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Water & Electrolytes
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In one pass What the body really manages is not how much water you drank but which compartment the water sits in and whether its concentration is stable. Not this — Hydrogen water is anti-oxidant + anti-inflammatory — H₂ solubility in water is tiny (~1.6 mg/L); a 500 mL bottle delivers ≤0.8 mg — orders of magnitude below animal dosing.
Educational content, not medical advice — consult a clinician.
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Chapter 1
Where water lives
What the body really manages is not how much water you drank but which compartment the water sits in and whether its concentration is stable.
The water in your body is held in several compartments: the fluid inside cells is the largest, the fluid between cells comes next, and plasma, the liquid part of blood, is the smallest. Yet when you sweat, it is exactly this smallest share that is drawn on first, because sweat glands can only take water from the blood. What holds plasma inside the vessels is the pull of albumin, a protein in the blood. Swollen legs (edema) are usually not a sign of drinking too much either; something has gone wrong with this balance elsewhere, and the answer is to find the cause, not to drink more or less on your own.
Extra water you drink is soon sent out by the kidneys as urine; the kidneys do the clearing, not the drinking itself.
One thing to know first: if, during or after a long endurance event or long hours of work in the heat, headache and nausea are joined by confusion, vomiting, or seizures, drinking too much may have diluted your blood sodium. Get emergency care right away, and stop drinking water.
The water in your body is held in several compartments: the fluid inside cells is the largest, the fluid between cells comes next, and plasma, the liquid part of blood, is the smallest. Yet when you sweat, it is exactly this smallest share that is drawn on first, because sweat glands can only take water from the blood. What holds plasma inside the vessels is the pull of albumin, a protein in the blood. Swollen legs (edema) are usually not a sign of drinking too much either; something has gone wrong with this balance elsewhere, and the answer is to find the cause, not to drink more or less on your own.
Extra water you drink is soon sent out by the kidneys as urine; the kidneys do the clearing, not the drinking itself.
One thing to know first: if, during or after a long endurance event or long hours of work in the heat, headache and nausea are joined by confusion, vomiting, or seizures, drinking too much may have diluted your blood sodium. Get emergency care right away, and stop drinking water.
Numbers · How much water, and where
Total body water (all the water in the body) as a rough share of body weight: about 60% in adult men (about 42 L in a 70 kg man); about 50–55% in adult women (fat tissue holds little water, and women usually carry a higher share of body fat); about 75% in infants, who dehydrate easily; and about 50% in older adults, where age and falling muscle mass, plus a blunted sense of thirst, put them at high risk of dehydration.Body water sits in three compartments. Intracellular fluid, inside cells, is 2/3 of total body water, about 28 L. Its main positive ion is potassium (about 150 mmol/L), along with plenty of protein, magnesium, and phosphate; nerves, muscles, and nearly every metabolic enzyme work here. Extracellular fluid, outside cells, is 1/3 of total body water, about 14 L, split in two: interstitial fluid, between cells (about 75% of extracellular fluid, 10.5 L), dominated by sodium (about 140 mmol/L) with almost no protein; and plasma (about 25% of extracellular fluid, 3.5 L), also dominated by sodium but carrying a large amount of albumin (about 40 g/L).
So plasma, at only about 3.5 L, is the smallest of the three compartments, yet it is the one the circulation actually runs on.
Mechanism · What holds water inside the vessels
The core physics of holding water inside the vessels is albumin. Albumin in plasma creates a force on the inner side of the vessel wall that pulls water back in, called oncotic pressure (about 25 mmHg). At the arterial end of a capillary, hydrostatic pressure (about 32 mmHg) pushes water out into the tissue; by the venous end, hydrostatic pressure has fallen to about 12 mmHg, oncotic pressure wins, and water is drawn back into the vessel. This is the classic textbook Starling balance: 95% of the water that leaks out returns to the vessels, and 5% enters the lymphatic circulation.Newer research has revised that picture: in most tissues at steady state, far less water is actually drawn back at the venous end, and more of it is returned to the blood by the lymphatic vessels. Both versions agree on one thing: albumin in the blood is the main force keeping water inside the vessels, and when it falls, water tends to move into the tissues.
Clinical · Swelling is not from drinking too much
Edema (extra water collected in the tissues) does not mean you drank too much. Sorted by the forces in the Starling balance, the common causes fall into three groups:Pressure in the vessels is too high and pushes water out: heart failure, poorly working leg veins, kidneys holding on to salt and water, and some drugs (such as the calcium-channel-blocker class of blood-pressure drugs).Albumin is too low to hold water in: malnutrition, cirrhosis, nephrotic syndrome, severe burns.Capillaries become leaky: sepsis, severe inflammation, allergic reactions.
So the question with swollen legs is not drink more or drink less but which kind of cause it is, and treating that underlying disease. With low albumin, check whether protein intake is adequate and whether the liver and kidneys are working; with heart failure, doctors usually restrict salt and sometimes fluid. Pouring in water on your own will not help, and neither will forcing yourself to drink less. Leg swelling that does not go away over a long period calls for checks of the heart, liver, and kidneys.
Chapter 2
Why water runs out first
Water ranks first among nutrients not because it is nourishing but because other shortages can be ridden out for a while, whereas a water shortage immediately drains the share the circulation actually runs on: plasma. The heart has to be stretched open by returning blood before it can squeeze any out. When less blood returns, the amount pushed out with each beat (stroke volume) falls, and heart rate climbs to make up for it, but that fix has a ceiling.
When it can no longer hold, the body cuts secondary users in order of priority: skin, gut, and kidneys are clamped first, and brain and heart are protected longest. Pouring in plain water, though, turns a different knob: it replaces water, not salt, and dilutes blood sodium. Volume and concentration are two independent knobs, and safety lies in not turning either one all the way.
When it can no longer hold, the body cuts secondary users in order of priority: skin, gut, and kidneys are clamped first, and brain and heart are protected longest. Pouring in plain water, though, turns a different knob: it replaces water, not salt, and dilutes blood sodium. Volume and concentration are two independent knobs, and safety lies in not turning either one all the way.
Mechanism · How plasma volume fails first
Water ranks first among nutrients not because it is the most nourishing; it carries no nutrition at all. It ranks first because every other shortage lets you cope for a while, and only a water shortage reaches straight into the circulation itself.Your body water sits in three compartments: intracellular fluid is the largest, interstitial fluid next, and plasma is the smallest. Yet that smallest share is the one the circulation actually runs on.
