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

Squirrels could be natural hosts of the mpox virus (MPXV) -- that causes monkeypox disease -- according to a recent study by German researchers.

The team from the Helmholtz Institute for One Health (HIOH) identified the fire-footed rope squirrel (Funisciurus pyrropus) as a likely natural reservoir of the MPXV.

The study published in the journal Nature revealed that sooty mangabeys – a primate found in West Africa -- can contract mpox by eating infected squirrels. The disease may present mild lesions, but it can also cause more severe skin lesions or even be fatal.

"Identifying the animal sources of the virus and the exposure routes that lead to inter-species transmission are key steps towards understanding spillover mechanisms and developing effective prevention measures to mitigate the risk of transmission to humans," said Livia V. Patrono, one of the senior authors at HIOH.

Squirrels Suspected MPXV Hosts

While squirrels have long been suspected as potential reservoirs for MPXV, their role was confirmed after an investigation of an mpox outbreak among wild sooty mangabeys (Cercocebus atys) in Côte d'Ivoire.

During the outbreak, reported in early 2023, nearly one-third of the primates showed clinical signs of disease, and four infants died.

The team conducted viral genome sequencing and found that the infected monkeys carried a virus that was nearly identical to an MPXV strain identified in a fire-footed rope squirrel found dead 12 weeks earlier nearby.

Further, the team analyzed fecal samples from the mangabeys. A sample collected eight weeks before the outbreak's onset contained DNA from both the virus and the rope squirrel. This provided strong evidence of interspecies transmission at that moment.

Sooty mangabeys have been previously observed catching and eating fire-footed rope squirrels, which provide a direct route for the transmission of viruses.

Mpox Continues To Spread Globally

Although mpox is no longer a public health emergency, outbreaks of clade I and clade II strains of the mpox virus are continuing in many countries around the world, especially in Africa.

Last week, Madagascar announced the country's first death from mpox, a 3-year-old girl from the island nation’s eastern city of Toamasina.

The WHO has also confirmed that two cases of the recombinant strain – combining genomic elements of clades Ib and IIb of the monkeypox virus (MPXV) – have been identified to date: one in the United Kingdom and one in India.

Mpox is an infectious disease caused by the monkeypox virus (MPXV), part of the Orthopoxvirus genus, which also includes the virus that causes smallpox.

It spreads through close physical contact, including sexual contact, and in some cases through contaminated materials or respiratory droplets.

Symptoms typically include fever, swollen lymph nodes, rash, and/or lesions.

The global health body has also urged all countries to “remain alert to the possibility of MPXV genetic recombination.” It has also urged for continued epidemiological surveillance, sequencing, vaccination of at-risk groups, and infection prevention and control measures.

An international group of scientists has created an artificial intelligence tool that can estimate a woman’s likelihood of developing breast cancer within the next four years.

The AI tool, known as the BRAIx risk score, analyzes mammogram images to generate an individualized risk assessment and flag women who may face a higher chance of developing the disease.

It may not only show the current risk but also predict the future risk, enabling early detection and treatments for a better outcome.

According to the findings published in The Lancet Digital Health journal, nearly one in 10 women ranked in the top 2 percent of risk by the AI tool were diagnosed with breast cancer within four years. This was despite previously receiving a clear screening result.

“These risk scores enable future development of personalized screening pathways to transform population breast cancer screening and save lives,” said corresponding author Helen M. L. Frazer of the University of Melbourne.

Frazer noted that identifying women who appear cancer-free but carry very high risk -- comparable to those with inherited BRCA1 or BRCA2 mutations -- will unravel both hereditary and non-hereditary causes of breast cancer.

From one-size-fits-all screening to personalization

Breast cancer screening programs have significantly lowered mortality rates -- by roughly 40-50 percent among women aged 50 to 74. However, most screening systems still apply the same approach to all women, regardless of individual risk.

