Dehydration

The human body is made up of over 60% water weight. All of the tissues in the body contain water and muscle is about 75% water, while bone is about 25% water and some water is found in cells. Water is essential to the human body. Not only is water part of the makeup of the body it is also a vital part of the body’s functions. Water is in the bloodstream cells and the spaces between the cells. Water moves back and forth between body compartments in order to equalize the concentration of dissolved particles. When the concentration of particles in one compartment is higher than in another compartment, water will move toward the compartment with the most dissolved substances. This is called osmosis. Osmosis not only drives the movement of water from one body compartment to another, but it also allows water from the diet to move from the fluid of the gastrointestinal tract into the blood. Water is a part of the life line that makes the body function properly. Water bathes the cells and cleanses and lubricates internal and external body surfaces. Surfaces like the eyes and joints. The saliva in the mouth makes it easier to chew and swallow food. Blood is made up mostly of water and travels throughout the body delivering oxygen and nutrients to cells and returning waste products to the lungs and kidneys to be excreted. Water also helps regulate body temperature. Water in the blood helps regulate body temperature by increasing or decreasing the amount of heat lost at the surface of the body. When the body’s temperature starts to get higher, the blood vessels in the skin dilate, causing blood to flow close to the surface where it can release some of the heat to the surrounding air. Water is also a regulator if body temperature with sweat when body temperature rises, the brain triggers the sweat glands in the skin to produce sweat which is made mostly of water. As the sweat evaporates the heat is lost and the body is cooled. In a colder environment, the blood vessels in the skin constrict, restricting the flow of blood near the surface of the skin keeping the body warmer. In the body, water has many functions in chemical reactions. In some of the reactions, water actually helps maintain the proper level of acidity in the body. Water also participates in the chemical reactions that join small molecules together and break large molecules apart. The body does not only depend on water for proper body function but is also made up of water and it is important to maintain the amount of water put into the body. Maintaining the right amount of water in the body is can be done by regulating the amount of water we consume. Most water intake comes from the fluids that are consumed in foods and drinks. Solid food provides water, mostly from fruits and vegetables but also in just about everything that is eaten. To maintain the right amount of water in the body a balance must be reached between intake and excretion. Loss of water from evaporation, urine and feces needs to be replaced with the intake of water. The sensation of thirst is a signal from the body that there is a need to replace water. Thirst is caused by dryness in the mouth and is a sign from the brain that there is a decreased amount of fluid and an increase in the concentration of dissolved substances in the blood. This is where the powerful urge to drink comes from. While this is not the only time there is signals to increase water intake, there are other times where it is important to drink. During times when there is loss of water from evaporation like during exercise especially when it is hot it is important to increase water intake. Some times when drinking it is not good for the body, as when drinking alcohol. Drinking alcohol actually increases water loss leaving the body with what is called a hangover. The effects of consuming too much alcohol are due to dehydration. Caffeine and caffeinated drinks cause the body to increase urine excretion and contribute to dehydration. While intake of fluids is important, choosing the right fluids is equally important. Balancing important electrolytes in the body also helps balancing body fluids. Electrolytes such as sodium, potassium and chloride are key electrolytes in the body and help regulate fluid balance in the body. Thoughts, movements and responses in the body requires that a nerve impulse speed through the body and target a cell. Nerve impulses are created by the movement of sodium and potassium ions across the nerve cell membrane. Sodium and potassium are both positively charged ions. The imbalance of these ions outside the cell membrane, are forces that attract sodium to the inside of the cells. When the nerve cell is at rest sodium stays outside the cell. When the nerve is stimulated the cell membrane becomes more permeable to the sodium allowing the sodium into the nerve cell. Thus, the positive charge inside the cell increases and the electrical charge at the location is reversed. This triggers an increase in sodium permeability on the adjacent patch of membrane. The change in sodium permeability and electrical charge continues to spread down the nerve as a nerve impulse and then to a muscle cell can cause a muscle contraction. So drinking enough to dilute the imbalance in sodium in the blood is important to maintaining proper levels of electrolytes in the body. Dehydration is a depletion of body water and it will cause symptoms more rapidly than a deficiency of any other nutrient. Dehydration can be life threatening, even the smallest changes in the amount of water in the body. The human body can only last a few days without water. When water loss is great enough to reduce blood volume, the ability to deliver oxygen and nutrients to the cells and remove waste products is affected. There are many symptoms of dehydration including thirst, headache, fatigue, loss of appetite, dry eyes and mouth, and dark colored urine. More extreme loss affects the ability to think, physical performance. Later symptoms are nausea, difficulty concentrating, confusion and disorientation. During times of increased risk to dehydration it is important to drink regularly to replace water loss. Even during periods of inactivity it is important to consume fluids to help maintain proper fluid balance. Keeping the human body healthy and well balanced paying attention to the body’s signals and maintaining fluids that makeup the body is the key to success.

References
Grosvenor, M. B., & Smolin, L. A. (2006). Nutrition: Everyday choices. Hoboken, NJ: John Wiley & Sons