It is also the only one that can be drained by the hour. When you sweat, have diarrhea, or vomit, the water comes out of plasma first, because sweat glands can only draw water from the blood. Water inside cells does shift across along the osmotic gradient to refill it, but it moves in more slowly than it is lost. Hard work on a hot day can cost one to two liters of sweat an hour (Sawka 2007), while plasma totals only a few liters. That ratio is where everything else starts.
The heart is filled first, then squeezes
The heart is not a pump you set to a flow rate. It has to be stretched open by blood before it can push any out.
During diastole, the relaxed phase of each beat, returning blood stretches the ventricle. The more it stretches, the longer the heart-muscle fibers are pulled, and the harder the next contraction squeezes. That relationship is the Frank-Starling mechanism (Delicce 2023).
Run it backward and you have the core of this chapter: less blood returning means the ventricle cannot stretch open, so the same contraction ejects less blood. The amount ejected per beat is stroke volume.
Heart rate can climb to compensate; the pounding you feel running in the heat is exactly this (González-Alonso 2008). But it is compensation with a ceiling: the faster the beat, the shorter diastole gets, the less time the ventricle has to fill, and the lower stroke volume falls.
The body starts making trade-offs
Blood delivered per minute equals stroke volume times heart rate. When that product can no longer hold, the body does not shave a little off every organ. It cuts by priority (Taghavi 2025).
Skin is clamped first: blood is pulled back from the surface toward the core, and your ability to shed heat drops on the spot. So running short of water in the heat brings heatstroke on sooner: cooling and keeping the circulation going are competing for the same blood.The gut is clamped next: falling blood flow to the abdominal organs brings nausea and cramping (van Wijck 2012). Feeling sick late in a long run is a common result of this, not necessarily something you ate.The kidneys are ordered to claw water back: urine becomes scarcer and more concentrated.Brain and heart are protected longest: the signal to constrict vessels gets little traction on theirs, so blood is left to them first.
So the first things you notice, sweating suddenly dropping off, scarce urine, feeling a bit sick, are not scattered symptoms of dehydration. They are a direct readout of the body shutting down secondary users in order. It works up the list from the bottom, and the brain is last.
This is why water ranks ahead of every nutrient. A vitamin shortage is a production line winding down: stores drain first, then output slips bit by bit. A water shortage gives you no such buffer, because the share being drained is the very share the circulation depends on to stay full.
Mechanism · Two knobs: volume and concentration
Two knobs: do not turn only oneOne thing has to be added right away, or this chapter tips into its own opposite.
Volume mattering does not mean pouring in water is safe. Plain water replaces water, not salt, and the blood gets diluted; that road ends in hyponatremia, low blood sodium, which also kills (the chapter on how drinking too much water can kill covers it in detail).
Volume and concentration are two independent knobs:
Losing water turns the volume knob: there is not enough blood in the circuitPouring in plain water turns the concentration knob: blood is diluted and sodium falls
Safety means not turning either knob all the way, not maxing out one of them. That is why this story says drink to thirst from beginning to end, rather than drink more.
Thirst is an early alarm, not a late one
The body has two sets of sensors; here is the division of labor (how they work is explained in the chapter on what makes you thirsty). The set watching concentration is very sensitive and alarms at a small shift: that is thirst. The set watching volume is far blunter and only moves once volume has dropped a fair way (IOM 2005).
The order is the key: thirst comes first; a pounding heart and graying out when you stand come later. By the time the volume sensors move, you are already a notch behind.
So for healthy adults in daily life, drinking to thirst is enough, since thirst already builds in lead time; just do not mute it as noise. For them, thirst is not a late signal, and there is no need to drink ahead of it.
In practice · How to tell if you are low on water
Why weighing yourself around exercise beats reading urine colorUrine color shows how far the kidneys concentrated the urine, and the kidneys follow a hormonal order, an order that answers to osmolality, stress, and nausea all at once. Urine color is a processed signal.
Body weight is not. Across the few hours of one workout you cannot gain or lose tissue, so a change in weight is essentially a change in water: losing one kilogram is about one liter gone (Sawka 2007). It reads volume directly, with no hormonal processing in between.
Weight down slightly after exercise: normal, that is sweatWeight down markedly: volume is falling; replace it, and include saltWeight up instead of down: you drank too much, and this is the red light for exercise-associated hyponatremia
One scale, readable from both ends.
Graying out when you stand is the same chain
The gray-out older people get when they stand up is tied to plasma volume.
The moment you stand, blood sinks into your legs and abdomen, less returns to the heart, ventricular filling drops a notch, and stroke volume follows. Younger people use pressure sensors in the vessel walls (baroreceptors) to tighten their vessels and raise heart rate at once, recovering within a second or two.
In older people that reflex is already slower, and their veins have less tone (Low 2015). If volume is also running a little low, in summer, on diuretics, or after a day of barely drinking, blood flow to the brain dips briefly and everything goes gray. Falls often begin in that one second.
Staying upright without fainting rests on three things at once: enough plasma volume, sensitive baroreceptors, and veins with tone (Low 2015). In older people the last two are fading, which is exactly why the first cannot be given away as well.
Something you already know the conclusion of
The story Exercising in the Heat says heat acclimation expands plasma volume (Périard 2015 lists it among the core cardiovascular adaptations to heat and does not rank them). That story gives the conclusion without the reason. Now you have it: expanded plasma is a margin added to the circulation that can afford to be drained. The ventricle keeps filling, stroke volume holds, and skin and muscle do not have to start competing for blood so early.
Red flag · When to get medical help
When this is past what drinking can fixThis scene is about the physiological chain, not first aid. Some situations have already moved beyond what fluids address, and need medical care immediately:
Confusion setting in, answers that don't track, unable to standSkin cold and mottled, slow to refill when pressedAlmost no urineA racing heart while the person gets steadily weaker
When these appear together, don't try to catch it back up at home by pouring in more water. This site is education and does not replace a doctor.
Chapter 3
What makes you thirsty
Thirst is not an alarm that total water is low but an alarm that plasma has become saltier. Cells in the hypothalamus that sense concentration are extremely sensitive: when it rises even slightly, they make you thirsty and at the same time release antidiuretic hormone (AVP, also called arginine vasopressin). It orders the collecting ducts of the kidneys to insert water channels and pull water that was headed for the urine back into the blood; without it, the channels withdraw and you pass large amounts of dilute urine.
