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

The effects of heatwaves, air pollution, noise and overall climate change may extend beyond physical health. According to a new report by the Earth–Brain–Health Commission published in Nature Mental Health recently, they can have a significant impact on mood, cognitive function and overall psychological wellbeing.

The commission warns that environmental changes are altering the conditions in which people live. It also talks about consequences for brain health and mental wellbeing. It also calls for mental health to become a consideration in climate policy, urban planning and environmental decision making, rather than being treated only after symptoms develop.

The findings are relevant to low and middle-income countries, where exposure to environmental hazards can overlap with greater socioeconomic problems like poverty and limited access to healthcare.

“Heat and heatwaves, air and noise pollution, extreme weather and compound events, urbanization, and the loss of green and blue spaces are associated with depression, anxiety, cognitive decline, and impaired emotional and behavioral functioning,” the commission states.

Effects Of Environmental Conditions On Brain

Also read: Lancet Study Finds Air Pollution & Chemical Exposures Could Add To South Asia's Diabetes & Heart Disease Burden

From biological changes like neuroinflammation, disruption of hormones and the body's internal clock to psychological stress and due to isolation and displacement, the commission identifies several ways through which environmental conditions may impact mental health.

Heat exposure is one of the gravest concerns in current times. Heatwaves can disrupt sleep and contribute to physiological stress, while air pollution can lead to cognitive decline. Noise pollution and stressful urban environments may fuel anxiety and depression.

These exposures are compounded by people’s standard of living. A person living in poorly ventilated housing, for example, may face heat, air pollution, financial hardship and limited access to healthcare at the same time. These combined problems can be difficult to measure by studying each exposure separately.

Who Is At Risk?

Also read: Rising AQI In Delhi-NCR: Doctors Warn Of Lung And Heart Risks As Pollution Builds

Children, older adults, people with disabilities and marginalised communities may face greater exposure to environmental hazards while having fewer resources and help to cope with them.

The commission also highlights low and middle-income countries and small island developing states. These populations may face significant environmental risks but remain underrepresented in research on climate change and mental health.

Dr Vivek Benegal, senior professor of psychiatry and former head of department at the National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, is among the commission's members. He said NIMHANS has been examining how climate change affects the human brain.

Benegal also pointed to a 2023 study conducted by researchers from NIMHANS and King's College London. The study found that even low levels of arsenic exposure, below World Health Organization thresholds, were associated with changes in brain structure and impaired cognitive abilities among children, adolescents and young adults.

Commission's Recommendations

The report recommends that governments should incorporate brain and mental health measures into environmental policies. Its recommendations include monitoring environmental exposures, identifying risks early in life, and designing healthier urban environments.

“The principal obstacles to action are organisational and financial rather than evidential,” the commission observes, noting that research cohorts, Earth-observation systems and environmental governance tools already exist but are often maintained separately.

COVID-19 vaccines were rolled out during the pandemic, so questions about their safety, how long they protect against infection and whether mRNA technology was tested for long enough continue to dominate public debate.

Dr Paul Offit, paediatrician and director of the Vaccine Education Center at Children’s Hospital of Philadelphia and former member of the CDC’s Advisory Committee on Immunization Practices, says many concerns overlook the the evidence collected before and after the vaccines were introduced.

In an interview with HealthandMe, Offit discussed how long COVID vaccine protection lasts, what scientists have learnt about rare side effects and why the technology behind mRNA vaccines was not as new as many people thought.

“I think it is probably the best studied vaccine in human history,” Offit said. He pointed to the large number of people who received them and the safety-monitoring systems used to look for adverse effects.

Why Are People Still Getting COVID After Vaccination?

Also read: EXCLUSIVE: Ex-CDC Vaccine Advisor Says Measles Outbreak Bigger Than Reported, Slams RFK Jr’s ‘No-See Evil’ Approach

The circulation of SARS-CoV-2, the virus that causes COVID-19, is sometimes used to argue that the vaccines do not work. Offit said this misunderstands the type of infection the virus causes and the protection vaccination offers.

“It’s a short incubation period mucosal infection,” he said. “So, vaccination or natural infection will protect you for about four to six months from mild to moderate disease, should protect you for longer against severe disease.”

