Thirst isn’t a foolproof sign of dehydration. Your age, the weather and the activity you’re involved in can all interfere with your thirst response. But losing just 1.5 percent of your total water weight is considered “mild dehydration,” and can lead to fainting, accidents, injuries and more. So how else can you tell when it’s time to drink up?
We asked Samuel Nickles, MD a surgeon at Summerville Medical Center and Palmetto Adult and Children’s Urology in Charleston, South Carolina about dehydration red flags other than thirst. Grab a cool glass of H2O if you experience any of these surprising signs.
Brain Fog and Exhaustion
Not on your A-game today? Even slight dehydration could be to blame; it can reduce concentration, cause fatigue, worsen mood and lead to headaches, according to a study from the Journal of Nutrition.
The risks of severe fluid loss are well known, but researchers were curious about the mild dehydration you might experience in daily life. How risky is it really if you skip a few glasses of water? Researchers controlled hydration levels in 25 young women at rest and during exercise. The women who were less hydrated scored lower on mood and reasoning tests. They also reported difficulties concentrating and completing their work on those days.
Hunger You Just Can’t Satisfy
Mild dehydration can mask itself as hunger and might make you more prone to sugar cravings, according to some experts.
On the other hand, staying well hydrated can trick you into feeling full, says Dr. Nickles. Your satiety level, or feeling of fullness, is influenced by your stomach contents—regardless of whether you consume solids or liquids. That means drinking water could curb your appetite, he explains.
Researchers need to learn more about why hunger and thirst sometimes get confused. One explanation: since dehydration can hurt your ability to think clearly, it could make it harder to judge between the two sensations.
Saliva keeps your mouth naturally fresh by rinsing away odor-causing bacteria and food particles. Dry mouth from dehydration lets debris build up on mouth surfaces and contributes to foul-smelling vapors.
Prevent bad breath by:
- Sipping from a personal water bottle throughout the day
- Munching on high-fiber, hydrating fruits and vegetables like apples, pears and carrots
- Chewing sugar-free gum between meals to stimulate saliva production
Dry, Flaky Skin
Dehydration can keep a layer of your skin called the stratum corneum from receiving the moisture it needs. That can lead to a dull, dusky appearance, along with stretched pores, fine lines and flakiness.
Even if your skin is oily, it’s still possible to be dehydrated. In fact, dehydrated skin is prone to excess oil and breakouts as oil glands try to make up for the lack of moisture.
Keep your skin glowing by:
- Drinking a large glass of water instead of, or before, your morning coffee
- Skipping nicotine, alcohol and excess caffeine
- Avoiding long, hot showers, which can wash away your natural oils and dry your skin out even further
“Dehydration causes your blood pressure to drop, which reduces vascular tone in your brain and may lead to headaches,” says Nickles.
Vascular tone refers to how tight your blood vessels are. Low blood pressure means less blood and less oxygen being carried to brain cells; the vessels in your brain widen to try to increase the flow. These changes can trigger migraine headaches.
Drinking enough water may help prevent migraines, according to a study from Neurology. Chronic migraine suffers who drank about four extra cups of water per day experienced 21 fewer headache hours during the study period than those who didn’t up their H2O intake.
“Urine color is influenced by several factors, including hydration,” says Nickles. “Typically if your urine is a pale straw-yellow, it means you're well hydrated. If it becomes a little too yellow, it means you should drink some water.”
Here’s what your pee color could indicate:
- Clear or pale straw-yellow: You’re a water all-star, keep up the good work.
- Honey, cloudy yellow or amber: You may be mildly dehydrated. Chug, chug, chug!
- Dark yellow, orange or brown: You’re severely dehydrated or you could have a condition that requires medical attention. Drink plenty of water and call your doctor if the dark color persists.
How Much Water Do You Need in a Day?
The common advice to aim for eight glasses isn’t actually based on hard science. The truth is, the amount of water you need may vary depending on your age, health, activity level, gender and other factors. Studies over the years have come up with conflicting recommendations because of this.
However, if you’re a healthy adult male living in a temperate climate, three liters of water, or 13 glasses a day should keep you hydrated, according to the Institute of Medicine. For healthy adult women, 2.2 liters, or nine glasses should do the trick.