“In health and in sickness, pure water is one of Heaven’s choicest blessings. Its proper use promotes health. It is the beverage which God provided to quench the thirst of animals and man. Drunk freely, it helps to supply the necessities of the system, and assists nature to resist disease.” –Counsels on Diet and Foods, p. 419
Poets refer to water as the elixir of life. Scientists refer to water as a nutrient. Water is second only to oxygen as essential to life. We can live perhaps six weeks without food, six days without water, and three minutes without air. Water is by far the most abundant substance on earth and in our bodies.
Although 70% of the planet’s surface is water, most of it is salt water in the oceans. Only 3% of the world’s freshwater is safe for drinking, and 97% of that is frozen in glaciers in areas like Antarctica. That leaves us with less than 1% usable water from lakes, rivers and underground sources. Almost 900 million people do not have access to safe drinking water—about one in every eight people. The World Health Organization (WHO) says that every year more than 3.4 million people die as a result of water related diseases, making it the leading cause of disease and death around the world. 90% of the deaths that occur from unsafe water are in children under five years old, who die of illnesses caused by organisms that live in water sources contaminated by raw sewage. In fact, diseases from unsafe water and lack of basic sanitation kill more people every year than all forms of violence, including war. Clean water is essential to human health. “Thousands have died for want of pure water and pure air, who might have lived.” –Healthful Living, p. 155
FUNCTION OF WATER IN THE BODY
The single largest nutrient in our body is water. Up to 60% of the human adult body is water. The brain and heart are composed of 73% water, the lungs are about 83% water, skin is 64% water, muscles and kidneys 79%, and bones 31%. Because of this, proper hydration is vital for the proper functioning of the human body.
Water performs numerous, distinct and vital body functions. It transports oxygen and essential nutrients to cells, and also transports hormones, enzymes, platelets, and blood cells to the part of the body where they are needed. It removes wastes from cells. Water also facilitates excretion of waste products and toxins, mostly in urine. Water provides lubrication for joints, for the digestive tract, and for the organs. It is contained in saliva and other secretions that lubricate food as it passes through the digestive tract. Water keeps the skin moist, which helps to prevent infections. Water also assists in cells maintaining their shape, as it is an integral part of cell membranes. It helps to cushion organs and maintains body structures, such as bones. It works as a shock absorber for the brain and spinal cord, and for the fetus during pregnancy. Water helps in regulating body temperature by either absorbing heat or releasing heat through perspiration. All metabolic processes (what keeps us alive) occur in a water medium.
WATER BALANCE—HYDRATION
Body water balance refers to the net results of balance between water intake and water loss. When the net difference is equal, water balance is maintained. Our bodies are constantly losing water, as vapour in our breath, and in liquid from perspiration and urine, and via our feces, which must be replaced to stay hydrated. This is referred to as the “obligatory water loss”. A loss of just 1–2% of body water can put a strain on the heart, and cause both health and performance to suffer.
In most healthy adults, thirst is used as a guide that fluids need to be increased either from beverages or food, to balance out a loss of water. The body also concentrates urine to reduce water loss. As a consequence, a negative fluid balance is usually short-lived. If unusual circumstances don’t impact the major routes of water loss, water balance is maintained. To identify whether or not you have adequate hydration, observe the colour of your urine. It should be the colour of pale straw. If it is darker, you are either becoming dehydrated or are already dehydrated. Also, if your feces are hard and dry, and difficult to pass, this can also be as a result of dehydration. These both should be signals for you to drink more fluids.
Although it is well known that water is essential for survival, only recently have we begun to understand its role in the maintenance of brain function. Current findings suggest that particular cognitive abilities (thinking, learning, memory) and moods are influenced by water consumption. Maintaining proper fluid levels will improve cognition and mood. The negative impact of dehydration on cognition and mood has most relevance for those with poor fluid balance, such as the elderly and children.
The amount of fluid to maintain proper hydration varies depending on age, body size, physical activity level, health status, food intake patterns and environmental conditions, such as humidity and temperature. Therefore, recommendations for total water intake, including beverages and foods, should take into consideration regional and international differences, in addition to lifecycle and special health needs. For example, in the United States and Canada, the Institute of Medicine (IOM) based their recommendation for water intake on data showing that about 75–80% of total water intake comes from drinking water and other beverages, with the remaining 20–25% coming from foods. For physically active people 19 years and older, that translates to an average daily fluid intake of 3 liters (about 13 cups) for males and 2.2 liters (about 9 cups) for females. On average, a sedentary adult should drink 1.5 liters of water per day. Water is the only liquid nutrient that is really essential for body hydration.
DEHYDRATION
Dehydration is defined as the loss of water and salts essential for normal body function. Dehydration occurs when the body loses more fluid than it takes in. Once someone is dehydrated, they are also suffering electrolyte imbalances (loss of salt, potassium), as electrolytes are also eliminated from the body when water is lost. Dehydration can occur in anyone of any age, but it is most dangerous for babies, small children, and older adults.
