What to know about endometriosis


Endometriosis is an incurable but manageable gynecological condition.

It occurs when endometrial implants, comprised of tissue normally found within the uterus, are present in other areas of the body.

As the tissue continues to thicken, break down, respond to menstrual cycle hormones, and bleed during the menstrual cycle, endometriosis forms deep inside the body.

Scar tissue and adhesions form, and this can cause organ fusion and anatomical changes.

Endometriosis is thought to affect around 11 percent of women in the United States aged between 15 and 44 years.

Fast facts on endometriosis

Here are some key points about endometriosis. More information is in the main article.

  • Endometriosis affects between 6 and 10 percent of women of reproductive age worldwide.
  • The condition appears to be present in a developing fetus, but estrogen levels during puberty are thought to trigger the symptoms.
  • Symptoms are generally present during the reproductive years.
  • Most women go undiagnosed, and in the U.S. it can take around 10 years to receive a diagnosis.
  • Allergies, asthma, chemical sensitivities, autoimmune diseases, chronic fatigue syndrome, fibromyalgia, breast cancer, and ovarian cancer are linked to women and families with endometriosis.

What is endometriosis?

Endometrial tissue consists of gland, blood cells, and connective tissue. It normally grows in the uterus, to prepare the lining of the womb for ovulation.

Endometrial implants are buildups of endometrial tissue that grow in locations outside the uterus.

When they grow outside the uterus, this is called endometriosis.

They can develop anywhere in the body, but they usually occur in the pelvic area.

They may affect:

  • the ovaries
  • the fallopian tubes
  • the peritoneum
  • the lymph nodes

Normally, this tissue is expelled during menstruation, but displaced tissue cannot do this.

This leads to physical symptoms, such as pain. As the lesions grow larger, they can affect bodily functions. For example, the fallopian tubes may be blocked.

The pain and other symptoms can affect different areas of life, including the ability to work, medical care costs, and difficulty maintaining relationships.

Symptoms

Other medical conditions such as pelvic inflammatory disease (PID), ovarian cysts, and irritable bowel syndrome (IBS) can mimic the symptoms of endometriosis.

Symptoms of endometriosis include:

  • Severe menstrual cramps, unrelieved with NSAIDS
  • Long-term lower-back and pelvic pain
  • Periods lasting longer than 7 days
  • Heavy menstrual bleeding where the pad or tampon needs changing every 1 to 2 hours
  • Bowel and urinary problems including pain, diarrhea, constipation, and bloating
  • Bloody stool or urine
  • Nausea and vomiting
  • Fatigue
  • Pain during intercourse
  • Spotting or bleeding between periods

Pain is the most common indication of endometriosis, but the severity of the pain does not always correlate with the extent of the disease.

Pain often resolves following menopause, when the body stops producing estrogen production. However, if hormone therapy is used during menopause, symptoms may persist.

Pregnancy may provide temporary relief from symptoms.

Complications

Complications include:

  • infertility, which can affect 50 percent of those with the condition.
  • increased risk of developing ovarian cancer or endometriosis-associated adenocarcinoma
  • ovarian cysts
  • inflammation
  • scar tissue and adhesion development
  • intestinal and bladder complications

It is important to see a health care provider about symptoms, to avoid future complications.

Treatment

Surgery is possible, but it is normally considered only if other treatments are not effective.

Other options include:

Pain medications: Either over-the-counter (OTC) nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin IB, others) or prescription drugs for the treatment of painful menses.

Hormones: Treatment may be with hormonal therapies such as hormonal birth control, Gonadotropin-releasing hormone (Gn-RH) agonists and antagonists, Medroxyprogesterone (Depo-Provera) or Danazol. Placement of an intrauterine device (IUD) may also be recommended.

Surgery: Initial surgery will seek to remove the areas of endometriosis, but a hysterectomy with removal of both ovaries may be necessary.

Fertility treatment: Pregnancy may be recommended via in-vitro fertilization (IVF).

Managing symptoms at home

Complementary and alternative treatments may include acupuncture, chiropractic, and herbal medicine, but there is little evidence to show that these are effective.

Avoiding caffeine may help to reduce pain, as caffeine can worsen symptoms.

Exercise, such as walking, may reduce pain and slow the progress of the condition by reducing estrogen levels.

It is important to monitor symptoms, because of the long-term complications of endometriosis. Intolerable pain or unexpected bleeding should be reported to a doctor.

Although there is currently no cure for endometriosis, most women are able to relieve the pain of symptoms and will still be able to have children.

Diagnosis

Diagnosis can be challenging because there is no single test for evaluation.

The only way to truly confirm the condition is by undergoing a surgical laparoscopy.

A surgical laparoscopy is a minimally invasive procedure in which a thin, lighted tube with a miniature camera attached, called a laparoscope, is inserted through a small incision in the pelvic area.

A diagnosis can be categorized as follows:

  • Stage 1: Lesions are minimal and isolated
  • Stage 2: Lesions are mild. There may be several and adhesions are possible.
  • Stage 3: Lesions are moderate, deep or superficial with clear adhesions
  • Stage 4: Lesions are multiple and severe, both superficial and deep, with prominent adhesions.

It can take many years to receive a diagnosis.

Other possible diagnostic strategies include a pelvic exam, radiologic imaging with ultrasound or magnetic resonance imaging (MRI), and the use of certain medications including birth control or gonadotropin releasing hormone (GnRH) agonists.

Diet

Dietary steps have been suggested for managing the pain and effects of endometriosis.

