When Do You Need to Drink More Water?

Thirst is the desire to drink something. It can be triggered by the loss of fluid volume in and around cells and in the blood. Thirst is your body's way of saying you need water to avoid dehydration.

Thirst has a behavioral component as well and can be triggered by aromas and flavors, so just thinking about your favorite beverage can make you thirsty. It's also important to note that older people often have problems with the thirst mechanism and may not feel thirsty even when they're dehydrated.

There are some things that can cause bad breath like eating onions or garlic. But another potential reason is a lack of normal saliva production. Even mild dehydration can reduce saliva flow so if your bad breath is accompanied by a dry mouth, drinking more water throughout the day may help. Keep a glass of water by your bedside for nighttime relief, too.

Water is essential for brain function. Studies show that a loss of about two percent of your body fluid can cause a decline in mental function, so if you're having trouble concentrating, it may be time for a water break. 

Increased activity like exercise or physical labor can increase the amount of fluid lost when you sweat. It's best to drink two to three cups of water before your activity begins and drink about one cup of water every 15 minutes or so while you're active. You might need even more if you're working or exercising in extreme temperatures.

Water is essential for regulating your body temperature, so if you're outside on a hot day or stuck inside without air conditioning, you're going to need more water as the heat causes you to sweat more. Even if you're not active, spending the day in 90-degree temperature conditions could more than double your fluid requirement. And even more if you're physically active.

Air pressure is reduced at higher elevations and compared to being at sea level, people who live at 4,000 feet generally lose about eight ounces more fluid every day, mostly because of changes in respiration. The higher you go, the greater potential for fluid loss, so be sure to bring extra water if you're going for a hike in the mountains.

If you're sick with a fever, letting yourself get dehydrated isn't going to help, and it may make the fever worse. Sip water or other fluids to keep yourself hydrated. Also, see your health care provider if the fever lasts more than two days or you have other symptoms that don't go away.

Diarrhea can happen for a variety of reasons, including infections, irritable bowel syndrome, and inflammatory bowel disorders. But whatever, the cause, diarrhea can lead to dehydration. Drink extra fluids while you have diarrhea, and after, to remain hydrated.

Drinking too much alcohol will lead to a hangover the next day. While one or two alcoholic beverages shouldn't cause a problem, overindulging can result in dehydration, inflammation, a headache, and stomach irritation. Drink plenty of water while you're recuperating. And next time, drink water while you're partying – it may slow down your alcohol consumption.

Women who are pregnant need about ten cups of fluid every day. Some women retain extra fluid during their pregnancy and have some swelling, but that doesn't reduce the need for water. If you're pregnant, talk to your doctor about how much water you need every day.

Breastmilk is mostly water, so you'll need to drink extra water while you're breastfeeding. The Institute of Medicine recommends all breastfeeding moms consume about 13 cups of fluids every day. It doesn't all have to be water because any healthy beverages will fulfill your fluid need.

Caffeine is a diuretic, which means it makes you pee more, but your body adapts to moderate caffeine intake and the amount of water in your cup of coffee, or tea is more than enough to offset any fluid lost. But it's not clear what happens if you consume lots of caffeine without the fluid. There's probably some potential for dehydration if you're gulping down energy drinks and dancing it up all night without drinking extra water.