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

Four-year-old Sienna Dunion had initially flu-like symptoms, however her condition rapidly worsened, leading to a coma. What seemed like a simple flu was actually Acute Necrotising Encephalitis (ANE), a rare and severe brain disorder. After undergoing multiple surgeries and having removed 60% of her intestines, she is now struggling to walk and talk like from before.

How Did It Begin?

The first indication, which was very easy to miss was when she asked to return home five minutes after heading out to play with her scooter, reports The Independent. She had always been happy and exciting, so for her to return home so soon was not normal. She had also complained about feeling "cold and chilly" to her older sister, however, all of such symptoms were just seen as a common cold or flu signs.

As a result, her parents, Gary and Angelina Dunion, decided to keep her off school on Monday 17 November. Her temperature raised, no one was really concerned. All of these were cold and flu symptoms. She was still playing with her Barbies.

But it was on a Wednesday morning when she became unresponsive and had to make an emergency trip to A&E in Kettering. This is when she was induced into coma and diagnosed with the rare brain disease ANE.

Three weeks later, her family is facing the challenges to cope with the new changes which may take away how her daughter was before. Now, she requires years of intense rehabilitation to learn how to walk and talk again.

What is Acute Necrotising Encephalitis (ANE)?

Acute necrotizing encephalopathy (ANE) is a rare and serious brain condition that can cause sudden and rapid neurological decline after a viral infection, most often the flu or COVID-19. Because only a small number of cases have been reported worldwide, there is no standard treatment, making diagnosis and management especially difficult.

Sienna's father told The Independent, "For us, it’s really important that people can understand this has happened to a really healthy four-year-old girl who had no underlying issues. It has completely changed our lives overnight. What started as a flu has turned into a complicated brain disease and the last three weeks have just been horrendous.”

A Rare Diagnosis, But Urgent Care

Sienna had been feeling unwell on Monday and Tuesday, but it was on November 19 that her condition suddenly worsened. Her mother, Mrs Dunion, became alarmed when she tried to wake her and realised Sienna was unresponsive.

At A&E, doctors initially believed she was dehydrated after she tested positive for influenza. However, a CT scan showed unusual findings, including white lesions, while other test results remained unclear.

By 11 pm, doctors decided Sienna needed to be moved to the intensive care unit at Nottingham’s Queen’s Medical Centre. An MRI scan later confirmed a diagnosis of acute necrotising encephalopathy (ANE), a rare condition linked to viral infections.

Because of how uncommon the disease is, doctors designed a personalised treatment plan for her. This included plasma exchange, a procedure her family described as effectively washing her brain.

On Saturday, November 22, an ultrasound revealed a large build-up of fluid in her stomach. Sienna had to undergo emergency surgery, during which 60 per cent of her intestines were removed. Her father called it the hardest night of his life.

She later needed two more surgeries after air was found in her abdomen. Sienna now has a stoma bag and will live with short bowel syndrome for the rest of her life.

“The one thing doctors have been clear about is that she will not be the same when she fully wakes up,” Mr Dunion said. “She will need extensive rehabilitation.”

Although Sienna is awake, her father explained that she does not understand what is happening around her. She is weak, struggles to track with her eyes, and cannot eat on her own. The family is now fundraising to support her rehabilitation, including physiotherapy, speech and language therapy, feeding support, and changes needed at home.

A family struggling to cope

The couple also have a seven-year-old daughter, who is very close to Sienna. “They are best friends,” Mr Dunion said. “She keeps asking, ‘Where is Sienna? When can we be a family again?’”

He added that it is impossible to explain the seriousness of the situation to her. “I can’t tell her that she won’t be able to talk to her sister for a long time.”

“She was the most caring, easygoing four-year-old I’ve ever known,” her father said. “Even when she had a fever, she would check our temperature to make sure we were okay.”

He described her as a social child who loved being around other kids and had an infectious belly laugh. “We just don’t know if we’ll hear that laugh again,” he said.

The last thing anyone hopes to unwrap this Christmas is a heavy dose of flu. Yet as hospital admissions linked to the virus climb to levels not seen since 2010, this winter’s flu surge has pushed the NHS into what officials are calling a “worst-case scenario.”

Infections have jumped by over 50 per cent in just one week, and health leaders say there is still no clear peak. On average, 2,660 people a day were occupying hospital beds with flu last week, the highest figure ever recorded for this point in the season. Data from the UK Health Security Agency show the highest infection rates among children aged five to 14, followed closely by young people between 15 and 24. A number of schools have temporarily closed to curb outbreaks, while NHS leaders have advised people to consider wearing masks at work or on public transport, echoing guidance seen during the Covid years.

What Is Super Flu?

The strain driving the current spike has picked up the nickname “super flu” because it is believed to be a mutated form of influenza A (H3N2), known as “subclade K.”

Influenza H3N2 does not circulate as often as some other flu strains. Dr Simon Clarke, associate professor of cellular microbiology at the University of Reading, explains that the letters “H” and “N” refer to two proteins found on the virus surface, haemagglutinin and neuraminidase. “The numbers simply tell us which versions of those proteins are present,” says Dr Clarke. “It’s a way of grouping strains. This year, H3N2 happens to be the one in the lead.”