A 2004 study suggests that a brown seaweed called bladderwrack may have an estrogen-reducing effect in women. This can reduce the growth rate of endometriosis.

One author presented a case study using a diet low in short-chain-fermentable carbohydrates to reduce the symptoms of endometriosis. This diet has been shown to work on IBS and since it is often found with endometriosis, then perhaps the diet would be effective for those with only endometriosis.

More research is needed, but there is little harm in trying this approach.

Dietary choices have also been linked to the development of endometriosis. A study carried out in 2011 suggested that fruit intake increased the risk of endometriosis and a higher total fat intake decreased the risk.

Dairy products were also shown to reduce the risk of endometriosis, although these results were not statistically significant.

Eating yogurt, sauerkraut, and pickles or finding a good source of probiotics may help reduce gastrointestinal symptoms and cause increased digestive activity.

Avoiding caffeine may help to reduce pain, as caffeine can worsen symptoms.


All about dementia, Medical Myths 

Today, an estimated 5.8 million people aged 65 years or older in the United States have dementia. Due to the fact that the average lifespan of people in the U.S. has increased over recent decades, some experts project that by 2050, the number of older adults with dementia could reach 13.8 million.

1. Dementia is inevitable with age

This statement is not true. Dementia is not a normal part of aging.

According to a report that the Alzheimer’s Association published, Alzheimer’s disease, which is the most common form of dementia, affects 3% of people aged 65–74 years in the U.S. As a result of the risk increasing as we age, 17% of people aged 75–84 years and 32% of people aged 85 years and older have a dementia diagnosis.

2. Dementia and Alzheimer’s disease are the same thing

This is not quite correct. Alzheimer’s is a type of dementia, accounting for 60–80% of all dementia cases. Other types of dementia include frontotemporal dementia (FTD), vascular dementia, mixed dementia, and Lewy body dementia.

The National Institute on Aging define dementia as “the loss of cognitive functioning — thinking, remembering, and reasoning — and behavioral abilities to such an extent that it interferes with a person’s daily life and activities.”

Although dementias share certain characteristics, each type has a distinct underlying pathology.

Alzheimer’s disease is associated with a buildup of so-called plaques and tangles in the brain. These structures interfere with brain cells, eventually killing them. In contrast, brain cell death in vascular dementia occurs due to a lack of oxygen, which can result from a stroke, for instance.

FTD, as another example, occurs when abnormal protein structures form in the frontal and temporal lobes of the brain, causing the brain cells in these regions to die.

3. A family member has dementia, so I will get it

A common myth is that dementia is purely genetic. In other words, if a person’s family member has a dementia diagnosis, they are guaranteed to develop dementia later in life. This is not true.

Although there is a genetic component to some forms of dementia, the majority of cases do not have a strong genetic link.

As we learned above, rather than genetic factors, the most significant risk factor for dementia is age. However, if a parent or grandparent developed Alzheimer’s when they were younger than 65 years, the chance of it passing on genetically is higher.

Early-onset Alzheimer’s is relatively uncommon, though. It occurs in about 5.5% of all Alzheimer’s cases.

As the majority of dementia cases are Alzheimer’s disease, this means that most dementia cases are not hereditary. FTD, which is much less common, has a stronger genetic link, but if a parent or grandparent develops the condition, it does not mean that children or grandchildren are guaranteed to develop it.

Today, FTD affects an estimated 15–22 in every 100,000 people. Of these individuals, 10–15% have a strong family history of the condition.

4. Dementia only affects older adults

Age is a risk factor for dementia, but dementia can affect younger adults in rare cases. Some scientists estimate that, in people aged 30–64 years, 38–260 people in 100,000 — equivalent to 0.038–0.26% — develop early-onset dementia.

In the 55–64 age bracket, this increases to close to 420 people in 100,000, or 0.4%.

5. Using aluminum pans causes Alzheimer’s

In the 1960s, scientists injected rabbits with high levels of aluminum. They found that the animals developed neurological lesions similar to those that form in the brains of people with Alzheimer’s.

Additionally, some studies have identified aluminum within the plaques associated with Alzheimer’s. However, aluminum also appears in the healthy brain, and researchers have not established a causal link between this element and the disease.

Following on from these studies, myths still circulate that drinking from aluminum cans or cooking with aluminum pots increases the risk of Alzheimer’s.

However, since those early experiments, scientists have not found a clear association between Alzheimer’s and using aluminum pots and pans.

Although researchers will, eventually, establish the precise relationship between aluminum and Alzheimer’s, consuming aluminum through the diet is unlikely to play a major role.

As the Alzheimer’s Society explain: “Aluminum in food and drink is in a form that is not easily absorbed into the body. Hence, the amount taken up is less than 1% of the amount present in food and drink. Most of the aluminum taken into the body is cleaned out by the kidneys.”

However, they also write that some research has found “a potential role for high dose aluminum in drinking water in progressing Alzheimer’s disease for people who already have the disease.”

6. Dementia signals the end of a meaningful life

Thankfully, this is not the case. Many people with a dementia diagnosis lead active, meaningful lives. Some people fear that if a doctor diagnoses them with dementia, they will no longer be able to go for a walk alone and will have to stop driving their vehicle immediately.

It is true that these adjustments may come in time as the condition progresses, but in mild cases of dementia, no changes may be necessary. As dementia worsens, changes to the way an individual leads their life are likely, but that does not mean that the person cannot lead a fulfilling life.