The sensors that watch blood volume are much blunter and only move after a sizable drop. So healthy adults can drink to thirst, which already builds in lead time; in older and sick people thirst blunts, and they need fluid offered on a schedule. The slogan eight glasses a day has no evidence behind it.
The sensors that watch blood volume are much blunter and only move after a sizable drop. So healthy adults can drink to thirst, which already builds in lead time; in older and sick people thirst blunts, and they need fluid offered on a schedule. The slogan eight glasses a day has no evidence behind it.
Mechanism · Thirst and the AVP loop
Thirst is not an alarm that water is running low but an alarm that plasma osmolality is rising. You feel thirsty because the fluid outside your cells has become saltier (its sodium concentration has risen), not because total water has dropped. The two often happen together, but the mechanisms differ.The hypothalamus has two sets of sensors.
The first is the osmoreceptors, in a few small regions at the edge of the hypothalamus where the blood-brain barrier is loose (the organum vasculosum of the lamina terminalis and the subfornical organ). They watch plasma osmolality (normally about 285–295 mOsm/kg) and can trigger on a 1–2% change, which makes them very sensitive. Their output is thirst, which sends you looking for water, together with the release of antidiuretic hormone.
The second is the baroreceptors, in the carotid sinus, the aortic arch, and the atria, which watch blood pressure and blood volume. They are less sensitive and need a drop of about 10% in blood volume to trigger; once triggered, in an emergency, they release antidiuretic hormone and switch on the renin-angiotensin-aldosterone system (), the body's system for holding on to salt and water.
Antidiuretic hormone (ADH), also called arginine vasopressin (AVP), is simply the body's water-saving switch. It is made in the supraoptic and paraventricular nuclei of the hypothalamus, carried along nerve fibers to the posterior pituitary below the brain for storage, and released into the blood when needed. In the kidneys it binds the V2 receptor on collecting-duct cells, the signaling molecule cAMP rises inside the cell, and water channels stored in small vesicles inside the cell (AQP2, aquaporin 2) are inserted into the membrane facing the urine. Water crosses from the tubule through AQP2 into the cell, leaves by other water channels on the far side (AQP3 and AQP4), and returns to the blood, so urine becomes concentrated and the body keeps its water. Without the hormone, AQP2 stays inside the cell, the collecting duct stops letting water through, and you pass large amounts of dilute urine: this is exactly the mechanism of diabetes insipidus.
Why is thirst especially unreliable in older and sick people? With age, the osmoreceptors blunt and the hormone response weakens, so for the same degree of dehydration, thirst comes later and more weakly. After Alzheimer's disease, Parkinson's disease, or a stroke, the thirst signal may not get through. So the people at high risk of dehydration are older adults and people with chronic illness, not healthy adults. Healthy adults can drink to thirst, because this loop works; older and sick people need someone to offer fluid on a schedule.
Myth · Where eight glasses a day came from
Drink 8 glasses of water a day (8 × 8 ounces, about 1.9 L of plain water) is one of the most widely repeated health slogans, and no peer-reviewed evidence stands behind it.Valtin 2002 (published in the American Journal of Physiology by a Dartmouth kidney specialist) traced the literature and found no trial or consistent evidence supporting the 8 × 8 figure. The most likely source is a 1945 recommendation from the US National Research Council (NRC): about 1 mL of water for every 1 kcal of food eaten by an adult, about 2.5 L in all; the original text went straight on to say most of this quantity is already contained in food. As the advice was passed along, the second half was lost, leaving drink 2.5 L of water a day. Valtin also found no evidence that healthy people drinking beyond what thirst asks for improves kidney function, skin, weight loss, or so-called detox.
The adequate intake () for water comes from the 2005 Institute of Medicine (IOM) report on dietary reference intakes; the 2019 NASEM report updated only sodium and potassium and did not revisit water. The AI is 3.7 L for men and 2.7 L for women of total fluid: plain water, tea, coffee, soup, and milk, plus the water in food (fruit and vegetables are 80–90% water). About 80% of it comes from drinks (about 2.2 L for women and 3.0 L for men) and about 20% from food (roughly 500–700 mL); plain water is only part of the drinks, and there is no need to drink 2–3 L of it on its own.
Why is the extra benefit of drinking more close to zero for healthy adults? The kidneys can make urine very dilute or concentrate it to about 1200 mOsm/kg: drink more and urine dilutes, drink less and it concentrates, and the antidiuretic-hormone loop runs almost fully on its own. Thirst, urine color, and how often you urinate are far more accurate feedback than counting glasses.
Situations that really call for deliberate drinking are few:
Heavy physical work in the heat for 4 hours or more (construction, farm work at harvest, distance running): replace fluid, and include sodium (see the chapter on why sweat is not pure water)Fever, diarrhea, or vomiting: use oral rehydration solution (ORS, the World Health Organization formula), not plain waterOlder adults and people with dementia: offer fluid on a scheduleA history of kidney stones: drinking enough to pass about 2.5 L of urine a day is an evidence-based way to lower recurrencePeople on certain drugs (lithium, inhibitors): dehydration risk is higher, so watch for it
Only a few practical signs are worth tracking:
Pale straw-colored urine is good; clear urine means you drank more than needed; dark yellow or amber means you drank too littleHow often you urinate varies with the person and with how much you drink; a sudden, clear drop is worth noticingDark first-morning urine is not a sign of dehydration; it is the normal result of antidiuretic hormone working overnight
Chapter 4
Sweat is not pure water
Sweat is not pure water. Sweat glands first secrete a fluid close to plasma in composition, and as it flows along the sweat duct some of the sodium is taken back, so the sweat that reaches the skin still carries sodium, just less than blood does. Exercise intensity and weather can spread sweat rates very widely, which is why rehydration cannot follow one rule.
Sweating out toxins does not hold up: waste is cleared mainly by the liver and kidneys, and what sweat carries off is negligible by comparison. Sweating to lose weight is only temporary dehydration, and the weight returns as soon as you drink.
Sports drinks on the market were designed for long, hot, heavy sweating; everyday office drinking, ordinary gym sessions, and children drinking them as a treat are all the wrong setting, and what goes down is mostly a bottle of sugary drink. For severe diarrhea or vomiting, the right choice is oral rehydration solution (ORS), which uses glucose and sodium absorbed together to carry water into the gut wall.
Sweating out toxins does not hold up: waste is cleared mainly by the liver and kidneys, and what sweat carries off is negligible by comparison. Sweating to lose weight is only temporary dehydration, and the weight returns as soon as you drink.