Traditional screening tools use genetics, breast density, and questionnaires to estimate breast cancer risk. On the other hand, new AI-based screening tools, such as BRAIx personalizes screening by gathering information already present in breast scan images to better identify who is at higher risk.

“Our results show that conventional mammographic density is a far weaker predictor of breast cancer risk than the BRAIx risk score, even for interval cancers,” the researchers said in the paper. Interval cancers are aggressive tumors diagnosed after a negative mammogram.

The BRAIx Tool

The BRAIx risk score was developed using mammograms from nearly 400,000 women. To prove its efficacy, the AI tool was tested on data from almost 96,000 women from Australia and then confirmed in an independent Swedish population of over 4,500 women.

The findings showed that:

• The BRAIx risk score estimated breast cancer risk more accurately than the traditional risk factors, such as breast density, country of birth, and even family history.

• For the top 2 percent of women with the highest BRAIx risk score, the probability of a cancer diagnosis within 4 years was 9.7 percent -- a risk level exceeding that typically seen in women with inherited BRCA1 or BRCA2 mutations.

The BRAIx risk score can:

• Make breast screening more personalised,
• Improve early cancer detection,
• Reduce false alarms,
• Save lives without increasing costs

Global Breast Cancer Burden

Breast cancer continues to be the most common cancer among women worldwide.

A recent study published in The Lancet Oncology journal predicted that the number of new cases of the deadly disease will reach more than 3.5 million globally in 2050 -- rising by a third from 2.3 million in 2023.

Annual deaths from the disease will also rise by 44 percent -- from around 764,000 to 1.4 million.

However, not smoking, getting sufficient physical activity, lowering red meat consumption, and having a healthy weight can help prevent over a quarter of healthy years lost to illness and premature death from breast cancer.

People who survived a COVID-19 infection can be at significant risk for kidney disease, acute kidney injury, and chronic kidney disease. compared to individuals who were not infected, according to a study.

The study, published online in the journal Communications Medicine, revealed that COVID patients have

• a 2.3-times higher risk of acute kidney injury
• a 1.4-times higher risk of chronic kidney disease
• a 4.7 times higher risk of kidney failure

“While we’re in the post-pandemic era, this shows that COVID-19 history is an important variable when considering the long-term impact of the infection on kidney function and disease,” said first author Yue Zhang, who was at Pennsylvania State University, US, while conducting the study. Zhang is currently a postdoctoral scholar at Johns Hopkins Bloomberg School of Public Health.

How Was The Study Conducted?

For the study, data on over 3 million working-age adults in the United States were analyzed.

The team compared the effect of influenza, another common viral infection that affects kidney health, and people with a history of COVID infection on kidney infections.

Using a machine learning model, the individuals were followed between 180 and 540 days for the emergence of new acute or sudden kidney disease.

The results showed that:

• Both COVID and the flu can worsen kidney health
• Flu caused a mild and temporary effect
• COVID increased the risk of acute kidney injury for a longer duration
• COVID survivors developed kidney disease within a few hours to a few days
• COVID patients had a longer-term chronic and end-stage kidney disease.

How COVID Worsens Kidneys Health

The Penn State researchers explained that kidney cells express high levels of the primary protein receptors that SARS-CoV-2 uses to enter and infect cells. Kidney cells also produce specialized enzymes that help viruses enter cells.

According to Kidney Health Australia, an acute COVID infection can impact the kidneys with fevers and respiratory symptoms, and/or worsening blood sugar control.

The US National Institutes of Health stated that renal dysfunction is an increasing clinical indicator of COVID propagation.

Citing several studies, the NIH said that the most common clinical manifestation is proteinuria -- found in more than half of the COVID patients. In addition, hematuria, elevated blood urea nitrogen, and elevated serum creatinine are other common features in Covid survivors with poor kidney health.

Nasr Ghahramani, Professor of Medicine at Penn State College of Medicine, stressed the need for COVID survivors, especially those with diabetes and high blood pressure, to take "more frequent and more prolonged monitoring of their kidney function" to enable early detection and better outcomes.