“Too many people are in the dark about dementia — many feel that a dementia diagnosis means someone is immediately incapable of living a normal life, while myths and misunderstandings continue to contribute to the stigma and isolation that many people will feel,” explains Jeremy Hughes, former Chief Executive of the Alzheimer’s Society.

7. Memory loss always signifies dementia

Although memory loss can be an early symptom of dementia, it does not necessarily signify the start of this condition. Human memory can be unpredictable, and we all forget things occasionally. However, if memory loss is interfering with everyday life, it is best to speak with a doctor.

Although memory issues tend to be an early sign of Alzheimer’s disease, that is not the case for other forms of dementia. For instance, early signs and symptoms of FTD can include changes in mood and personality, language difficulties, and obsessive behavior.

8. Dementia is always preventable

This, unfortunately, is untrue. Importantly, though, certain factors can either reduce the risk of certain types of dementia developing or delay their onset.

For instance, the Lancet Commission’s 2020 report on dementia prevention, intervention, and care lists 12 factors that increase the risk of dementia:

  • less education
  • hypertension
  • hearing impairment
  • smoking
  • obesity
  • depression
  • physical inactivity
  • diabetes
  • low levels of social contact
  • alcohol consumption
  • traumatic brain injury
  • air pollution

Some of these factors are more difficult to modify than others, but working on changing any of them might help reduce the risk of developing dementia. The authors of the report explain:

9. Vitamins and supplements can prevent dementia

Linked to the section above, this is also false. To date, there is no strong evidence that any vitamin or mineral supplements can reduce the risk of dementia. In 2018, the Cochrane Library conducted a review with the aim of answering this question.

Their analysis included data from more than 83,000 participants across the 28 included studies. Although the authors report “some general limitations of the evidence,” they conclude:

10. All people with dementia become aggressive

In some cases, people with dementia might find it increasingly hard to make sense of the world around them. This confusion can be frustrating, and some individuals might respond to the emotions in an angry manner. However, this is not the case for everyone.

In a study involving 215 people with dementia, 41% of the participants developed aggression during the 2-year study. When they looked at factors that increased the risk of developing aggression, the researchers identified two of the primary factors as physical pain and a low quality relationship between the person and their caregiver.

11. Dementia is never fatal

Unfortunately, dementia can be fatal. According to a recent study, which appears in JAMA Neurology, dementia may be a more common cause of death than experts have traditionally thought it to be. The authors “found that approximately 13.6% of deaths were attributable to dementia over the period 2000–2009.”

Dementia worries people, especially as they age, and this is justifiable in many ways. However, it is important to counter misinformation that might enhance concerns and stigma.

For now, researchers are working tirelessly to develop better ways to treat and prevent dementia. In the future, hopefully, science will reduce the impact of dementia and, therefore, the fear associated with the condition.

Water: Do we really need 8 glasses a day?


We often hear that we should drink eight 8-ounce glasses of water a day. However, there is some controversy about this figure and what it really means.

Water is an essential nutrient. It is necessary to sustain all forms of life, and humans can only live a few days without it. It is also a healthful drink.

Health authorities and others often encourage people to consume 2 or more liters of water a day, but is this only plain water or does water from other sources count?

Some sources have described these recommendations as a “myth,” and professionals have questioned the guidelines.

Some point to a lack of scientific evidence to support the claims, while others note that promoters of the concept have included a major mineral water producer.

How much plain water do we really need?

Fast facts on water intake

Here are some key points about daily water consumption.

  • Foods and fluids, including water, are the main source of water in our bodies.
  • The advice to drink eight 8-ounce glasses of water a day is not based on evidence.
  • The amount of water we need depends on individual needs and circumstances, including activity and climate.
  • The healthy body naturally maintains a well-tuned balance of fluid, and the thirst mechanism tells us when we need more.

Recommended daily water intake

In 1945, the U.S. Food and Nutrition Board advised people to consume 2.5 liters (84.5 fluid ounces (fl oz) of water a day, including fluid from prepared foods.

Today, the Centers for Disease Control and Prevention (CDC) say, “There is no recommendation for how much plain water adults and youth should drink daily.” However, there are recommendations about total fluid intake from all sources.

In 2004, the Institute of Medicine set the amount at around 2.7 liters, or 91 fluid ounces (fl oz) of total water a day for women and an average of around 3.7 liters (125 fl oz) daily for men.

This refers to the total daily fluid intake from all sources, defined as “the amount of water consumed from foods, plain drinking water, and other beverages.”

The U.S. Dietary Guidelines 2015-2020 do not recommend a specific daily water or fluid intake, but they do recommend choosing plain rather than flavored water and juices with added sugar.

There is currently no set upper level for water intake, although excessive quantities have been known to have adverse effects.

In the United Kingdom, the National Health Service (NHS) recommend consuming 6 to 8 glasses a day, or 1.9 liters (almost 34 fl0.oz), including water that is in food. They note this amount is suitable for a temperate climate. In hotter climates, they say, more will be needed.

Recommended intake by age

There is no fixed amount of fluid recommended by age, but some patterns emerge among healthy individuals doing a moderate amount of activity in a temperate climate.

The following shows average water intake for infants and adults:

Age group Average daily fluid intake
Infants From 525 ml for a 3.5-kilo newborn to 1,200 ml for an 8-kilo infant per day, as breast or bottled milk
Adults aged 19 to 30 years Average of 3.7 liters a day for men and 2.7 liters for women, depending on climate, activity, pregnancy status, and health

Infants

The amount of formula or breast milk an infant takes in averages 780 milliliters (ml), or just over 26 fl oz, of breast milk or formula milk each day until the age of around 6 months. Before the age of 6 months, plain water is not recommended.