Sports drinks on the market were designed for long, hot, heavy sweating; everyday office drinking, ordinary gym sessions, and children drinking them as a treat are all the wrong setting, and what goes down is mostly a bottle of sugary drink. For severe diarrhea or vomiting, the right choice is oral rehydration solution (ORS), which uses glucose and sodium absorbed together to carry water into the gut wall.
Numbers · What sweat contains, how fast it flows
What sweat contains: about 99% water; among the dissolved substances, sodium is the largest, with chloride following it; potassium is present only in small amounts; magnesium, calcium, and other trace elements are traces and do not matter; ammonia, lactate, and urea are traces too. Sweat sodium varies widely between people: those who are well trained and adapted to heat have lower sodium in their sweat, while beginners and people not yet adapted to heat have more. How much sodium one bout of sweating costs, and when to replace it, is given in numbers in the story Potassium & Sodium.Sweat rate spans a huge range from sitting still to the extreme: about 0.1 L/h sitting at room temperature; about 0.5 L/h for moderate exercise in cool weather; 1–2 L/h for hard exercise in the heat (a marathon, a triathlon, a building site in hot weather); and top endurance athletes in extreme heat can briefly reach 3 L/h.
The 2007 fluid-replacement position stand of the American College of Sports Medicine (ACSM; Sawka 2007) stresses that both sweat rate and the electrolytes in sweat vary widely between people, so fluid replacement should be planned for the individual; the simplest way to estimate your own sweat rate is to weigh yourself before and after exercise.
Myth · Detox, sports drinks and coconut water
Sweating out toxins: the body clears waste mainly through the liver and kidneys. A family of liver enzymes (the CYP enzymes) converts fat-soluble substances into water-soluble ones, which the kidneys then excrete. Traces of heavy metals and organic pollutants can indeed be measured in sweat, but next to what the kidneys excrete, they are negligible. Sweating to lose weight is temporary dehydration, and the weight returns as soon as you drink.The real problem with sports drinks is the wrong setting. They are designed for endurance exercise of 60 minutes or more, in heat, with sustained heavy sweating: the sugar fuels muscle, and the sodium helps hold blood volume. Yet the biggest markets are exactly the mismatched ones. Drinking them daily at the office, the sugar has no use and the sodium is not needed, so it amounts to a sugary drink, and heavy long-term intake of sugary drinks is linked with insulin resistance and a higher risk of type 2 diabetes (an observed association). An ordinary 30–60 minute gym session usually costs less than 0.5 L of sweat, and plain water is enough. Children drinking them as a treat rarely have any exercise to match; they are only learning a habit of sweet drinks. Sugar-free sports drinks replace sugar with sweeteners, which is better than the sugared version, but outside endurance settings they are still an intervention added to a body that has no problem. As for sodium, most sports drinks contain less of it than sweat does.
Coconut water is often marketed as a natural sports drink, but its composition is wrong for the job. By US Department of Agriculture (USDA) food-composition data, a cup (about 240 mL) of fresh coconut water holds about 600 mg of potassium, about 250 mg of sodium, and about 6 g of sugar; bottled unsweetened versions have even less sodium, about 60 mg. Sweat mainly costs sodium and very little potassium; coconut water is high in potassium and low in sodium, so its sodium-to-potassium balance runs the opposite way to sweat. Used as the main drink after heavy sweating, it brings back little sodium and, like large amounts of plain water, may keep diluting blood sodium. It is fine as an everyday drink, not as rehydration after heavy sweating.
Mechanism · Why oral rehydration salts work
Oral rehydration solution (ORS) is a different matter. The World Health Organization's standard formula (the low-osmolarity version revised in 2006) contains, per liter, 75 mmol of sodium, 65 mmol of chloride, 75 mmol of glucose, 20 mmol of potassium, and 10 mmol of citrate. It works through the glucose-sodium cotransporter (SGLT1) in the lining of the small intestine: every glucose molecule carried in brings sodium in with it, and water follows the sodium and glucose into the gut wall. During diarrhea, even while the gut is losing water, this pathway mostly keeps working, which plain water cannot use. It is widely regarded as one of the most important advances in medical history and has saved the lives of very many children with diarrhea.Without a ready-made packet, a common home recipe is 1 L of clean water with 6 level teaspoons of sugar and 0.5 level teaspoon of salt (not precise, but useful). Commercial sports drinks cannot replace it: too much sugar, not enough sodium. If diarrhea or vomiting is so severe that fluids will not stay down, or urine becomes scarce or the person becomes listless, go to a hospital.
Chapter 5
Drinking too much water can kill
In endurance events, drinking too much plain water is more dangerous than dehydration. Drink more than you sweat and the body's water rises on balance; the stress of exercise and nausea keep antidiuretic hormone (AVP) from falling even after the blood is diluted, the kidneys cannot clear the extra water, and blood sodium is diluted. This is exercise-associated hyponatremia. Once blood sodium falls, water follows osmosis into brain cells and the brain swells, which is cerebral edema. Weighing more after the race than before is the red light on this road.
Early headache and nausea look almost the same as dehydration, and drinking more at that point speeds the decline. If, during or after an endurance event or long hours of work in the heat, headache and nausea are joined by confusion, vomiting, or seizures, get emergency care right away and stop drinking water first.
Early headache and nausea look almost the same as dehydration, and drinking more at that point speeds the decline. If, during or after an endurance event or long hours of work in the heat, headache and nausea are joined by confusion, vomiting, or seizures, get emergency care right away and stop drinking water first.
Mechanism · How extra water becomes cerebral edema
Exercise-associated hyponatremia (EAH) means blood sodium falling during or after exercise. In mass-participation endurance events it is a serious complication that is often mistaken for dehydration.Almond 2005, a Boston Marathon study in the NEJM, is the classic dataset. At the 2002 race, 766 runners enrolled in the study and 488 gave a usable blood sample at the finish. Of them, 13% had hyponatremia (blood sodium ≤ 135 mmol/L) and 0.6% had critical hyponatremia (≤ 120 mmol/L). In the multivariate analysis, three things were independently associated with low sodium: gaining weight during the race ( 4.2), a finishing time over 4 hours (odds ratio 7.4 compared with under 3.5 hours), and a body mass index () that was either too high or too low. In the single-factor analyses, drinking more than 3 L, drinking at every mile, female sex, and low BMI were also linked with low sodium, but after adjustment, female sex was no longer independently associated; whether runners drank sports drinks or water, and whether they used nonsteroidal anti-inflammatory drugs, showed no association. This is a cohort study, so it gives associations; but weighing more instead of less is in itself evidence that more went in than came out.