He compared the future of COVID to influenza, saying that infections will continue even as vaccines help protect against serious illness.

“Even if everybody in the world were vaccinated every year, that virus would still circulate,” he said. “This virus is now with us forever.”

Offit said the goal of COVID vaccination is not necessarily to prevent every infection. It is to reduce the risk of hospitalisation and death, particularly among people most likely to develop severe disease.

“The goal of the vaccine is to keep you out of the hospital and to keep you from dying,” he said.

He said that people over 75, those with chronic heart or lung disease, pregnant women and people with weakened immune systems are at higher risk of developing severe complications from COVID. He said these groups should receive a vaccine every year.

Dr Paul Offit On COVID Vaccine’s Side Effects

Also read: American COVID Drives Cases And Deaths In UK: Unusual XFG Symptoms To Watch For

When COVID vaccines were first authorised in December 2020, the clinical trials involved approximately 35,000 participants across the Pfizer-BioNTech and Moderna studies, Offit said. Some rare side effects of the vaccine became apparent only after the vaccines were administered to much larger populations.

One such side effect was myocarditis, an inflammation of the heart muscle, and, less commonly, pericarditis, which affects the lining around the heart.

“Very quickly, it was found to be a rare cause, roughly 1 in 50,000 myocarditis,” Offit said, referring to mRNA COVID vaccines. He said cases were seen primarily in males aged 16 to 29 and were generally short-lived.

Current evidence confirms that myocarditis and pericarditis are rare but recognised risks associated with mRNA COVID vaccines. The risk has been observed most often in adolescent and young adult males, particularly within seven days after a second dose.

In June 2025, the US Food and Drug Administration required updated safety warnings for the Pfizer-BioNTech and Moderna vaccines. The FDA also noted that some patients in follow-up studies continued to show signs of heart muscle injury on MRI scans, with improvement in some cases. The long-term significance of these findings remains under investigation.

Offit also cited the example of Johnson & Johnson COVID vaccine, which was associated with a rare but serious condition involving blood clots and low platelet counts. The vaccine was no longer available in the US by May 2023.

“You're always looking and trying to find any rare side effect that's associated with the vaccine,” he said.

He added that concerns about stillbirths and pregnancy outcomes had circulated despite research examining vaccination during pregnancy.

Offit said there was “no evidence of congenital malformations, no evidence of premature birth or spontaneous abortion” in the studies he was referring to.

How Long Were mRNA COVID Vaccines Tested?

Another common concern is that mRNA COVID vaccines were developed too quickly and that the technology had not been studied for long enough. Offit disagreed, saying that the technology was not entirely new.

“I think it was studied for a long time,” he said. He pointed to research into mRNA as a vaccine platform that began decades before the COVID-19 pandemic.

“Drew Weissman and Katie Carrico met in 1997 and started working on mRNA as a vaccine platform, for which they won the 2023 Nobel Prize in Medicine,” Offit said.

He also referred to efforts to develop mRNA vaccines against SARS, the coronavirus that caused an outbreak in 2002 and 2003.

“But we really had, really since 1997, information about this vaccine, so like more than 20 years of studies of that vaccine,” he said. “People think it was a new vaccine, but it really wasn't that new.”

The technology had been studied before COVID-19, although the pandemic vaccines themselves still required clinical trials to establish their safety and effectiveness. After their introduction, researchers continued monitoring them to identify rare adverse events.

Do Benefits Of COVID Vaccines Still Outweigh The Risks?

Offit said the decision to vaccinate should take into account both the risk of side effects and the risk posed by COVID itself. “I'm an older person, so I'm going to get a COVID vaccine every year because I think that the benefits clearly outweigh the risks,” he said.

He argued that COVID continues to cause hospitalisations and deaths, making protection against severe disease an important consideration.

He said that the benefits outweigh the risks, particularly for people at higher risk of serious illness. Individual decisions should also take account of age, underlying health conditions, previous vaccination and current medical guidance.

One of the most common contributing factors in lung cancer is smoking but a recent report suggests an alarming pattern in which cases among non-smokers are on the rise.