This ranges from around 525 ml (just under 18 fl oz) a day for 3.5-kilo newborn to 1,200 ml per day (45 fl oz) for an 8-kilo infant at 6 months, or around 150 ml (5 fl oz) per kilo of weight per day.

This is proportionally far more than an adult needs. After infants start consuming solid foods, they need less fluid from breast milk and formula.

Children aged over 12 months

Children should be encouraged to drink water:

  • as part of the daily routine, for example, after brushing teeth and before, during and after playtime at school
  • when the weather is warm
  • as an alternative to sweetened drinks and juices

Juice consumption should be limited to one glass a day.

Parents are advised to keep a pitcher handy to encourage healthful water-drinking habits, and schools should have water fountains or equivalent facilities.

Children who are sick with a fever

For children who are at risk of dehyration, for example, with a fever, the CDC recommend the following:

Age Amount of fluid needed
Up to 12 months 3 cups
1 to 3 years 4 cups
4 to 8 years 5 cups
6 to 13 years 8 cups
14 years and over 11 to 13 cups for males and 8 to 9 cups for females

If a child is sick with a fever, it is important to seek medical help. A doctor may also advise oral an rehydration solution to ensure an adequate electrolyte balance.

Adults aged 19 to 30 years

The CDC cites figures showing that in 2005-2010 in the U.S., young people were drinking an average of 0.45 liters or 15 fl oz of water on a given day, while adults drank an average of 1.2 liters, or 39 fl oz.

The adequate intakes recommended for total water from all sources each day for most adults between 19 and 30 years of age are:

  • 3.7 liters (or about 130 fl oz) for men
  • 2.7 liters (about 95 fl oz) for women

One source suggests a man’s requirements might range from 2.5 liters (84.5 fl oz) if sedentary to up to 6 liters (203 fl oz) if active and living in a warm climate.

For women, the requirements will probably be 0.5 to 1 liter (17 to 34 fl oz) lower than those for men because of typically smaller body mass.

However, during pregnancy, women are likely to need an extra 0.3 liters (10 fl oz), and an additional 0.7 to 1.1 liters (23 to 37 fl oz) while breast-feeding.

Older adults

Older adults may be at risk of both dehydration and overhydration, as a result of health conditions, medications, loss of muscle mass, reduction in kidney function, and other factors.

Older adults who are well hydrated have been found to have:

  • fewer falls
  • less constipation
  • in men, a lower risk of bladder cancer

Dehydration has been linked to a higher frequency of:

  • urinary tract infections
  • confusion
  • kidney failure
  • slower wound healing

Needs for fluid intake will depend on the individual.

Few studies have looked at fluid input and output in older people, but at least one has concluded that it is not significantly different from that of younger people.

Those caring for older people are encouraged to provide fluids regularly and assist with ambulation, especially if a reduction in mobility makes it harder to visit the bathroom.

Where do the figures come from?

While water is known to be crucial for life and for preventing dehydration, recommendations for intake are based mainly on survey results showing the average amounts that people consume.

Conclusions are based on the assumption that these amounts must be about right for optimal hydration.

There is little evidence showing that specific quantities have a particular effect on health.

It is impossible to define an optimal intake, because these vary greatly according to:

  • activity
  • environmental conditions
  • individual factors
  • body mass
  • sex and age
  • health status, for example, poor kidney function
  • medications, such as diuretics
  • whether or not a person is pregnant or breast-feeding

Recommendations that a person should drink eight glasses of water a day also fail to take into account the fact that much of our fluid intake comes from food and other drinks.

Sources of water

Water in the body comes not only from drinking water.

Estimations vary, but according to one source:

  • around 20 to 30 percent comes from food
  • some 60 to 70 percent comes from drinking water and other fluids
  • a small percentage, about 10 percent is “metabolic water,” produced by cells during normal cell function

The more active the body is, the more metabolic water is produced.

Some surveys suggest that around 20 percent of water intake comes from foodstuffs and the rest is from fluids. This depends on diet. A higher intake of fresh fruit and vegetables will mean a higher intake of water from foods.

Metabolic water accounts for around 250 to 350 ml (8.4 to 11.8 fl oz) a day.

Water content of foods

Here are some examples of the water content of different foods and fluids:

Water content as a percentage (%) Food or drink
100% Water
90-99% Fat-free milk, tea, coffee, juicy fruits such as strawberries and cantaloupes, vegetables such as lettuce, celery, and spinach
80-89% Fruit juice, yogurt, fruits such as apples, pears and oranges, vegetables such as carrots, and cooked broccoli
70-79% Bananas, avocados, baked potatoes, cottage and ricotta cheeses
60-69% Pasta, beans, and peas, fish such as salmon, chicken breasts, and ice cream
30-39% Bread, bagels, and cheddar cheese
1-9% Nuts, chocolate cookies, crackers, cereals
0% Oils and sugars

Tap or bottled water?

Bottled or tap water are equally effective at hydrating the body. In terms of hydration, studies in the UK have not found any significant difference between drinking the two.

Mineral waters contain different amounts of minerals, depending on where they come from, but this, too is not significant, as most minerals come from other dietary sources.

What about coffee?

Caffeinated drinks are thought to be dehydrating as opposed to hydrating because of a belief that they have a diuretic effect on our water balance.

A number of studies to test how caffeinated fluids affect hydration have shown that tea and coffee are in fact good sources of water and do not lead to dehydration.