Behind these numbers are real deaths: Almond's paper opens by noting that hyponatremia has become an important cause of race-related death and life-threatening illness among marathon runners. Those who died include healthy young runners, and cases have been reported in triathlons, 100-mile ultramarathons, and military training. What they often share is the belief that drinking lots prevents dehydration, and so deliberate overdrinking.
The mechanism breaks into 4 steps:
1. More plain water goes in than sweat takes out, so the body's water rises on balance.
2. Antidiuretic hormone stays abnormally high. Normally, once the blood is diluted, it should be suppressed so the kidneys pass dilute urine; but the stress of exercise, nausea, vomiting, and similar signals keep it raised even when the blood is already dilute, and the kidneys cannot clear the extra water.
3. Blood sodium falls: from 140 to 130 and then 120 mmol/L, and plasma osmolality falls with it.
4. Brain cells swell: plasma is now more dilute than the brain cells, water follows the osmotic gradient into them, and cerebral edema forms.
Then the symptoms escalate step by step: first headache, nausea, and vomiting, then confusion and seizures, and in severe cases coma and breathing that stops; it can kill.
The single most important clinical point: early EAH headache and nausea look almost the same as dehydration or heatstroke. These symptoms used to be taken for dehydration, and runners or coaches kept pouring in water, which sped the decline. For someone with headache and nausea during an endurance event, the first step is not more water but checking weight and blood sodium: weighing more than before the race is a strong warning of EAH; even a little weight loss does not rule EAH out, so blood sodium still needs checking as soon as possible.
The bottom line of prevention: drink when thirsty, not on a schedule; extra sodium cannot offset overdrinking. Do not deliberately store up water by drinking extra before the race; if you weigh more after the race than before, stop drinking. Those at higher risk are slower runners who spend longer on the course, and amateur runners doing their first marathon; for smaller people, the same volume of drinking makes up a larger share of their body water. And this is not only about marathons: it applies to any heavy physical work in the heat lasting 4 hours or more (building sites, farm work at harvest, long hikes).
Evidence · Who is at higher risk
EAH does not strike at random; it clusters in certain situations. But which factors are independent depends on the adjusted results.Slower runners who spend longer on the course are at highest risk. In Almond 2005, a finishing time over 4 hours was the independent risk factor with the largest : slower runners are out on the course longer, have longer to drink, and take in more in total, while faster runners simply have no time to drink too much. So elite runners rarely get EAH, and ordinary finishers in the middle and back of the field are at highest risk.
Gaining weight during the race is another independent factor, and it directly shows that more went in than came out.
Smaller people with a low : they carry less total body water, so the same net gain in water dilutes their blood sodium more, leaving a smaller buffer. Almond found that a BMI that was either too high or too low was linked with low sodium.
Women: in Almond's single-factor analysis their risk was higher, but after adjusting for body size, finishing time, and similar factors, the link no longer stood on its own. In other words, EAH may be more common in women mainly because they are smaller on average and take longer to finish.
People taking nonsteroidal anti-inflammatory drugs (painkillers in the ibuprofen and naproxen class): by mechanism, these drugs reduce blood flow to the kidneys and slow water excretion, so taking them while drinking heavily should in theory make water pile up; but Almond's data showed no link between the drugs and low sodium. So for now this is a precaution, not a proven risk factor.
People running their first marathon who are not adapted to heat: their sweat usually carries more sodium than a trained athlete's, so they lose more; and they are often the most convinced that drinking lots prevents heatstroke, so fear of dehydration drives them to overdrink.
A quick check before an endurance event or heavy work in the heat:
Under 4 hours: drink to thirstOver 4 hours with heavy sweating: you can add some sodium to your drinks (sports drinks or salt tablets), but extra sodium cannot offset overdrinkingNot thirsty: no need to drinkHeadache or nausea: stop drinking first; do not add more waterLosing 1–2% of body weight is acceptable; gaining weight is a red lightAround the race, as a precaution, go easy on ibuprofen-type painkillers
Chapter 6
Which water marketing claims fail
Water and electrolytes are a hot spot for health marketing, and the most common claims can be taken apart with basic chemistry and physiology.
Alkaline water fights acid and cancer does not hold up: stomach acid is itself a strong acid and neutralizes alkaline water within seconds, and blood acidity is not something diet gets to set; that is the job of the lungs and kidneys.
A daily packet of electrolyte powder is unnecessary for most people who sit at a desk all day, and can even backfire: everyday food already supplies too much sodium. The people who really need extra electrolytes are those facing long exercise in the heat, severe diarrhea, or burns.
Drinking more water cures migraine is overstated: dehydration can trigger headache, but for most migraine it is one minor trigger among many.
Coconut water is a natural sports drink does not hold either: its sodium-to-potassium balance runs the opposite way to sweat.
Alkaline water fights acid and cancer does not hold up: stomach acid is itself a strong acid and neutralizes alkaline water within seconds, and blood acidity is not something diet gets to set; that is the job of the lungs and kidneys.
A daily packet of electrolyte powder is unnecessary for most people who sit at a desk all day, and can even backfire: everyday food already supplies too much sodium. The people who really need extra electrolytes are those facing long exercise in the heat, severe diarrhea, or burns.
Drinking more water cures migraine is overstated: dehydration can trigger headache, but for most migraine it is one minor trigger among many.
Coconut water is a natural sports drink does not hold either: its sodium-to-potassium balance runs the opposite way to sweat.
Myth · Alkaline water, electrolyte powder, headaches
The first marketing claim is that alkaline water counters acid, fights cancer, and lowers blood pressure, blood sugar, and blood lipids. Stomach acid sits around pH 1.5–2.0, and alkaline water at pH 8–10 is neutralized within seconds of reaching the stomach; even if some alkali were absorbed, the kidneys would excrete the extra bicarbonate. Blood pH is held tightly within the narrow range of 7.35–7.45 by the lungs and kidneys, and food and drink cannot change it. The idea that an alkaline diet fights cancer fails even more clearly: the area around a tumor is already acidic, a result of the cancer cells' own metabolism (the Warburg effect), and changing the acidity of your diet does not change that. So alkaline water is just ordinary water at a higher price.The second is taking electrolyte powder or effervescent tablets every day. Office workers sweat very little on a normal day; most people already eat more salt than the limit, while potassium often falls short. Adding sodium powder only makes the excess worse and does blood pressure no good. Adding potassium powder, for someone with chronic kidney disease or taking blood-pressure drugs such as ACE inhibitors or that make the body retain potassium, can lead to dangerously high blood potassium and, in severe cases, cardiac arrest. Anyone in these situations should ask a doctor before taking potassium or using a potassium-based salt substitute. The situations that really call for electrolyte replacement are long exercise in the heat, severe diarrhea, burns, and heart failure treated with diuretics, and even then under professional guidance. The great majority of healthy adults have no need for electrolyte drink mixes.
