From controlling body temperature and flushing out toxins, adequate hydration plays a vital role in our general health and well-being, water is a life essential. However, while dehydration garners significant attention, overhydration, or drinking excessive amounts of water, is a condition that can have serious and sometimes fatal consequences.

Although it may sound bizarre since drinking water is said to be the solution for most health related problems it is important to recognize how much water is considered "too much" or the risks involved with being overhydrated can maintain a healthy balance.

What Is Water Intoxication?

Water intoxication, also termed hyperhydration, water poisoning or water toxemia, develops when an individual drinks much more water than the kidney can excrete. The main function of the kidneys in the human body is the processing and excretion of excess water. However, the human kidneys can process only up to 0.8 to 1.0 liters of water at a time. Drinking an amount that exceeds this may overwhelm the kidneys and put the electrolyte balance out of sync in the human body.

Electrolytes, especially sodium, are essential in maintaining fluid balance within and outside cells. Hyponatremia is the condition when sodium levels fall below 135 mmol/L, resulting from excessive water intake. This causes water to shift into cells, swelling them. In the brain, this can cause severe complications, including coma or even death.

Symptoms of Water Intoxication

The symptoms of water intoxication vary from mild to severe. Early symptoms are often similar to dehydration, which makes self-diagnosis challenging. Common symptoms include:

• Headaches
• Nausea and vomiting
• Muscle cramps or weakness
• Fatigue or drowsiness
• Confusion and disorientation

In more serious cases, water intoxication can cause seizures, loss of consciousness, or swelling in the brain. These complications can be fatal if left untreated.

A notable case occurred in 2007 when a woman participating in a water-drinking contest tragically died after consuming nearly two gallons of water in under two hours. More recently, actress Brooke Shields experienced a grand mal seizure attributed to excessive water consumption.

Causes of Water Intoxication

Water intoxication is rare, but certain scenarios can increase the risk:

1. Sporting Events and Endurance Training

These endurance athletes are prone to water intoxication, especially if they drink large amounts of water without replacing lost electrolytes. Hyponatremia usually happens during long races or marathons as individuals mistake fatigue and muscle cramps for dehydration and continue drinking water in excess.

2. Military Training

Overhydration among military personnel is usually due to severe physical activity in extreme environmental conditions. The total number of hyponatremia cases documented from 2007 through 2022 for the active duty in the United States exceeds 1,600, with a note to this problem on exertion-related overhydration.

3. Mental Health Conditions

Compulsive water drinking, known as psychogenic polydipsia, is linked with some mental illnesses such as schizophrenia and psychosis. People with these conditions tend to drink too much water, causing a hazardous electrolyte imbalance.

4. Drug Abuse

Drugs such as MDMA (ecstasy) raise the body temperature and make people thirsty, and at times, some people tend to drink excess water at events like music festivals. MDMA also leads to urine retention, thus exacerbating the dangers of water intoxication.

How Much Water Is Too Much?

The exact amount of water that causes intoxication varies from one person to another. However, drinking more than 1 liter of water per hour for several hours raises the risk. For healthy individuals, the risk of overhydration is low unless taking part in extreme physical activity or ignoring thirst cues.

Certain medical conditions, such as kidney or liver disorders, can impair the body's ability to process fluids, and even moderate water intake may be harmful. Similarly, certain medications, such as diuretics and antipsychotics, can affect the perception of thirst or fluid regulation.

How Much Water Is Enough?

The widely touted recommendation of eight 8-ounce glasses of water per day has little basis in fact. According to the National Academy of Medicine, a daily total fluid intake is about 15 cups (3.7 liters) for males and 11 cups (2.7 liters) for females, from beverage sources and from food. Usually, about 20 percent of daily hydration comes from foods such as fruits and vegetables.

A better rule of thumb is to listen to your body and drink water based on thirst. Use the color of your urine as an indicator:

• Light yellow urine indicates proper hydration.
• Dark yellow urine may indicate dehydration.