One study of 18 healthy male adults found that no significant difference in impact on hydration, measured in body weight, urine and blood tests after a variety of caffeinated, non-caffeinated, caloric, and non-caloric drinks.

“Advising people to disregard caffeinated beverages as part of the daily fluid intake is not substantiated,” say the researchers.

Another concludes that there is “no evidence of dehydration with moderate daily coffee intake.”

Benefits of drinking water

Water is necessary for the body. It:

  • regulates temperature
  • lubricates the joints and bones
  • protects the spinal cord and other sensitive tissues
  • removes waste from the body

Short-term benefits

A healthy fluid intake, including water, prevents dehydration.

The short-term symptoms of significant dehydration include:

  • unclear thinking
  • mood change
  • overheating
  • feeling thirsty and having a dry mouth
  • fatigue
  • dizziness
  • headache
  • dry mouth, eyes, and lips
  • urinating less than usual

Overheating can lead to organ damage, coma, and death.

The CDC urge people to make sure they drink enough water before, during, and after physical work, especially if this involves activity in a hot climate. This can help maintain alertness and effectiveness.

In a hot environment, you may need one 8-ounce cup every 15-20 minutes, but not more than 48 ounces in one hour, as this can lead to hyponatremia, a low level of sodium.

Plain water provides hydration without adding calories or jeopardizing dental health. Sports drinks can be useful in moderation, but too many will add unnecessary sugar to the body.

Long-term benefits

Studies suggest that long-term benefits of drinking water might include a lower risk of:

  • colorectal cancer and cancers of the urinary system
  • heart disease
  • urinary tract infections
  • kidney stones
  • constipation
  • high blood pressure
  • stroke

However, these possible long-term benefits also depend on a wide variety of other factors.

In addition, study participants with the lower risk of these conditions still drank fewer than eight 8-ounce glasses of water a day.

Weight loss

Drinking water may also help with weight loss, if a person “preloads” with water before a meal. This may help them feel fuller faster during meals. If they choose water over sweetened juice or soda, they consume fewer calories.

In a study where 318 people with obesity or overweight switched from sugary drinks to plain water, an average loss of 2 to 2.5 percent in weight was noted. But this could be easily explained by a decrease in total calories rather than water itself.

Other possible benefits

Other supposed benefits of drinking more water include prevention of:

  • migraine
  • nosebleeds
  • depression
  • high blood pressure
  • asthma
  • dry cough
  • dry skin
  • acne

However, there is little or no scientific evidence to confirm these claims.

In children, a higher water consumption has been linked to better diets, behavior and overall health.

When is more water needed?

Extra water may be needed when a person:

  • is in a hot climate
  • is doing physical activity
  • has diarrhea or vomiting
  • has a fever

These can lead to additional loss of water.

What about a water detox?

There have also been claims that water can “detox” the body.

These claims are not based on scientific facts.

The liver, kidneys, and human body normally break down toxic substances into less harmful ones or expel them from the body through urine. Water does not have a unique role in these processes.

Too much water can lead to hyponatremia, also known as low sodium. Low sodium levels can be life-threatening causing confusion, seizures, coma and death.

Hydration during exercise

During exercise, factors affecting the amount of fluid lost and the need for extra intake include:

  • the type and intensity of the activity
  • environmental factors, such as climate
  • the size and muscle mass of the athlete

Guidance from the American College of Sports Medicine (ACSM), published in 2007, recommends making an individual estimation of the fluid replacement needed by people taking part in exercise, to avoid dehydration.

Larger athletes may require higher fluid intake, for example, compared with smaller, leaner athletes, due to a larger body surface and higher body weight.

The ACSM advises drinking water during activity to prevent:

  • dehydration that leads to a fall in body weight of more than 2 percent
  • changes in the electrolyte balance

These changes, they say, can lead to reduced performance.

However, a study published in the British Journal of Sports Medicine concludes that a loss of up to 3 percent of water has “no effect” on real-world sports performance.

The conclusions were supported by findings from a cycling time-trial over 25 kilometers in hot conditions of 91.4° Fahrenheit and 40 percent relative humidity.

Results showed no difference in performance, physiological, and perceptual variables between participants who received hydration and those who did not.

The reason for this, say the authors, is “the body’s rapid defense of its plasma and blood volume following dehydration.”

In other words, the body can regulate water balance with high sensitivity.

Authors of a study focusing on runners in the 2002 Boston Marathon, published in the New England Journal of Medicine (NEJM), concluded:

“Because runners vary considerably in size and in rates of perspiration, general recommendations regarding specific volumes of fluids and frequencies of intake are probably unsafe and have been superseded by recommendations favoring thirst or individual perspiration rates as a primary guide.”

A review of 15 studies found that exercise-induced dehydration did not reduce performance. The authors encouraged athletes to “drink according to their thirst.”

Water and dehydration in the human body

Dehydration can be measured in terms of blood and urine osmolality.

Osmolality is an estimation of the osmolar concentration of plasma. It reflects the concentration of particles in a solution.

As regards dehydration:

  • high osmolality indicates a greater need for hydration
  • low osmolality suggests there are too few particles, specifically sodium and electrolytes, a sign of overhydration

How much water is in the human body?

The main chemical making up the human body is water. It accounts for between 55 percent and 75 percent of the body’s composition, and it varies between individuals.

