Most of us know that water is essential to support life and that our bodies depend on water to function properly. And many of us have heard that we should drink "at least 8 glasses of water every day." But did you know that fluid needs actually vary from person to person and depend on several factors?
Because our bodies lose water in a number of ways – for example, through sweat, urination, and other bodily functions – we need to replace it each day through beverages and foods. On average, men should drink about 13 cups (3 liters) of fluids per day and women should drink about 9 cups (a little more than 2 liters). Young children and older adults, and people who live in very warm climates, are very active, or are in poor health all have different fluid needs.
Dehydration – a condition that occurs when your body lacks water – can impair your body's ability to carry out normal functions and make you feel tired. Not drinking enough, losing too much fluid (e.g., through excessive sweating, vomiting, diarrhea, or urination), or both can cause dehydration. Certain medical conditions, including uncontrolled diabetes and infections that cause high fever, increase the risk for dehydration.
Dehydration can range in severity from mild to severe. According to the National Institutes of Health (NIH), symptoms of mild to moderate dehydration include the following:
- Dry mouth, thirst
- Dry, cool skin
- Muscle cramps
- Reduced urine output or dark-colored urine
To prevent mild to severe dehydration, drink plenty of fluids every day – especially when it's hot, before/during/after exercise, and when you have an illness that causes fever, vomiting, or diarrhea. Don't wait until dehydration symptoms develop.
If you're having difficulty drinking or keeping fluids down, try small sips of water or a sports drink that contains electrolytes and/or ice chips. Pay close attention to the fluid intake of young children and older adults. If you suspect dehydration, contact your health care provider.
Symptoms of severe dehydration include the following:
- Absence of urination or amber-colored urine (dry diapers in babies and very young children)
- Confusion, irritability
- Dizziness, lightheadedness
- Dry skin
- Fast heartbeat, rapid breathing
- Lack of sweat/tear production
- Listlessness, loss of energy
- Loss of consciousness
- Sunken eyes
Call 9-1-1 immediately if any of the symptoms above develop. Without treatment, severe dehydration can cause seizures, permanent brain damage, and death. Treatment usually involves intravenous (IV) fluids.
If your health care provider suspects dehydration, he/she will check for the following signs:
- Lack of skin elasticity, skin that returns slowly to shape after pinching
- Low blood pressure (hypotension), blood pressure that drops upon standing after lying down
- Rapid heart rate
- White finger tips
Diagnostic tests that may be performed include blood tests, urine tests, and others to monitor kidney function and determine the cause for dehydration.
If dehydration is detected and treated promptly, most people recover completely.
Source: U.S. National Library of Medicine, National Institutes of Health (NIH)