Older adults, whose thirst mechanisms may decline with age, should be proactive about maintaining hydration, especially during illness or hot weather.

Water Intoxication vs. Dehydration

The symptoms of water intoxication—such as headaches, fatigue, and muscle weakness—are similar to those of dehydration. If you are unsure which condition you are experiencing, seek medical attention immediately rather than self-treating with more water.

Preventing Water Intoxication

To avoid the dangers of overhydration:

• Drink water gradually throughout the day rather than consuming large amounts at once.
• Replace lost electrolytes post high-intensity exercise or heavy sweating.
• Consider using sports drinks or salty snacks to help replenish sodium.
• Keep track of fluid consumption during long-duration activities, and do not consume more water than the body is losing in terms of electrolytes.
• If on medications or have specific medical conditions, check with your doctor regarding the safety of drinking water.

For signs of severe water intoxication-including confusion, drowsiness, seizures, and loss of consciousness-customer is advised to seek medical assistance immediately. In the meanwhile, a salty snack would help to temporarily correct low sodium levels.

Hydration is important to health, but overhydration can be a serious risk; the secret is in finding a balance. Drink enough water to satisfy your body, but not so much that it overwhelms your system. Remember, water is life, but moderation keeps it that way.

Hyponatremia (low sodium level in the blood). National Kidney Foundation. 2023.

Water Toxicity. NIH. 2023

Exercise-Associated Hyponatremia: 2017 Update. Front Med (Lausanne). 2017

Update: Exertional Hyponatremia Among Active Component Members of the U.S. Armed Forces, 2007–2022

NBC News producer Susan Kroll, 58, initially attributed her occasional difficulty remembering words to menopause-related brain fog. However, tests revealed an elevated genetic risk of Alzheimer’s disease and abnormal amyloid levels in her brain.

Her journey began when she sought a diagnosis for her mother, who had started experiencing memory problems at 75. While helping her mother, Kroll decided to investigate her own risk after learning that Alzheimer’s risk can be genetic, she wrote on Today.com.

Genetic Testing Revealed An Elevated Alzheimer’s Risk

Testing showed that Kroll’s mother carried two copies of a gene called APOE4. Everyone inherits one APOE gene from each parent. The three common variants are APOE2, which may reduce Alzheimer’s risk; APOE3, the most common variant, which has a neutral effect; and APOE4, which increases the risk.

According to the Mayo Clinic, people with two copies of APOE4 are eight to 12 times more likely to develop Alzheimer’s.

To understand her own risk, Kroll took a cheek-swab genetic test in October 2024.

"I had an APOE4 and APOE3 gene, making me two to three times more likely to develop Alzheimer’s. I was a bit relieved," Kroll wrote.

Also read: Normal Ageing or Alzheimer's? Doctors Explain Six Key Differences to Watch For

Blood Tests And Brain Scans Revealed More

In May 2025, Kroll took a blood test developed to help diagnose Alzheimer’s disease, which had recently been cleared by the US Food and Drug Administration (FDA).

The test measures certain proteins, including a specific form of tau, that can indicate the presence of amyloid plaques in the brain. These protein deposits are considered a hallmark of Alzheimer’s disease.

Kroll said her "results were well outside the normal range". She had also noticed occasional difficulty remembering words, which she had initially attributed to menopause-related brain fog.

She was given personalised recommendations covering diet, exercise, supplements and sleep.

Diet, Exercise And Sleep Changes To Support Brain Health

Kroll made several changes to her daily routine.

"I cut out artificial sweeteners and limited fried and processed foods, red meat, cheese, sweets and alcohol. Every day, I started eating leafy greens, whole grains, veggies and fruit, and every week multiple servings of fish, walnuts, almonds, avocado and berries."

She also intensified her workouts, doing 45–60 minutes of cardio three to four days a week, alongside strength training. She focused on three muscle groups, completing three sets of each exercise with eight to 10 repetitions. She also started going to bed earlier.