  • in the average young man, between 50 and 70 percent of the body weight is water
  • in infants, 75 percent of body weight is water
  • in older people, it is 55 percent

Differences of age, sex, and aerobic fitness affect an individual’s ratio of lean to fat body mass and therefore how much water they contain.

Calculating human water needs

The amount of water we need to take in to maintain a healthy balance is decided by how much water we use and lose that must be replaced.

Over the course of 24 hours, healthy resting adults regulate their water balance to within around 0.2 percent of body weight.

In older children and adults, if a person’s body weight falls by 3 percent due to fluid loss, this is considered dehydration. Moderate dehydration is when weight falls by 6 percent, and severe dehydration is when it falls by 9 percent.

It is difficult to measure the amount of water used or lost by the body. Measures taken across groups of people in studies have shown wide variation.

However, if people show symptoms of dehydration, such as confusion or decreased urine output, they need medical attention.

What about dark urine?

There is a popular concept that darker urine means a person is dehydrated, while pale urine shows they are adequately hydrated.

However, it is difficult to assess the significance of urine color precisely. It depends on the time of day, medications, and other health problems.

Tea- or cola-colored urine, particularly after exercise, can indicate serious muscle injury and severe dehydration and requires urgent medical attention.

However, in normal circumstances, urine that is well within the limits of normal osmolality in laboratory tests can appear moderately yellow. This does not indicate that a person is dehydrated.

In addition, other factors such as diet, medications and health conditions can cause individuals to differ in their urine color.

How does the body regulate water?

Without water, there is no life. For this reason, all living organisms have adapted to avoid dehydration.

Humans can only survive for a few days without water. Infants and older people who lose water through illness and do not replace it can experience life-threatening complications.

Most of the time, however, our bodies’ sensitive natural mechanisms maintain appropriate fluid levels, or homeostasis, as long as we continue to consume food and water.

The two main ways the body does this are:

Thirst: This which tells us when we need to take in more fluid.

Urine output: The kidneys regulate any excess or lack of the water we consume by either emptying it into the urinary bladder or holding onto it in the blood plasma.

The body expels 0.5 to 1 liter (around 17 to 34 fl oz) per day in the form of urine.

The kidneys also:

  • regulate the balance of electrolytes, such as sodium and potassium, in the body fluids
  • receive hormonal signals to conserve or release water into the urine if the brain detects changes in the concentration of the solutes in the blood

The brain also responds to these changes in solutes, known as plasma osmolality. This is one factor that triggers the thirst for water.

Other ways in which water is lost or expelled from the body are:

Breathing: About 250-350 ml (8.5 to 11.8 fl oz) per day exit from the lungs during. exhalation

Feces: Around 100-200 ml (3.4 to 6.8 fl oz) per day passes out of the body in feces.

Sweating: Sedentary loss ranges from around 1,300-3,450 ml (44 to 117 fl oz) a day, but a physically active person can lose 1,550-6,730 ml (52 to 227.5 fl oz) a day

What about ‘8 by 8’?

It is often said that we needed to drink at least eight glasses of water a day, although there is little scientific evidence to support this.

Prof. Heinz Valtin, of Dartmouth Medical School in Hanover, NH, is one expert who has questioned this advice. He suggests it may be not only unnecessary but maybe even harmful.

In an article published in the American Journal of Physiology in 2002, he concludes:

“Not only is there no scientific evidence that we need to drink that much, but the [8 by 8] recommendation could be harmful, both in precipitating potentially dangerous hyponatremia and exposure to pollutants, and also in making many people feel guilty for not drinking enough.”

Prof. Heinz Valtin

The right types of fluid

Recommendations are now more likely to note that water can come from other beverages and from food. However, these should be chosen carefully.

Beverages that are high in fat or sugar or contain alcohol do not benefit health, and plain water is recommended in preference to these.

More than one alcoholic beverage per day in women and more than two alcoholic beverages per day in men on a regular basis can lead to liver inflammation and injury, an increased cancer risk, as well as negatively affecting every system of the body.

Fatty or sweetened drinks increase calories and lack nutritional value.

Processed foods, such as burgers and chips, high fat, and high sugar diets will contain less water than fresh fruits and vegetables.

Nearly all foods contain water, but fresh and healthful ingredients contain the most compared to processed foods, sugars, and fats.

The CDC note with concern that young people who consume high quantities of junk food are also drinking less water and eating less fresh fruit and vegetables. This can lead to further health problems. They are also often drinking highly sweetened beverages rather than water.

A study published by the CDC in 2013 showed that:

  • Seven percent of adults said they did not drink any water
  • Thirty-six percent said they drank 1 to 3 cups a day
  • Thirty-five percent reported drinking 4 to 7 cups
  • Twenty-two percent said they drank 8 cups or more

Those who drank the least water were also less likely to pursue other healthful behaviors, such as consuming fresh fruits and vegetables.

Too much water?

Some have raised concerns that consuming too much water could be dangerous.

Not only the amount of fluid in the body but the balance of minerals that is important for maintaining health and life.

Too much water in the body could lead to hyponatremia, or water intoxication, when sodium levels in the blood plasma become too low.

Symptoms include:

  • lung congestion
  • brain swelling
  • headache
  • fatigue and lethargy
  • confusion
  • vomiting
  • seizures
  • coma
  • death

Hyponatremia may be a risk for people who use the recreational drug Ecstasy. This is likely due to a variety of reasons including a change in hormone levels, brain chemistry, body function, kidney function, along with increased sweating and thirst.

People who drink too much water while exercising could also be at risk. In the Boston runners survey, for example, almost 2,000 of the participants were thought likely to have some degree of hyponatremia due to excessive fluid consumption, and 90 may have finished with critical hyponatremia.