The third is dehydration causes headaches, so drinking more water treats migraine. The first half is partly true: marked dehydration can trigger headache; but the evidence that mild everyday dehydration causes headache is weak. The paper often described as a Cochrane review is not one: Price 2015 is a critical appraisal of a single small trial (Spigt 2012, n=102). That trial's result was split: drinking more water improved people's own rating of migraine-related quality of life but did not reduce the number of headache days. Migraine is a neurovascular disease whose key signaling molecule is CGRP (see migraine); drinking habits may be one trigger, but only one factor among many. Drinking some water when a headache comes on does no harm, but do not expect miracles.
Myth · Sauna detox, cramps and mineral water
The fifth claim is that saunas and heavy sweating detoxify you. The toxins in sweat are negligible next to what the kidneys excrete. Researchers attribute the link between sauna and health to the load that repeated heat exposure puts on the cardiovascular system, somewhat like a form of training. Laukkanen 2015 followed 2,315 Finnish men aged 42–60 for a median of about 20 years: among men who took a sauna 4–7 times a week, 12.0% died of cardiovascular disease during follow-up, against 22.3% of those who went once a week, and the link held after adjustment for other risk factors. This is a cohort study, so it gives an association: men who take frequent saunas may already be healthier and have more leisure time. Either way, it is not about toxins leaving through sweat. Some detox circles recommend drinking large amounts of plain water after a sauna; losing sodium while gulping plain water points in the direction of the low-blood-sodium mechanism and is actually dangerous.The sixth claim is that cramps mean a lack of water, salt, or magnesium, and electrolyte drinks prevent them. The systematic review by Schwellnus 2009 concluded that the main cause of cramps during exercise is disturbed nerve control of muscle after muscle fatigue, not dehydration or electrolyte loss. Well-trained, fully hydrated athletes still cramp, and people running long distances for the first time tend to cramp late in the race. When a cramp strikes, stretching that muscle is what relieves it, not pouring in electrolytes. Electrolyte-related cramps do exist, but they are a minority, appearing only with long duration, heat, and heavy loss of several electrolytes. Night-time leg cramps are a different thing from exercise cramps; they are linked to age, circulation, and nerve damage, and the randomized-trial evidence for magnesium is weak. Quinine was once used for night cramps, but the US FDA has warned of its risks of heart-rhythm problems and low platelets, so do not use it on your own.
The seventh claim is that mineral water supplies minerals. Mineral content varies hugely between waters (calcium 0–500 mg/L, magnesium 0–100 mg/L). A high-calcium water (250 mg/L or more) is meaningful for people who eat little calcium, since drinking 1 L a day provides 250 mg or more; a high-magnesium water is meaningful for people short of magnesium. But between ordinary mineral water and tap water, the mineral difference is small while the price is much higher. Read the calcium, magnesium, and sodium figures on the label, not words like natural glacier.
laukkanen-2015-jama-sauna
Chapter 7
How much to drink, for you
How many glasses a day is the wrong question. The body manages two knobs, concentration and volume. A healthy adult's thirst loop is enough; thirst blunts in older adults, so fluid has to be offered; heart failure and some kidney diseases may instead call for limits on fluid and potassium, the complete opposite direction. Urine color is a processed signal, but pale straw is still the handiest everyday check; weighing yourself before and after exercise is more direct.
Only long, heavy sweating in the heat calls for sodium with the water; with headache and nausea, stop drinking rather than pour more in. Eating less sodium, more potassium, and avoiding sugary drinks do more for health than drinking extra water.
Only long, heavy sweating in the heat calls for sodium with the water; with headache and nausea, stop drinking rather than pour more in. Eating less sodium, more potassium, and avoiding sugary drinks do more for health than drinking extra water.
In practice · By person, not by cups
Forget the one-size-fits-all X glasses a day; decide by which group you are in.Healthy adults (18–60, no chronic disease, moderately active)
Drink to thirst: the antidiuretic-hormone loop works well enoughThe US adequate intake is 3.7 L a day for men and 2.7 L for women of total fluid, counting soup, tea, coffee, and the water in foodPale straw-colored urine means you are drinking about rightSodium: most people eat far more than the limit. WHO recommends that healthy adults keep sodium under 2 g a day, about 5 g of saltPotassium: many people eat too little. WHO 2012 suggests adults get at least about 3.5 g a day from food (a conditional recommendation), from vegetables, fruit, and beans, not supplements
Older adults (over 60, with blunted thirst)
Offer fluid on a schedule; do not rely on thirstSpread drinking across the three meals and a few times in betweenWatch urine volume and colorOn diuretics: take potassium only on a doctor's advice, never on your ownWater-rich foods such as porridge, soup, vegetables, and fruit are a gentle way to take in fluid
People with chronic disease
Heart failure: doctors usually limit fluid (1.5–2 L a day) and salt, so do not drink more on your ownChronic kidney disease (): potassium often needs limiting (be careful with bananas, potatoes, and coconut water), and sodium follows the doctor's adviceHypertension: the DASH diet (low sodium, more potassium from food), with salt likewise at no more than 5 g a dayHistory of kidney stones: drinking enough to pass about 2.5 L of urine a day is an evidence-based way to lower recurrence; limit sodium and oxalate at the same time, but do not limit calciumKidney disease plus an ACE inhibitor, , or spironolactone: do not take potassium on your own, and do not use potassium-chloride salt substitutes, because of the risk of high blood potassium
Exercise, heavy labor, heat