Read More: India Gets Its First Alzheimer’s Drug: Know All About Eli Lilly’s Lormalzi

Kisunla Infusions Reduced Amyloid Levels In Her Brain

In December 2025, Kroll began treatment with Kisunla, an anti-amyloid infusion approved by the FDA in 2024.

A previous brain scan had shown elevated amyloid levels in every quadrant of her brain. Clinical trials have shown that Kisunla can slow cognitive and functional decline in eligible patients.

After six infusions, Kroll underwent another brain scan in May 2026 to assess her progress.

Her amyloid score dropped from 86 to four. The radiologist noted, "The amyloid issue has resolved."

Further blood tests showed that her tau levels were normal. Kroll suggested that her dietary changes may have contributed to this result.

Does She Still Have An Elevated Alzheimer’s Risk?

Kroll currently has neither Alzheimer’s disease nor mild cognitive impairment. However, she continues to have positive biomarkers and an elevated genetic risk. She believes the "early interventions helped slow down or potentially stop the progression of changes years before they could worsen".

Her journey is far from over. She continues to receive care at the Alzheimer’s Prevention Clinic, where her blood and biomarkers are monitored monthly.

Obesity drugs such as semaglutide and tirzepatide may offer benefits beyond weight loss and blood sugar control. Researchers say these medicines could also help protect brain function, including memory and other cognitive abilities.

Researchers from the University of Gothenburg and the University of Copenhagen examined evidence on how these drugs affect the brain and their potential to inform treatments aimed at preserving cognitive function. The review was published in the journal Science.

How Do Obesity Drugs Affect The Brain?

Semaglutide and tirzepatide belong to a class of medicines that act on metabolic pathways involved in appetite and blood sugar regulation. They may also influence biological processes important for brain function.

Animal studies suggest that GLP-1 drugs can affect learning and memory. However, findings from human studies have been mixed.

Studies analysing patient records have linked GLP-1 treatment to a lower risk of dementia among people with type 2 diabetes. However, these findings do not establish whether the medicines themselves are responsible for the reduced risk.

Semaglutide Failed To Slow Alzheimer's Progression

The potential benefits of these drugs have also been examined in people with Alzheimer's disease.

In Novo Nordisk's EVOKE and EVOKE+ clinical trials, semaglutide did not slow disease progression in patients with early Alzheimer's disease, despite producing changes in several biological markers associated with the condition.

However, researchers say these findings do not rule out potential benefits in other groups of patients.

People with obesity or type 2 diabetes may experience difficulties with attention, planning and processing speed. These cognitive problems are often associated with metabolic and vascular health, making them potential targets for treatment.

Stina Börchers, first author of the review and a researcher affiliated with the University of Gothenburg and the University of Copenhagen, said it is important to establish whether these treatments can help preserve cognitive abilities, particularly when started before problems become established.

“We need to find out whether these treatments can help people with obesity or diabetes preserve their cognitive abilities, particularly if treatment begins before cognitive problems become established,” Börchers said.

Could Obesity Drugs Lead To New Brain Treatments?

Researchers are trying to understand whether the potential effects of obesity medicines on the brain result from improved metabolism, direct action on the brain, or a combination of both.

Christoffer Clemmensen, senior author of the review and research group leader at the University of Copenhagen, said advances in obesity medicines offer new opportunities to understand how metabolic regulation influences brain function.

“By disentangling the direct and indirect effects of these drugs on the brain, we may ultimately be able to develop treatments specifically aimed at preserving cognitive function,” Clemmensen said.

Why More Clinical Trials Are Needed

The researchers are calling for clinical trials that assess memory and other cognitive abilities from the beginning of treatment.

They also stress the need to monitor older and frail patients. Rapid weight loss and loss of muscle mass could affect physical function and potentially reduce the benefits of treatment in these groups.

For now, whether obesity drugs can help preserve cognitive function remains an important research question. More clinical evidence is needed before they can be considered treatments for protecting brain health.