“H3 subtypes are relatively uncommon,” he adds. “That means fewer people have built up immunity. There is also evidence they spread more easily and mutate faster, which makes them harder for vaccines to keep up with.

“What we are seeing now is the outcome of that: cases rising sharply earlier than usual, with numbers likely to climb further as winter goes on.”

How Does Super Flu Differ From The Usual Variety?

Broadly speaking, flu falls into three main groups, A, B and C, according to Professor Ed Hutchinson from the Glasgow Centre for Virus Research. “Types A and B are the ones that make people seriously ill each winter. Influenza C circulates too, but it rarely causes severe disease. They are related, but not closely enough that immunity to one protects against the others,” he explains.

The concern is not that the virus has suddenly become far more deadly. Many people will catch it and recover without major problems. “The issue is scale,” Hutchinson says, as reported by The Telegraph. “When a virus spreads widely, even a small proportion of severe cases quickly adds up. That is what puts pressure on individuals and on the NHS.”

Last week, around 1,700 flu patients were in hospital, a 63 per cent increase on the previous week and more than 50 per cent higher than the same period last year. This rise is partly linked to a particularly aggressive subtype of the circulating H3N2 virus. “This strain is appearing earlier and spreading faster than we would expect, and immunity levels in the population are lower than usual for this stage of the season,” says Dr Aslam.

Is The Flu Shot Effective Against Super Flu?

Recent figures suggest the flu vaccine cuts the risk of hospital admission by roughly 30 to 40 per cent in older adults. That protection rate is lower than for some other vaccines, but it is in line with flu vaccine performance in past years. For that reason, advice has not changed. Vaccination remains the single most effective step people can take to protect themselves and to ease pressure on the NHS.

Why Does The Vaccine Have Different Effectiveness In Different Age Groups?

This season’s vaccines are still doing a solid job of preventing severe illness. Vaccinated children are about 70 to 75 per cent less likely to need a hospital visit or admission for flu. Among adults, the reduction is closer to 30 to 40 per cent.

One reason for this gap is the type of vaccine used. Children receive a nasal spray, while adults are given an injection. Research shows the nasal spray works particularly well in children but is less effective in adults, which is why different recommendations exist. So the comparison reflects not just age, but also different vaccines.

Another factor is prior immunity. Adults have encountered many flu viruses over their lifetime, so the added benefit of each new vaccine dose may be smaller than it is for a child. Even so, that extra protection still matters and can make a real difference.

A medical expert has revealed that you might be able to tell which winter illness you’re dealing with just by the type of cough you have. According to Dr. Rupa Parmar, a GP and medical director at Midland Health, coughing can present differently depending on whether you have a cold, flu, or COVID-19. During the winter months, certain infections become more common. Viruses spread more easily in cold weather, and spending more time indoors with others makes transmission more likely.

Still, it can be tricky to identify exactly what’s wrong because symptoms often overlap. Dr. Parmar advises: “There are some key differences between a cold, Covid, and flu that make it easier to tell them apart. But if you’re unsure, always check with your doctor. It’s better to be safe when it comes to your health.”

Cold and Flu

Dr. Parmar explained: “A cold usually causes a mild cough, while a flu cough is typically dry.” According to the NHS, cold symptoms develop gradually over two to three days. In contrast, flu symptoms “come on very quickly,” with a dry cough being a key sign.

Covid

Covid can also cause a dry cough, but it is usually persistent. Dr. Parmar said: “Covid tends to trigger a dry, continuous cough. Many people cough for over an hour at a time or have three or more coughing episodes in a single day.”

The NHS defines this as: “A new, continuous cough—meaning you’re coughing a lot for more than an hour or have three or more coughing episodes within 24 hours.”

What Is ‘Super Flu’?

NHS officials are warning that the UK may be facing an unusually severe flu season. Cases have started a month earlier than usual, driven by a stronger strain of the influenza A(H3N2) virus, sometimes being called “super flu.” Despite its intensity, vaccines remain effective against this strain, offering protection to those who get immunized.

Other Key Covid Symptoms

Other signs of Covid to watch for include:

• High temperature—you may feel hot, cold, shivery, or notice heat on your chest or back (you don’t always need a thermometer)
• Loss or change of smell or taste
• Shortness of breath
• Feeling very tired or drained
• Body aches
• Headache
• Sore throat
• Stuffy or runny nose
• Loss of apetite
• Diarrhea
• Nausea or vomiting

The NHS warns: “Covid symptoms can resemble those of other illnesses like colds or flu. Most people recover within a few weeks, but some may take longer. If you have a cough, pharmacists can offer guidance on treatment.”

If You Have Covid

The NHS advises staying at home and avoiding contact with others if you or your child:

• Have a high temperature
• Do not feel well enough to attend work, school, childcare, or daily activities
• You can resume normal activities once you feel better or no longer have a high temperature.