Another risk factor is having certain diseases or using some medications. Diabetes, for example, can lead to excessive thirst. Conditions in which the kidneys cannot excrete enough water, too, can result in this type of problem.

However, just as the body can adapt to higher or lower levels of water and can remind us, through thirst, when we need to drink more, scientists believe an internal mechanism also stops most people from drinking too much water.

Takeaway

There are few scientific measures of how much water we need.

Most studies have focused on how much people consume and assumed that this figure matches or exceeds our needs. It does not determine whether a person is efficiently hydrated or not.

The amount of water a person uses and loses varies according to conditions and activities. Heat, activity, and illness, such as diarrhea and vomiting, can lead to dehydration.

Most healthy people in a temperate climate consume sufficient fluid to remain healthy while carrying out their daily activities, and around one fifth to a quarter of this comes from food. Where there is a lack, the body will usually regulate these needs.

Meanwhile, those who work outside or exercise in a hot climate will not be able to get all their water needs from food. They will need additional water.

Perhaps, as Prof. Farrell of Monash University says, “If we just do what our body tells us, we will probably get it right.”

Q:

Should people aim to consume a particular quantity of water each day?

A:

The most recent research supports the theory that thirst is the best guide for determining fluid intake. For the average individual, even in routine physical activity, allow thirst to determine when and how much you drink. 

Those with certain medical conditions, such as kidney disease or heart failure, may need to follow their doctor’s advice regarding daily fluid intake in order to avoid the complications of low sodium levels in their blood.

Judith Marcin, MD

Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.


Immune aging and how to combat it


With age, the human immune system becomes less effective at tackling infections and less responsive to vaccinations. At the same time, the aging immune system is associated with chronic inflammation, which increases the risk of almost all conditions linked to old age.

The good news is that exercising and adopting the right diet may help a person maintain healthy immunity into older age.

Chimpanzees and gorillas, our closest primate relatives, live for only 10–15 years in the wild once they have reached maturity. After the human evolutionary lineage split from theirs, our ancestors’ life expectancy doubled over the next 5 million years.

Scientists believe that it remained relatively stable into the 18th century. In the 250 years between then and now, however, life expectancy more than doubled again due to improvements in sanitation and healthcare.

We live in a time of high average life expectancies. However, our long evolutionary history has adapted us for different lifestyles (and even life expectancies), and these have changed drastically.

As a result, immunity not only weakens in older age; it also becomes imbalanced. This affects the two branches of the immune system — “innate” immunity and “adaptive” immunity — in a double whammy of “immunosenescence.”

“Innate” immunity, which is our first line of defense against infections, fails to resolve after the initial threat has passed, causing chronic, systemic inflammation.

“Adaptive” immunity, which is responsible for remembering and attacking particular pathogens, steadily loses its ability to defend against viruses, bacteria, and fungi.

Chronic, low-grade inflammation is associated with almost all conditions linked to older age, including type 2 diabetes, cardiovascular disease, cancer, and dementia. It also plays a leading role in certain autoimmune conditions that are more common in older adults, such as rheumatoid arthritis.

Meanwhile, the loss of adaptive immunity that comes with older age not only makes people more susceptible to infections; it can also reactivate dormant pathogens that were previously suppressed.

In addition, the weaker adaptive immunity of older adults means that their bodies respond less strongly to vaccinations, such as the annual flu shot.

Aging and innate immunity

Researchers have dubbed the persistent, low-level inflammation that is implicated in almost all conditions associated with older age as “inflammaging.”

“While inflammation is part of the normal repair response for healing, and essential in keeping us safe from bacterial and viral infections and noxious environmental agents, not all inflammation is good. When inflammation becomes prolonged and persists, it can become damaging and destructive.”

After an initial infection or injury, younger people’s immune systems switch to an anti-inflammatory response. This does not appear to happen as effectively in older adults. This is due to the accumulation of aged, or “senescent,” immune cells.

Senescent cells have shorter telomeres, which are the protective caps at the tips of chromosomes. Just as the plastic caps on the ends of shoelaces prevent them from fraying, telomeres prevent vital genetic material from becoming lost when the chromosome is copied during cell replication.

Telomeres get a little shorter every time a cell divides, until, eventually, division has to stop completely. If the cell survives, it becomes steadily more dysfunctional.

Senescent immune cells produce more immune signaling molecules called cytokines, which promote inflammation. Specifically, they churn out more interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha).

Scientists have linked high levels of IL-6 and TNF-alpha to disability and mortality in older adults. They have a particularly strong association with type 2 diabetes, cardiovascular disease, neurodegenerative disease, and cancer.

As the number of pro-inflammatory cells increases, there is an increase in the number of immune cells called M1 macrophages (more pro-inflammatory) and a decrease in the number of M2 macrophages (more immunoregulatory).

These changes in the frequency of M1 and M2 cells seem to be associated with an increased risk of developing plaques comprising fat and debris, which block the arteries in atherosclerosis.

Aging and adaptive immunity

Through adaptive immunity, the immune system learns to recognize and neutralize particular pathogens.

A type of immune cell known as a T cell plays a crucial role in adaptive immunity. In the course of an infection, “naïve” T cells learn to recognize the specific pathogen involved. They then differentiate into cells that are specialized to mount future immune responses against the same pathogen.

The total number of T cells remains constant throughout our lifetime, but the pool of naïve, undifferentiated cells steadily shrinks over the years, as more and more cells commit to tackling specific infections.