Under 60 minutes: plain water is enough60 minutes to 4 hours, in the heat: you can add some sodium (sports drinks or salt tablets), but do not drink to a scheduleEndurance events or heavy work in the heat over 4 hours:Body weight: losing 1–2% by the end is normalDrink to thirst, not mechanicallySodium plus a little sugar (what endurance exercise needs)Headache or nausea: stop drinking first; do not add more waterAround the race, as a precaution, go easy on ibuprofen-type painkillers
In practice · Urine color, salt swaps, when to get help
Check urine color: the handiest everyday feedback (around exercise, weighing yourself is more direct)Clear: you drank more than neededPale straw: about rightMedium yellow: drink a bit moreDark yellow or amber: you need fluidSlightly darker first-morning urine is normal; that is antidiuretic hormone at work overnight
Sodium and potassium in one line: cut sodium and raise potassium, not just cut sodium
Cutting sodium: less processed meat, less soy sauce, fewer salty snacks, less rice soaked in brothRaising potassium: bananas (about 400 mg in 1), potatoes (about 600 mg in 1), spinach (about 800 mg in 1 cooked cup), beans, tomatoes, avocadoIf you have chronic kidney disease, take an ACE inhibitor, , or spironolactone, or are very old, do not use potassium-chloride salt substitutes
The real picture for calcium and magnesium
Calcium: China's recommended nutrient intake () for adults is 800 mg a day; two national cohorts measured actual average intakes of only 451 and 484 mg a day, about 60% of itSources: milk, yogurt, tofu, sardines, high-calcium mineral waterIf food covers it, supplements are not neededMagnesium: China's recommended intake for adults is 330 mg a day; people who eat few whole grains, leafy greens, nuts, and beans easily fall shortSources: whole grains, leafy greens, nuts, beans, dark chocolateEvidence for supplements is limited: randomized-trial signals for heart disease, cramps, and migraine are all weakFood sources first
When to see a doctor
Sudden headache with confusion and nausea or vomiting (after an endurance event): suspect EAH and go to the emergency departmentLeg swelling that does not go away over a long period: get the heart, liver, and kidneys checkedThirsty no matter how much you drink, with frequent urination: get checked for diabetes and diabetes insipidusHigh blood pressure with stubborn swelling: see endocrinology and nephrology
A few last lines
Water is not nutritional magicDrinking enough is a low bar that most healthy adults already clearWhat really moves health is cutting sodium, raising potassium, and drinking fewer sugary drinks, far more than drinking more waterMost marketing talk only wastes money, but overdrinking during exercise carries a risk of death, and that one cannot be ignored
References · 22
- Institute of Medicine. (2005). Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. National Academies Press. nap.nationalacademies.org/catalog/10925/dietary-reference-intakes-for-water-potassium-sodium-chloride-and-sulfate
- Sawka, M. N., Burke, L. M., Eichner, E. R., Maughan, R. J., Montain, S. J., & Stachenfeld, N. S. (2007). American College of Sports Medicine position stand: Exercise and fluid replacement. Medicine & Science in Sports & Exercise, 39(2), 377-390. Abstract content: drink to prevent excessive dehydration (more than 2% body-weight loss from water deficit) and excessive electrolyte change; sweat rates and sweat electrolyte content vary considerably between individuals, so programmes should be customised, e.g. by weighing before and after exercise. The abstract gives no sweat sodium or potassium figures (abstract, PMID 17277604). 10.1249/mss.0b013e31802ca597
- Delicce, A. V., & Makaryus, A. N. (2023). Physiology, Frank Starling law. In StatPearls. StatPearls Publishing. www.ncbi.nlm.nih.gov/books/NBK470295
- Taghavi, S., Nassar, A. K., & Askari, R. (2025). Hypovolemia and hypovolemic shock. In StatPearls. StatPearls Publishing. www.ncbi.nlm.nih.gov/books/NBK513297
- González-Alonso, J., Crandall, C. G., & Johnson, J. M. (2008). The cardiovascular challenge of exercising in the heat. The Journal of Physiology, 586(1), 45-53. 10.1113/jphysiol.2007.142158
- van Wijck, K., Lenaerts, K., Grootjans, J., Wijnands, K. A. P., Poeze, M., van Loon, L. J. C., Dejong, C. H. C., & Buurman, W. A. (2012). Physiology and pathophysiology of splanchnic hypoperfusion and intestinal injury during exercise: strategies for evaluation and prevention. American Journal of Physiology-Gastrointestinal and Liver Physiology, 303(2), G155-G168. 10.1152/ajpgi.00066.2012
- Low, P. A., & Tomalia, V. A. (2015). Orthostatic hypotension: mechanisms, causes, management. Journal of Clinical Neurology, 11(3), 220-226. 10.3988/jcn.2015.11.3.220
- Hew-Butler, T., Rosner, M. H., Fowkes-Godek, S., Dugas, J. P., Hoffman, M. D., Lewis, D. P., Maughan, R. J., Miller, K. C., Montain, S. J., Rehrer, N. J., Roberts, W. O., Rogers, I. R., Siegel, A. J., Stuempfle, K. J., Winger, J. M., & Verbalis, J. G. (2015). Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015. Clinical Journal of Sport Medicine, 25(4), 303–320. Full text read 2026-09-24 (simultaneous BJSM publication, 49(22), 1432, via a Wayback snapshot of 10 October 2024; PubMed has no abstract, PMID 26102445): the single most important risk factor is sustained excessive intake of water, sports drinks or other hypotonic fluids beyond sweat, respiratory and renal losses; all sports drinks are hypotonic (sodium about 10-38 mmol/L), so overdrinking them is not protective. Using thirst to guide drinking should limit overdrinking while preventing excessive dehydration (Grade 1C); earlier advice to drink before thirst was meant for high sweat rates; fluid deficits up to about 3% of body mass are tolerated in cool to temperate conditions. Sodium supplements cannot prevent EAH when fluid intake is excessive (Grade 1C). Treatment: symptom severity, not the sodium value, guides therapy (Grade 1A); restrict hypotonic and isotonic fluids until urinating; severe EAH with encephalopathy gets an immediate 100 mL bolus of 3% NaCl, repeated up to twice (about 10-min intervals) if there is no improvement, without waiting for a lab value (Grade 1B); IV hypotonic fluids, lactated Ringer's or normal saline are contraindicated in confirmed dilutional EAH. Travel and meals for the panel were funded by CrossFit, Inc. 10.1097/JSM.0000000000000221
- Périard, J. D., Racinais, S., & Sawka, M. N. (2015). Adaptations and mechanisms of human heat acclimation: applications for competitive athletes and sports. Scandinavian Journal of Medicine & Science in Sports, 25(S1), 20-38. 10.1111/sms.12408