Dehydration can occur in many different circumstances. These include: illness; a hot, dry climate, with little rain; prolonged exposure to the sun or extreme temperatures; not drinking enough water; excessive urination; nausea; overuse of medications or substances such as alcohol or coffee that increase urination; diabetes; kidney disease; adrenal gland problems. Dehydration upsets the fluid-salt balance that is needed to maintain healthy cells and tissues.
Age is a factor that can contribute to dehydration. Healthy young and middle-aged adults who drink when they are thirsty generally do not need to do anything more to maintain their body’s fluid balance. Children need more water because they are more energetic, but they tend to drink when thirsty. Because of their small size, children can get dehydrated easily if they are ill, and if they then experience either vomiting or diarrhea. They also may not take in enough fluids to compensate for extra losses of fluid associated with a fever or sweating. An infant can become dehydrated within hours after becoming ill; a sign of dehydration is no urination in an eight-hour period. Dehydration is a major cause of infant death throughout the world.
Adults over the age of 60 often do not drink adequate amounts of water. If they only drink when they are thirsty, they are only getting about 90% of the fluid that they need, which increases the risk of dehydration. The ability to sense thirst is diminished when adults age. Therefore, older adults need to drink a certain amount of fluids per day, whether they feel thirsty or not.
Mild dehydration is when the body has lost no more than 5% of its water. Loss of 5–10% is considered moderate dehydration. Severe dehydration with a loss of 10-15% of the body’s water is a life-threatening condition that requires immediate medical attention. Severe dehydration can require hospitalization and intravenous fluid replacement. If an individual’s blood pressure drops enough to cause or threaten the development of shock, medical treatment is usually required.
Symptoms of dehydration at any age include cracked lips, dry or sticky mouth, lethargy, and sunken eyes. The skin is less elastic than it should be and is slow to return to its normal position after being pinched. Dehydration can cause confusion, constipation, discomfort, drowsiness, fever, and thirst. The mucous membranes lining the mouth and nose lose their natural moisture. When the body’s fluid supply is severely depleted, hypovolemic shock is likely to occur. This condition, which is also called physical collapse, is characterized by pale, cool, clammy skin; rapid heartbeat; and rapid, shallow breathing. At this point, blood pressure drops so low that the organs of the body are not getting enough fluid to continue functioning. The internal temperature of the body rises to temperatures that can cause permanent damage to the brain and also to other vital organs.
Climate conditions: The hotter it is, the more you perspire and the more you need to drink. However, even in the winter, high rates of energy used in winter activities such as snowboarding, ice skating, and skiing while wearing heavy clothing can also cause significant fluid loss through sweat, resulting in the need to increase fluids.
Higher Elevations: Have you ever noticed how hard and frequently you breathe when you hike or exercise at a higher elevation? With every breath you exhale, you are losing fluid. High altitudes also tend to have low humidity, which increases fluid losses through the skin. People tend to drink less at high altitudes likely due to a decreased sensation of thirst. If you are staying at a higher elevation, and especially if you are exercising at high elevations, remember to drink plenty of fluids.
Air travel: The air inside airplanes during flight tends to have very low humidity—only about 15%. Low humidity increases dehydrating water losses through the skin, which in turn increases your need to drink. On a long flights, it is important to drink plenty of fluids.
While I was visiting the Grand Canyon, I heard a story about a woman who was hiking down into the canyon. She became confused and very weak. She died of dehydration within a few feet from the water of the Colorado River. Her companions were not aware of the signs of dehydration, nor did they realize how dangerous a situation she was in before it was too late. In general, physical activity affects water balance much more than climate or altitude, but the combination increases water loss at a faster rate.
It is important to understand hydration needs in every situation you are in, and always maintain proper hydration. Choosing beverages that fit your activity level and lifestyle is key to proper hydration while staying within the body’s energy needs.
OVERHYDRATION
The importance of consuming adequate fluids to avoid dehydration is extremely important for physically active people. However, overhydration can occur during long periods of exercise (for example recreational hiking, and marathon running) because electrolytes that are also lost through sweat are not replaced, yet excessive amounts of water are consumed. The importance of fluid consumption has, in some cases, overshadowed the risk of consuming too much plain water, without replacing the lost electrolytes which leads to dangerous electrolyte imbalances, such as hyponatremia, a serious condition in which the sodium (salt) level in the blood becomes too low. Large amounts of water are consumed without adequate salt (sodium) intake. Both water and salt must be replaced to prevent dehydration and electrolyte imbalances. Therefore, during prolonged heat or exercise, which results in excess perspiration, not only should water be replaced, but so should the electrolytes, including sodium and potassium.
The World Health Organization (WHO) also notes that this condition occurs in mountain climbers who use melted snow to prepare their beverages, without supplementing with the necessary electrolytes.