As a result, the bodies of older adults become less able to mount effective immune responses to new infections. For the same reason, vaccinations provoke weaker responses from the aging immune system and, therefore, provide less protection.

Ironically, a lifetime of influenza vaccinations may, in itself, diminish the efficacy of the annual vaccine later in life. Indeed, research suggests that repeated influenza immunizations could lead to reduced antibody responses.

Many older adults harbor a latent infection of human cytomegalovirus. This viral infection is very common and persistent, and it usually produces few (if any) symptoms. However, in older adults, this infection may steadily deplete their immune resources, making them more prone to other viral infections and reducing the effect of influenza immunizations.

In addition to this slow decline in immunity with age, senescent T cells also produce more pro-inflammatory cytokines, such as IL-6. These, in turn, stoke the chronic, systemic inflammation of inflammaging.

Holding back the years

Although nothing can prevent aging, there are certain lifestyle changes a person can make to stay healthy into older age.

The sections below will look at these factors in more detail.

Getting regular physical activity

Exercise has a profound effect on the immune system, according to a recent overview of research in the journal Nature Reviews Immunology.

Inevitably, people become less physically active as they age, but there is evidence to suggest that getting as much exercise as possible can slow or even reverse some of the effects of immunosenescence.

Skeletal muscle produces a range of proteins called myokines that reduce inflammation and preserve immune function. Therefore, it makes sense that maintaining muscle mass through exercise protects against infection and conditions such as type 2 diabetes and cardiovascular disease, which are closely linked to chronic inflammation.

One study found that aerobic fitness among 102 healthy males, aged 18–61 years, was inversely proportional to the number of senescent T cells in their blood after adjusting for age. In other words, increased physical fitness was associated with less immunosenescence.

The fittest males not only had fewer senescent T cells but a greater number of naïve T cells.

Another study compared the immune responses of 61 healthy males, aged 65–85 years, to a flu vaccination. Around one-third of the males were intensively active (though participation in running or sports), one-third were moderately active, and one-third were mostly inactive.

After adjusting for their age, the researchers found that the intensively and moderately active males produced more antibodies in response to vaccination than the least active males.

Remarkably, the more active males had higher serum concentrations of antibodies to some flu strains even before they underwent vaccination.

A range of other studies have identified similar benefits, not only from long-term physical activity but also from single bouts of exercise before vaccination.

“Taken together, these studies suggest that the emergence of certain features of immunosenescence and the extent of immune remodeling is likely to be heavily influenced by insufficient physical activity as humans age.”

It is important to note that the majority of the research into the relationship between exercise and immunity in older adults has involved “cross-sectional” studies. This type of study investigates relationships between variables at a single point in time.

To confirm the benefits of physical fitness, the authors of the review above call for more “interventional” studies, which would follow participants over time.

Adopting the Mediterranean diet

For now, there is no direct evidence to suggest that making dietary changes can slow the rate of immunosenescence in older adults. However, there is plenty of indirect evidence.

In particular, research suggests that diet helps determine older adults’ risk of developing sarcopenia. This condition causes a loss of muscle mass, strength, and functionality.

There appears to be a two-way relationship between skeletal muscle and the immune system. Muscles produce anti-inflammatory myokines, but recent evidence suggests that chronic inflammation also accelerates the muscle loss in sarcopenia.

Taking dietary supplements that reduce the risk of sarcopenia — such as vitamin D and polyunsaturated fatty acids — may help, due to their anti-inflammatory properties.

A growing body of evidence also suggests that people who eat a Mediterranean diet are less likely to become “frail” in older age, such as by losing muscle strength, walking slowly, and tiring easily.

The Mediterranean diet comprises:

  • large amounts of fruit, leafy vegetables, and olive oil
  • moderate amounts of fish, poultry, and dairy
  • low amounts of red meat and added sugar

Previous studies have linked this diet to a lower risk of obesity, cardiovascular disease, type 2 diabetes, and cancer.

A 2018 review of observational studies, which Medical News reported on, found that people who adhered the most closely to the Mediterranean diet were less than half as likely to become frail over a 4-year period, compared with those who followed it the least closely.

Among other possible explanations, this may be a result of the diet’s anti-inflammatory properties. The authors write:

“Frail individuals have higher levels of inflammatory markers, and inflammation is considered to be closely associated with frailty. A Mediterranean diet is associated with low levels of inflammatory markers and may reduce frailty risk through this mechanism.”

Maintaining a moderate weight

Although muscle plays a role in reducing inflammation in older adults, fat, or “adipose,” tissue may have the opposite effect.

Normal aging often leads to weight gain, due to an accumulation of adipose tissue beneath the skin and around the organs. According to a roundup of research on the aging immune system, adipose tissue may make a significant contribution to inflammaging.

Up to 30% of the pro-inflammatory cytokine IL-6 in the bloodstream may originate from adipose tissue. Therefore, having obesity or overweight in older age may significantly contribute to chronic inflammation.

In addition, animal and human studies suggest that the immune system of people with obesity may produce fewer antibodies in response to the flu vaccination.

Exercising and eating a healthful diet appear to counter the effects of immune aging. In part, this might be due to the way that these two lifestyle factors prevent excessive weight gain.

Studies have suggested that older adults who exercise regularly and have a moderate weight have fewer senescent T cells and lower levels of pro-inflammatory cytokines in their blood.

However, whether or not diet, exercise, and weight loss can reverse immunosenescence remains an open question for future research.