Dehydration can influence your mental functioning, your heart rate and your ability to regulate body temperature and blood pressure. If you lose even 1% of your body weight in water, your physical performance is affected and you feel tired. If you lose 2-4%, your mental functioning is affected; and in cases where more than 10 percent is lost, a medical emergency can result, and if not reversed, can lead to death.
Infants, young children, people with certain chronic health problems and elderly adults are more susceptible to the effects of dehydration, which is why it’s important to practice safe measures to prevent dehydration in yourself and others.
So how much water do you need?
This depends on your age, percent of body fat, general health, diet, temperature of the air around you and your level of activity. You lose water through urine, sweat, feces and the air you exhale.
The Institute of Medicine (IOM) suggests that the average healthy woman drink about nine cups a day of liquids and the average man about 13 cups a day.
How does dehydration occur?
You can become dehydrated by not consuming enough fluid from foods and beverages. These are some other conditions that also can make dehydration more likely:
- Sweating during exercise that is not compensated by drinking extra fluids; exercise even in cold weather can cause sweating
- Hot, humid weather
- High altitude, which causes rapid breathing and increased urine output
- Illnesses such as poorly controlled diabetes, and illnesses that cause vomiting, diarrhea or fever
- Certain medications
Each of these conditions alone can contribute to dehydration; a combination of them can cause it to arise more quickly.
Although caffeine does cause you to urinate more frequently, the effect is short-term and does not typically cause dehydration. Both caffeinated and non-caffeinated beverages can be used as sources of water.
Alcoholic drinks also can make you urinate more frequently, but, like caffeine, this increase is short-term and usually does not cause dehydration if you drink in moderation.
Symptoms of Dehydration
A dry or sticky mouth, caused by too little saliva
Less urine than normal, or no urine for eight hours. Urine that is darker than usual may indicate dehydration; diet, medications, and vitamin supplements can also affect urine color.
Few or no tears
Dry, cool skin
Fast heart rate
Lethargy, irritability or fatigue
Listlessness or coma; this is a sign of severe dehydration.
How to Recover from Dehydration
Drink at least 12 8-ounce glasses of fluid every day to overcome dehydration. Fluid may include water; orange juice; lemonade; apple, grape, and cranberry juice; clear fruit drinks; electrolyte replacement and sports drinks; and teas and coffee without caffeine.
Be sure to follow up with your health care provider if you don't get better within 24 to 48 hours.
When to seek medical attention
Very dark urine and little urine output
Dizziness, weakness, confusion, fainting