Once dehydrated, older adults who engage in prolonged exercise can experience decreased thirst sensitivity, which can make them slower to voluntarily rehydrate. Older adults also tend to have slower kidney responses to water and sodium levels in the body and may be at greater risk for hyponatremia.
The symptoms of hyponatremia tend to be neurological (brain). People may complain of headache, nausea and vomiting, lethargy, and confusion. Other symptoms include cramps, muscle twitching and weakness. Ironically, the symptoms mimic dehydration, but if only water is given, this worsens the condition of hyponatremia. If the sodium concentration drops quickly to critical levels; lung congestion, brain swelling, seizures, coma, and death may occur.
TREATMENT OF DEHYDRATION/OVERHYDRATION
Increased fluid intake and replacement of lost electrolytes (sodium, potassium) are usually enough to restore fluid balances in those who are mildly or moderately dehydrated. Beverages that contain high levels of potassium include coconut water and fruit juices. However, coconut water is low in sodium, and does not contain enough sodium to replace the amount typically lost in dehydration. If using coconut water, add salt tablets to your drink. Processed 100% fruit juices, such as orange juice contain potassium as well as added sodium, which make them good for replacing lost electrolytes. However, they are also high in sugar. Vegetable juices, especially tomato juice, are high in sodium, with less sugar content. Salt can also be added to your water. Another option is to eat a snack that contains salt, along with drinking plain water, to reverse dehydration.
For people who are losing fluid through vomiting or diarrhea, drink enough fluids for urine to remain the colour of pale straw to ensure adequate hydration.
Infants and young children who lose fluids through vomiting or diarrhea can be given electrolyte solutions, such as unflavoured Pedialyte. The unflavoured version does not contain any artificial additives. In developing countries, the WHO (World Health Organization) provides Oral Rehydration Salts (ORS), a solution of glucose and sodium, to combat dehydration from childhood diarrhea. Fruit juices should be avoided in hydrating infants and young children under the age of five, as the high sugar content will worsen diarrhea.
Medical treatment should be initiated when the following occurs:
- a child less than three months old develops a fever higher than 100 °F (37.8 °C)
- a child more than three months old develops a fever higher than 102 °F (38.9 °C)
- symptoms of dehydration worsen
- an individual urinates very sparingly or does not urinate at all during a six-hour period
- dizziness, listlessness, or excessive thirst occur
Mild dehydration rarely results in complications. If the cause is eliminated and lost fluid is replaced, mild dehydration can usually be cured in 24-48 hours.
Vomiting and diarrhea that continue for several days without adequate fluid replacement can be fatal. The risk of life-threatening complications is greater for young children and the elderly. However, dehydration that is rapidly recognized and treated has a good outcome.
HOW TO MAINTAIN GOOD HYDRATION
- Have beverages in between meals, after the food has left your stomach. Drink several glasses of water before going outside on a hot day.
- Choose beverages that you enjoy. Include soup with your meals.
- Eat more fruits and vegetables. Fruits and vegetables tend to have a high water content, which makes them great options for helping you meet your hydration needs. They also contain electrolytes.
- Do not exclusively rely on thirst. Sometimes thirst is not a reliable measure of hydration because of exercise, medications, age or health conditions. Keep a water bottle or beverage at your desk, in your car, in your bag or where ever you will be reminded to drink.
- Keep beverages at a moderate temperature. Fluids served at moderate temperatures—temperatures that are neither hot nor cold—tend to be consumed in greater volumes.
Increase fluid intake when exercising. If your typical exercise session is around 60 minutes or less, and does not involve vigorous activity outdoors in hot, humid weather, you probably do not need to interrupt your exercise session for a drink. However, when exercising in hot weather and you are losing water and salt from sweating, ensure that you drink at least one cup of fluid every 20 minutes, and include salt and potassium either in your drink or in a snack.
To get the greatest benefit from water, it must be consumed between meals; one hour before or two hours after a meal is ideal. “Many make a mistake in drinking cold water with their meals. Food should not be washed down. Taken with meals, water diminishes the flow of saliva; and the colder the water, the greater the injury to the stomach. Ice water or ice lemonade, taken with meals, will arrest digestion until the system has imparted sufficient warmth to the stomach to enable it to take up its work again. Masticate slowly, and allow the saliva to mingle with the food.
“The more liquid there is taken into the stomach with the meals, the more difficult it is for the food to digest; for the liquid must first be absorbed.” –Counsels on Diet and Foods, p. 106
In 2006, experts at the American Conference on Hydration and Health Promotion discussed guidelines for adequate hydration. They noted that “water is essential for life and health, yet hydration and fluid intake have not received adequate attention in public guidelines.” They agreed that science links adequate hydration to survival, health promotion, sustained physical and mental performance, and workplace safety and productivity.
“Water is the best liquid possible to cleanse the tissues.” –Healthful Living, p. 226