Overhydration: Can You Drink Too Much Water?


Water is essential for all bodily cells to function properly. Overhydration is a problem that occurs when you drink too much water. Dehydration’s negative consequences on mental and physical health are well-known. Consequences of overhydration, on the other hand, are less well recognized.

There is no one-size-fits-all formula for determining how much water you should drink on a daily basis. The widely accepted suggestion of eight glasses each day is an excellent place to start. Depending on your environment, exercise regimen, overall health, and situations such as pregnancy or nursing, you should adapt your intake around this level.

What Causes Overhydration?

Water poisoning, also known as overhydration, can develop for a variety of causes. In general, drinking too much water too rapidly might cause dehydration. It can also happen if your body holds on to too much water.

This sort of dehydration is caused by medical issues. Overhydration can be exacerbated by kidney issues, hormonal abnormalities, and diabetes. Overhydration can also be caused by psychiatric illnesses like psychogenic polydipsia. 

Overhydration is a serious problem for endurance athletes. They frequently consume excessive amounts of water prior to or following a triathlon or similar event. That is why it is critical to pay attention to your body and hydrate properly.

Overhydration presents itself in the following ways:

  • Heart, kidney and liver problems. Fluid accumulation in the body is caused by congestive heart failure and some disorders of the kidneys or liver, which dilutes sodium in the body and lowers the overall level. Any fluid overload taken (above osmoregulatory demand) is quickly eliminated by the body in people with proper kidney function.
  • Syndrome of inappropriate antidiuretic hormone (SIADH). In this condition, high levels of the inappropriate anti-diuretic hormone (ADH) are produced, causing your body to retain water instead of excreting it normally in your urinary excretion.
  • Drinking too much water. Excessive water consumption can induce low sodium levels by obstructing the kidneys’ capacity to eliminate water. Drinking too much water excretion during endurance events, such as marathons and triathlons, might dilute the sodium concentration of your blood because you lose sodium through sweat.
  • Hormonal changes. Adrenal gland insufficiency (Addison’s disease) affects your adrenal glands’ ability to produce hormones that help maintain your body’s balance of sodium, potassium and water channels. Low blood salt levels can also be caused by low thyroid hormone levels.

What Happens When You Drink Too Much Water?

You may get water poisoning, intoxication, or a change in brain function if you consume too much water. This occurs when the cells (including brain cells) contain too much water, causing them to expand. When brain cells swell, pressure is created in the brain. Confusion, sleepiness, and headaches are all possible side effects. If this pressure rises, it can lead to hypertension (high blood pressure) and bradycardia (slow heart rate) (Low Heart Rate).

The electrolyte sodium is the most affected by dehydration, resulting in hyponatremia. Sodium is a necessary component for maintaining the equilibrium of fluids in and out of cells. Fluids go within the cells when its levels drop due to a large amount of water in the body surface. The cells then inflate, placing you at danger of suffering seizures, coma, or even death.

Are There Different Types of Overhydration?

Overhydration can be divided into two categories:

Increased water intake

This happens when you drink more water than your kidneys can expel in your urine. This can lead to a build-up of water in your bloodstream.

Retaining water

When your body is unable to effectively eliminate water, this condition develops. Your body may retain water due to a number of medical conditions.

Both of these varieties are harmful because they disrupt the blood’s sodium-water balance.

Who Is At Risk For Overhydration?

Endurance athletes, who drink a lot of water before and during their activities, are more prone to overhydration. It was reported by the following individuals:

  • runners who compete in marathons and ultramarathons (races longer than 26.2 miles)
  • Triathletes who have completed an Ironman race
  • cyclists that ride for long periods of time
  • Players of rugby
  • rowers of the highest caliber
  • Military personnel taking part in training exercises
  • hikers

This condition is more common in those who have difficulties with their kidneys or liver. It can also impact patients who are suffering from decompensated heart failure.

How Can You Prevent Overhydration?

By weighing yourself before and after a race, endurance athletes can lower their risk of overhydration. This makes it easier to figure out how much water they’ve lost and how much they need to replace. It is suggested that for every pound lost, you drink 16 to 20 ounces of water.

While exercising, drink 2 to 4 cups of water per hour. Sports beverages are also a possibility if exercising for more than an hour. Sugar is present in these drinks, as well as electrolytes like sodium and potassium, which are lost through sweat. When exercising, let thirst be your guide. Drink a lot more if you’re thirsty.

Treatment of Overhydration

  • Consumption of fluids is restricted.
  • Treatment for the underlying cause of dehydration

Whatever the cause of dehydration, fluid intake must usually be limited (but only as advised by doctors). Drinking less than a quart of fluids per day usually leads in a few days of improvement. Restricting sodium consumption is also beneficial if overhydration occurs due to high blood volume due to heart, liver, or renal problems, because sodium promotes the body to retain water.

Drugs that cause dehydration are no longer used. Doctors may give diuretics to enhance salt and water excretion in the urine. Other medications that enhance water excretion are occasionally used to treat overhydration when blood volume is normal. When a person is in the hospital, these medicines are commonly utilized and can be closely monitored.

What Is Water Intoxication?

Water intoxication, often known as water poisoning, is a disruption of brain function induced by consuming too much water. The amount of water in the blood increases as a result. This can dilute electrolytes in the sodium in blood.

Hyponatremia is a condition in which sodium levels fall below 135 millimoles per liter (mmol/l). Sodium keeps the fluid balance inside and outside of cells in check. Fluids migrate from the exterior to the inside of cells when sodium levels drop owing to excessive water consumption, causing them to expand.

