the often-cited “three liters a day” rule doesn’t imply everybody must drink three liters of plain water from morning to nighttime.

There’s additionally no easy scientific foundation for assuming that ingesting extra is at all times higher. A 2024 systematic assessment revealed in JAMA Community Open examined 18 randomized research that checked out what occurs when water consumption is modified. Some discovered potential advantages, together with results on weight reduction or fewer kidney stone episodes, whereas others discovered no clear benefit.

“The proof for well being advantages from growing water consumption stays restricted and inconsistent,” Dr. Alkara mentioned. For that cause, there isn’t a clear foundation for recommending that everybody merely drink considerably extra water.

Put extra merely: relating to water, extra isn’t essentially higher. The aim is to drink sufficient.

If there isn’t a magic variety of glasses or liters, how are you aware when to drink? For many wholesome folks, the physique already has a fairly efficient warning system: thirst.

“Feeling thirsty is a part of the physique’s pure regulation mechanism,” Dr. Alkara mentioned. Meaning each sip doesn’t must be scheduled prematurely, and most of the people don’t essentially want an app reminding them to drink all through the day.

There are exceptions, nevertheless. In scorching climate and through train, fluids could also be misplaced extra rapidly, and in some populations thirst itself is a much less dependable sign.

One other easy clue is urine shade. “Normally, pale yellow urine normally corresponds with higher hydration, whereas darker, extra concentrated urine could be a signal that the physique wants extra fluids,” Dr. Alkara defined.

However she cautioned towards treating urine shade as a medical take a look at. “It will probably additionally change due to meals, medicines and different situations,” she mentioned.

Dehydration happens when the physique loses extra fluid than it takes in. It will probably start after hours within the warmth, throughout train or throughout an sickness involving fever, vomiting or diarrhea. As fluid loss continues, signs can develop into extra severe.

“Indicators of dehydration can embody thirst, dry mouth, headache, fatigue, weak spot, dizziness and diminished urine output,” Dr. Alkara mentioned. “In additional vital instances, confusion, low blood strain and deterioration generally situation can happen.”

However not each headache or feeling of fatigue ought to instantly be blamed on dehydration. “These are widespread signs that may have many causes,” she mentioned. “But when they seem along with darkish urine, diminished urination, warmth publicity or vital sweating, fluid deficiency must also be thought-about.”

In Israel, these warnings tackle added significance in periods of maximum summer time warmth, significantly for folks spending time outdoor, working bodily or exercising. “Individuals who drank a certain quantity on a cool, air-conditioned day might not be capable of get by on the identical quantity throughout heavy warmth,” Dr. Alkara mentioned.

Older adults deserve explicit consideration. “For a wholesome particular person, thirst is a part of the physique’s pure regulation mechanism, however in older adults it isn’t advisable to depend on thirst alone,” she mentioned.

Older individuals are at larger threat of heat-related issues due to age-related modifications within the physique’s response to warmth, underlying sicknesses and sure medicines.

The difficulty might be much more difficult for individuals who require nursing care. “You can’t at all times assume {that a} dependent particular person will ask for water,” Dr. Alkara mentioned. “Generally there’s a diminished sensation of thirst, bodily issue reaching a drink or concern about needing to make use of the toilet.”

In such instances, members of the family and caregivers have a larger duty to make sure that fluids can be found and truly being consumed.

A assessment revealed in Might 2026 in BMJ Public Well being discovered that dehydration associated to low fluid consumption was widespread amongst hospitalized older adults, with an estimated prevalence of about 23%, Dr. Alkara famous. Researchers additionally mentioned earlier research had linked this kind of dehydration with larger mortality and poorer well being outcomes.

Younger kids additionally require particular consideration throughout scorching climate. “In contrast to an grownup who can acknowledge thirst and go fill a glass, younger kids rely on adults to verify they’ve sufficient entry to fluids,” she mentioned.

After all of the warnings about dehydration, it’s straightforward to overlook that there’s additionally a restrict within the different course. Sure, it’s attainable to drink an excessive amount of water, and in excessive instances it may be harmful.

“When somebody drinks an unlimited quantity of water over a brief interval, the kidneys might not be capable of eliminate the surplus rapidly sufficient,” Dr. Alkara defined. “The consequence could be a drop in blood sodium focus, a situation often called hyponatremia.”

That may have severe penalties. “When sodium ranges fall, water enters the cells and causes them to swell,” she mentioned. “In extreme instances, cerebral edema can develop, inflicting seizures and even develop into life-threatening.”

For a wholesome particular person going a couple of regular routine, nevertheless, that is uncommon. The chance rises primarily when very giant portions are consumed in a short while, together with throughout extended endurance train, when some athletes attempt to stop dehydration by ingesting far past their precise wants.

One excessive case resurfaced in Australia in 2026 throughout an investigation into the demise of 47-year-old Tammy Shipley, who died in 2022 after consuming extraordinary portions of water.

Proof offered within the case indicated that she drank at the least 67 glasses in about 12 hours. If every glass contained roughly 300 milliliters, that might quantity to about 20 liters over half a day. An post-mortem decided that she died from hyponatremia linked to compulsive overconsumption of water.

It was an distinctive case, and wholesome folks don’t have any cause to concern an odd bottle of water. But it surely illustrates an necessary precept: even with water, extra isn’t mechanically higher.

As soon as the query of how a lot to drink is settled, a number of different persistent beliefs stay. One of the widespread is the supposed significance of ingesting a glass of water instantly after waking.

“There isn’t any particular medical want for a wholesome particular person to drink a certain quantity of water instantly after waking up,” Dr. Alkara mentioned. For those who get up thirsty, by all means drink. However the concept a morning glass of water “flushes toxins” or triggers a particular detox course of is one other matter.

“The kidneys and liver perform the physique’s waste-removal processes repeatedly,” she mentioned. “Water helps their regular operate, however there isn’t a must current ingesting water within the morning as a medical remedy in itself.”

One other common declare is that ingesting one or two glasses earlier than a meal helps with weight reduction by making folks really feel fuller. Once more, the image is extra difficult. “Ingesting a glass of water earlier than a meal isn’t an alternative to a balanced weight loss plan,” Dr. Alkara mentioned.

A scientific assessment and meta-analysis of eight randomized trials involving folks with obese or weight problems discovered that merely growing water consumption didn’t considerably cut back physique fats. Changing sugary drinks with water, nevertheless, might assist by reducing sugar and calorie consumption.

And what in regards to the longstanding debate between faucet water and mineral water? “By way of hydration, the necessary factor is to drink water,” Dr. Alkara mentioned.

In Israel, ingesting water is monitored by the Well being Ministry, with tens of hundreds of microbiological and chemical exams carried out annually all through the availability chain. The general public also can assessment ingesting water high quality information by way of the ministry’s “My Water” on-line database system.

Mineral content material additionally varies from one supply to a different. “The mineral content material differs amongst totally different water sources, and magnesium concentrations in faucet water additionally range by location,” Dr. Alkara mentioned.

She added that the Well being Ministry notes there’s presently no World Well being Group advice establishing a minimal magnesium focus for ingesting water.

So which is healthier? For a wholesome particular person, there isn’t a absolute winner. “The selection between faucet water and mineral water is essentially a matter of style, comfort and private desire, so long as the water is secure to drink,” Dr. Alkara concluded.