- Valtin, H. (2002). "Drink at least eight glasses of water a day." Really? Is there scientific evidence for "8 × 8"? American Journal of Physiology — Regulatory, Integrative and Comparative Physiology, 283(5), R993–R1004. Dartmouth nephrologist's narrative review finding no peer-reviewed evidence for the 8×8 oz/day rule and tracing it to a misread 1945 NRC recommendation that explicitly included water from food. 10.1152/ajpregu.00365.2002
- Thomas, D. T., Erdman, K. A., & Burke, L. M. (2016). American College of Sports Medicine joint position statement: nutrition and athletic performance. Medicine & Science in Sports & Exercise, 48(3), 543–568. The abstract has no g/kg numbers. Full text: protein intake to support metabolic adaptation, repair, remodelling and protein turnover generally ranges from 1.2 to 2.0 g/kg/day, with higher intakes for short periods of intensified training or reduced energy intake; about 0.3 g/kg after key sessions and every 3-5 hours over multiple meals (full text, MSSE page via Wayback snapshot 7 March 2026). 10.1249/MSS.0000000000000852
- World Health Organization. (2006). Oral rehydration salts: production of the new ORS. WHO Press. iris.who.int/handle/10665/69227
- Almond, C. S., et al. (2005). Hyponatremia among runners in the Boston Marathon. The New England Journal of Medicine, 352(15), 1550–1556. 2002 Boston Marathon: 766 enrolled, 488 gave a usable finish-line sample. Hyponatraemia (serum sodium <= 135 mmol/L) in 13%, critical (<= 120 mmol/L) in 0.6%. On multivariate analysis it was associated with weight gain (OR 4.2), racing time > 4:00 h (OR 7.4) and BMI extremes; female sex, the composition of fluids ingested (sports drink vs water) and NSAID use were not (abstract, PMID 15829535). 10.1056/NEJMoa043901
- Schwellnus, M. P. (2009). Cause of exercise associated muscle cramps (EAMC) — altered neuromuscular control, dehydration or electrolyte depletion? British Journal of Sports Medicine, 43(6), 401–408. Systematic review concluding that the dominant mechanism for exercise-associated muscle cramps is altered neuromuscular control from muscle fatigue, not dehydration or electrolyte depletion as previously assumed. 10.1136/bjsm.2008.050401
- National Institutes of Health, Office of Dietary Supplements. (2022). Magnesium — Fact Sheet for Health Professionals. ods.od.nih.gov/factsheets/Magnesium-HealthProfessional
- Price, A., Burls, A. (2015). Increased water intake to reduce headache: learning from a critical appraisal. Journal of Evaluation in Clinical Practice, 21(6), 1212-1218. NOT a Cochrane review and not a systematic review — it is a critically-appraised-paper teaching exercise on ONE trial (Spigt 2012, n=102). That trial improved subjective migraine quality of life but did not reduce headache days. 10.1111/jep.12413
- National Academies of Sciences, Engineering, and Medicine. (2019). Dietary Reference Intakes for Sodium and Potassium. National Academies Press. The PubMed book abstract (PMID 30844154) gives no reference values; it says the report updates the sodium and potassium DRIs with an expanded model that adds chronic-disease endpoints (the Chronic Disease Risk Reduction Intake). The numeric AIs and CDRRs were not re-read for this note (abstract). www.ncbi.nlm.nih.gov/books/NBK538102
- National Institutes of Health, Office of Dietary Supplements. (2021). Potassium — Fact Sheet for Health Professionals. ods.od.nih.gov/factsheets/Potassium-HealthProfessional
- National Health and Family Planning Commission of the People's Republic of China. (2018). Chinese dietary reference intakes - Part 2: Macro-elements (WS/T 578.2-2018). Health industry standard, issued 2018-03-06, effective 2018-08-01; drafted by the Chinese Nutrition Society with the National Institute for Nutrition and Health, China CDC. Table 1, adults aged 18 and over: calcium EAR 650 mg/d, RNI 800 mg/d, UL 2000 mg/d (RNI rises to 1000 mg/d from age 50); sodium AI 1500 mg/d at 18-49, falling to 1400 mg/d at 50-79 and 1300 mg/d at 80+; potassium AI 2000 mg/d; magnesium RNI 330 mg/d; phosphorus RNI 720 mg/d. Note that this AI is the adequate-intake figure and is a different DRI category from the proposed intake for preventing non-communicable disease. www.nhc.gov.cn/wjw/yingyang/201805/f2c614be95fe41dba8123c23a6e6fb55/files/1739783539207_73894.pdf
- Guo, X., Gao, J., Meng, X., Wang, J., Zhang, Z., Song, Q., Hu, K., Sun, C., & Li, Y. (2021). Association of dietary calcium intake with bone health and chronic diseases: two prospective cohort studies in China. Frontiers in Nutrition, 8, 683918. Two nationally representative Chinese cohorts - the Harbin Cohort Study on Diet, Nutrition and Chronic Non-communicable Disease (n = 6,499, mean 4.2-year follow-up) and the China Health and Nutrition Survey (n = 8,140, mean 5.3-year follow-up), both restricted to adults free of chronic disease at recruitment. Mean dietary calcium intake was 451.35 +/- 203.56 mg/day in the Harbin cohort and 484.32 +/- 198.61 mg/day in CHNS. NOTE the null findings, which are the part most easily dropped when this record is cited for the intake figures: calcium intake was NOT significantly associated with bone mineral density (p = 0.110), nor with type-2 diabetes or cardiovascular disease; the inverse association with incident obesity disappeared once vegetable intake was added to the model. 10.3389/fnut.2021.683918
- World Health Organization. (2012). Guideline: Sodium intake for adults and children. World Health Organization. Recommends a reduction to less than 2 g/day of sodium (5 g/day of salt) in adults - a strong recommendation. For children, the recommended maximum adult level of 2 g/day sodium should be adjusted downward based on the energy requirements of children relative to those of adults. www.who.int/publications/i/item/9789241504836
- World Health Organization. (2012). Guideline: Potassium intake for adults and children. World Health Organization. Recommends an increase in potassium intake from food to reduce blood pressure and the risk of cardiovascular disease, stroke and coronary heart disease in adults (strong recommendation), and suggests a potassium intake of at least 90 mmol/day (3,510 mg/day) for adults (conditional recommendation); for children the 90 mmol/day should be adjusted downward based on energy requirements (guideline text, WHO IRIS PDF, read 2026-09-24). www.who.int/publications/i/item/9789241504829