Pope Leo XIV was recently diagnosed with lung adenocarcinoma, a type of aggressive cancer that develops in the cells lining the lungs. He had no history of smoking. The 71-year-old pontiff underwent surgery to have part of his right lung lobe removed. According to reports, he is out of the hospital and recovering well.

Another case is of Stanford physician Bryant Lin whose stubborn cough led him to seek medical attention. After six weeks, he underwent an X-ray. The diagnosis stated that he had stage 4 lung cancer. Lin was less than a month away from turning 50, and he had never smoked a cigarette in his entire life.

“Definitely a shock,” Lin recalled according to The Washington Post. By the time doctors identified the cancer in spring 2024, it had spread to his liver, bones and brain.

According to the US Centers for Disease Control and Prevention (CDC), around 10% to 20% of lung cancers in the United States are reported in people who have never smoked or have smoked fewer than 100 cigarettes in their lifetime. That amounts to an estimated 20,000 to 40,000 cases annually.

For these patients, their no-smoking history can delay diagnosis and treatment. Hence, researchers are now looking into how environmental exposures, genetic causes and the biology of tumours may contribute to lung cancer in non-smokers.

Lung Cancer In People Who Have Never Smoked

Also read: Pope Leo XIV, Diagnosed With Lung Cancer, Undergoes Surgery As His Brother Battles Relapsed Multiple Myeloma

Smoking remains the leading risk factor for lung cancer. But other reasons like exposure to radon, secondhand smoke, air pollution and asbestos can also increase risk. Family history plays a role, especially when a first-degree relative has cancer before age 50.

Researchers are also examining genetic differences that may help explain why some people develop lung cancer despite never smoking.

A study published in September identified a rare genetic mutation concentrated in the southeastern United States that was associated with a 60-fold higher risk of lung cancer among non-smokers. The finding focuses on a possible role for inherited susceptibility, but it does not explain most cases in this group.

Lung cancer also has a different demographic profile among people who have never smoked. Women who have never smoked are more than twice as likely as their male counterparts to develop lung cancer.

“Two-thirds of nonsmoking-related lung cancer happens in women, so there’s certainly an association with female sex,” said Jaclyn LoPiccolo, a medical oncologist at Dana-Farber Cancer Institute who co-authored the mutation study.

She added, “Nonsmoking-related lung cancer is also more common in people of East Asian descent, but whether that’s a genetic or environmental association, we don’t yet know.”

These Cancers Are Often Diagnosed Late

Also read: Pope Leo XIV Resumes Daily Activities After Lung Cancer Surgery: How Recovery Looks Like After Lung Lobe Removal

People who have never smoked may not recognise a persistent cough or other respiratory symptoms as signs of lung cancer. Doctors may initially consider more common explanations if the patient has no smoking history.

Never-smokers are often diagnosed late at more advanced stages of the disease because their doctors initially consider lung cancer to be less likely.

Haiying Cheng, a medical oncologist at Montefiore Einstein Medical Center in New York, said the stigma surrounding the disease can compound the problem. “A cancer diagnosis should never become a judgment about a patient,” Cheng said.

She added that clinicians need to consider assumptions beyond smoking when it comes to lung cancer and focus on the patient’s risk profile and tumour biology.

Lin is receiving antibody therapy targeting a cancer-driving mutation. He had a positive response to treatment.

“The treatment has done wonders for me,” he said. “When I was a medical student or resident, I would have never thought a Stage 4 lung cancer patient could be very productive and have a high quality of life almost two-and-a-half years after diagnosis.”

In the United States, the US Preventive Services Task Force recommends annual low-dose CT screening for adults aged 50 to 80 who have a smoking history. People who have never smoked are not included in these recommendations.

As researchers dig deeper into lung cancer chances in non-smokers, there is growing interest in different screening recommendations. Taiwan, for example, has a national early-detection programme offering low-dose CT scans to non-smokers with a family history of lung cancer.

Lin has urged his own sons to consider screening at a younger age. “I’ve got two sons, and I told them, ‘When you hit 45 or even 40, think about getting screened,’” he said.