For 25-year-old Kaela Knight, a nail artist from Colorado, taking tirzepatide, the active ingredient in Eli Lilly's Mounjaro and Zepbound, brought an unusual side effect: skin so sensitive that even a light touch hurt.

Knight started treatment in September 2024 at 210 pounds and eventually reached 125 pounds. But during her second month, as her dose increased from 2.5 mg to 5 mg, she began experiencing burning sensations.

"I always describe it as feeling like a sunburn without any visible redness or irritation," she told the Daily Mail.

The sensation affected her hips, forearms and neck. Episodes lasted 24–48 hours, although some persisted for about a week.

Other patients taking Novo Nordisk's Ozempic and also Mounjaro have reported similar experiences.

Known as allodynia, this nerve-pain condition makes normally harmless sensations, such as clothing brushing against the skin or a light touch, painful. Patients describe it as a sunburn without visible redness or irritation.

Although it is not an established side effect of Ozempic, Wegovy, Mounjaro or Zepbound, medical reports have documented similar symptoms. A direct link remains unproven.

"I have [areas] all over that are burning. It's driving me nuts," one Reddit user wrote. Another said painkillers and lidocaine gels offered little relief.

Some patients report improvement after reducing their dose or stopping treatment.

Also read: Ozempic Hair: GLP-1 Drug Use Linked To 7% Higher Baldness Risk In Men

Why Could Weight-Loss Injections Cause Burning Skin?

Semaglutide, used in Ozempic and Wegovy, mimics the GLP-1 hormone. Tirzepatide, used in Mounjaro and Zepbound, targets GLP-1 and GIP receptors.

Dr Richard Siegel, an endocrinologist at Tufts Medicine, told the Daily Mail that these drugs could potentially affect nerve signalling through the brain and spinal cord.

Another theory involves changes in the fat layer beneath the skin during weight loss, which could affect nerve sensitivity. Neither explanation has been proven.

What Do Medical Reports Reveal?

An October 2025 report documented two cases:

• A 56-year-old woman developed painful skin sensations after switching to semaglutide 2.4 mg. Symptoms resolved without treatment after six weeks.
• A 75-year-old man with type 2 diabetes developed widespread burning after switching to tirzepatide. Symptoms resolved after he discontinued it and returned to oral semaglutide.

Some patients report improvement over time or after reducing their dose.

Dr Siegel said symptoms can last days to weeks, potentially becoming less noticeable as the body adjusts to treatment, much like nausea and constipation.

"It's possible something similar is happening here, where temporary changes in receptor activity alter nerve signaling at first, but become less noticeable as the body adjusts," he said.

Read More: Stopping Ozempic, Wegovy, Mounjaro Linked To 22% Higher Heart Attack, Stroke Risk: Study

Newer Weight-Loss Drugs May Carry A Higher Risk

Clinical trials have also recorded dysesthesia, a broader category of abnormal sensations, including burning and tingling. It is not necessarily the same as allodynia.

In a high-dose oral semaglutide trial, dysesthesia occurred in fewer than 3% of 334 participants, compared with none receiving placebo.

Phase 3 trials of retatrutide, an experimental drug targeting GLP-1, GIP and glucagon receptors, reported:

• 9 mg dose: 8.8%
• 12 mg dose: 20.9%
• Placebo: 0.7%

Who Is More Vulnerable To Allodynia?

Risk factors remain unclear. Dr Siegel believes higher doses could play a role.

"As best as I can tell, it would mostly be people on higher doses of these medications," he said.

He also suggested that people with greater pain sensitivity, including those with fibromyalgia, might be more susceptible.

What Should Patients Do?

Patients experiencing unusual skin burning or sensitivity should consult their doctor. Dose adjustments or alternative treatments may be considered, but medication should not be changed or stopped without medical advice.

Allodynia can also occur with shingles, migraines and nerve damage, so symptoms should not automatically be attributed to weight-loss drugs.

Dr Siegel recommends recording when symptoms occur, where they appear and what makes them better or worse.

Persistent or worsening pain should be medically evaluated.