This can be serious and even life-threatening when it happens to brain cells. Drinking too much water causes water intoxication. Excess water dilutes the salt in the blood, allowing fluids to flow inside cells and enlarge them.

Symptoms of Overhydration

Overhydration and low salt levels in the blood are especially dangerous for brain cells. When overhydration is modest or moderate, brain cells have time to adapt, resulting in only mild symptoms (if any) such as distractibility and fatigue. Vomiting and problems with balance emerge when overhydration starts quickly. Confusion, convulsions, or coma may occur if overhydration becomes worse.

When blood volume is normal and overhydration occurs, the excess water normally goes into the cells, resulting in tissue swelling (edema). Fluid overload can collect in the lungs and lower legs when excess blood volume occurs.

It’s crucial to figure out whether dehydration, as measured by body composition monitor measurements, is a independent predictor of survival. In addition, the average occurrence of intradialytic adverse events was assessed for each HD population.

Fluid status is difficult for clinical assessment, putting patients at risk for hypovolemia, intradialytic hypotension, and loss of residual renal function, or persistent overhydration, which manifests as large interdialytic weight gain, hypertension, left ventricular hypertrophy, and peripheral and pulmonary oedema.

The Mortality Risk of Overhydration in Haemodialysis Patients

In end-stage renal failure (ESRF), overhydration is caused by an excess of salt and water, as well as diminished muscle mass and altered body composition linked with comorbidity and inflammation.

This study highlights the known data on the physiology, psychology, and pathophysiology of overhydration acquired from both animal (mainly rodent) and human studies.


While cardiovascular events continue to be the leading cause of death and remain the primary form of mortality in haemodialysis (HD) patients , few facilities are aware of the importance of hydration status (HS). Previous study shows on how to see the severity of the current overhydration affects long-term survival. Despite the fact that these randomized trials accept the bioimpedance analyses’ efficacy for dry weight assessment in HD patients. The goal of this study was to look into and quantify a potential link between hydration and death risk in chronic HD patients.


We used a body composition monitor (BCM) to analyzethe assessment of hydration status and body composition in 269 prevalent HD patients (28 percent diabetics, dialysis vintage = 41.2 70 months) in three European centers. After a 3.5-year follow-up period, these patients’ survival was determined. The criterion for defining hyperhydration was chosen at 15% relative to extracellular water (ECW), which corresponds to a 2.5-liter surplus of ECW. For a set of demographic data, comorbid conditions, and other factors, Cox-proportional hazard models were employed to compare survival based on baseline hydration status.


For all patients, the median hydration state (HS) before HD therapy (HSpre) was All patients had an uncorrected gross yearly annual mortality of 8.5 percent. The hyperhydrated subgroup (n = 58) presented ΔHSpre = 19.9 ± 5.3% and a gross mortality of 14.7%. The Cox adjusted hazard ratios revealed that age systolic blood pressure and unadjusted analysis of relative hydration status were the only a significant predictors of mortality in our patient population (95 % confidence interval for mortality odds ratio, risk ratio, or hazard ratio).

Data was extracted at the individual study level, utilizing the current study population summaries (on Microsoft Word 2011), as well as in the form of review summary tables (on Excel 2011). There were no a priori assumptions about data quality.

Design, setting, participants and measurements

Using a previously reported cut-off impact of overhydration as well as a new cut-off value determined from our study of this specific cohort, a prospective cohort trial was conducted to assess the influence of absolute overhydration on all-cause mortality and cardiovascular events (CVE).

Bioimpedance was used to assess the body fluid composition of 221 HD patients from a single center at the start of the study. Supplemental echocardiography was conducted on 157 individuals (echocardiography subgroup). The relative fluid overload (RFO) cut-off points were 15 percent and 17.4 percent, respectively, in a comparative survival study (a value determined by statistical analysis to have the best predictive value for mortality in our cohort).

Lab tests, antihypertensive medication and instrumental tests

Serum albumin, haematocrit, urea, serum creatinine, and serum inorganic phosphates were measured in the latest monthly lab data before starting the BCM medication. The amount of antihypertensive medications (AHT) was also counted, including diuretics and pharmaceuticals used for cardioprotection.

In the study’s participating centers, chest x-rays are not frequently conducted. As a result, the patients did not have access to a cardiothoracic ratio.


The parameters’ mean values and frequencies were compared using ANOVA or the chi square test, if appropriate. The significance threshold was set to P 0.05. The Kaplan–Meier technique was used to describe survival functions based on baseline hydration status. For univariable comparisons, the log-rank test was utilized.

A two-tailed Wald test was used to analyze the contribution of variables to explaining the dependent variable, with P 0.05 considered significant. The complementary log minus log plots were used to check the proportion hazard assumption for each model. The SPSS software, version 15, was used for all statistical analyses (SPSS Inc., Chicago, IL, USA).


Diabetes, cardiovascular disorders (cardiac insufficiency, atrial fibrillation, ischemic heart disease, coronary artery disease), kidney disease (chronic kidney disease) and peripheral vascular disease were among the comorbidities identified (PVD). In chronic disease HD patients secondary, hydration status is an important and independent predictor of death, next only to the presence of diabetes.


Water makes up a major component of the body water and is essential for cell function and survival. When your body requires more water, it will notify you. Drinking too much alcohol might lead to fatal consequences. If you’re not sure how much water you should drink each day, go with the standard recommendation of eight glasses.