About two-thirds of your body is water, but you consistently lose fluids from breathing, urination, perspiration and defecation. You become dehydrated when you don't drink enough fluids to replenish your stores. Small fluid deficiencies don't generally cause noticeable side effects, but extreme fluid deprivation or chronic low fluid intake can cause serious problems.
Acute Dehydration Symptoms
Simply not getting enough fluids can cause dehydration, although you are more likely to become dehydrated if you are vomiting, have diarrhea or are sweating a lot. If dehydration becomes bad enough, you may begin to experience symptoms such as headache, thirst, dizziness, lethargy, dark colored urine, low to no urine output, constipation and a dry and sticky mouth. More severe dehydration can cause lack of sweat and tears, extreme thirst, very dry mouth, confusion, low blood pressure, rapid pulse, fast breathing and fever.
Your urine is made up of mostly water and it helps transport waste products from your body. If you don't take in enough fluids and your body doesn't produce enough urine, waste can build up in your body and lead to serious illness or death. Being dehydrated can also cause life-threatening kidney failure, which occurs when your kidneys have trouble shuttling out excess fluids and waste.
Electrolytes, such as sodium and potassium, are charged ions that help conduct electrical currents in your body. All cells in your body are dependent on an electrolyte balance. Not having enough fluid in your body is one way to throw off the balance. When your electrolyte level is off, your cells might not contain the right amount of water, your brain may not receive the right nerve impulses and your muscles may not work efficiently. Some potential effects of an electrolyte imbalance are involuntary muscle contractions and seizures.
Heat cramps, heat exhaustion and heat stroke often occur alongside dehydration. Your body's cooling response to high temperatures is sweating because sweat evaporates on your skin and draws heat out of your body. The problem is that if you don't get enough water to replenish the fluids that are leaving your body, your body begins to have trouble regulating a safe temperature. Some symptoms of heat injury are headache, dizziness, disorientation or agitation, fatigue, hot and dry skin, rapid pulse, hallucinations, seizure and loss of consciousness. Heatstroke, a life-threatening condition that requires emergency care, occurs when your temperature is 104 degrees Fahrenheit or higher.
Doctors generally recommend having 8 to 9 cups of water per day, according to MayoClinic.com. This water can be in water-rich beverages and foods that contain water. Rather than monitoring each cup you drink, you can help ensure that you aren't dehydrated by monitoring your thirst level and urine levels. Your urine should be light or colorless and you should rarely, if ever, feel thirsty. If you start to feel signs of mild dehydration, drinking water or a sports drink can help replenish your fluids. Get emergency medical care if you start to experience extreme thirst, shriveled skin, confusion and dizziness.