Drinking plenty of water is essential to your health: It helps your organs perform their vital functions, regulates your body temperature, lubricates your joints, and helps rid your body of waste, among other things. And with so many important functions hanging in the balance, it doesn't take long for problems to arise when you're inadequately hydrated, experts say.
"Dehydration is when we start trending toward a negative fluid imbalance," explains Natasha Trentacosta, MD, sports medicine specialist and orthopedic surgeon at Cedars-Sinai Kerlan-Jobe Institute in Los Angeles. "In its most extreme form, we don't have enough fluid in our body to carry on with the chemical reactions and body functions to sustain life," she adds.
As water leaves the body, salts, minerals, and other electrolytes are left behind in higher concentrations than before. "This throws off the electrolyte balance in the body which can be detrimental to the cellular functions of our bodies," Trentacosta explains.
Recent polls suggests that 75 percent of Americans suffer from chronic dehydration, and for many, the problem goes undetected until complications arise. However, there are several signs and symptoms that can tip you off to a problem before then. Read on to learn the six telltale signs that you aren't drinking enough water—plus, how much you'll need to drink to avoid a problem.
1. You're fatigued or your mood dips.
It's easy to overlook some of the early signs of dehydration, or to attribute them to the stresses of everyday life. In particular, Trentacosta says that "feeling more tired or on edge" is a common signal that your hydration levels are dipping.
The doctor adds that while anyone may display this set of symptoms, it "seems to be greater in women than in men." She attributes the disparity to hormonal differences and body composition. "Women tend to have a lower percentage of water for their body weight compared to men, which essentially translates into women have less water to lose before becoming symptomatic." She says this means women may feel the impact of not drinking enough water before men do.
If you notice a feeling of fatigue, the first thing you should do is drink a tall glass of water, suggests Harvard Health Publishing. "When you are low on fluids, your body may feel tired and weaker than usual," their experts write. "Consuming a sufficient amount of fluids in beverages and water-filled food (such as fruits, vegetables, and soup) will help replenish the water your body loses throughout the day and can help you maintain your energy."
2. You often feel dizzy or lightheaded.
Another major sign of chronic dehydration is a feeling of dizziness or lightheadedness, says Vernon Williams, MD, sports neurologist, pain management specialist, and founding director of the Center for Sports Neurology and Pain Medicine at Cedars-Sinai Kerlan-Jobe Institute in Los Angeles, California.
"Recall a time in your life when you felt dehydrated. What was the first sign or symptom to present itself? Beyond feeling thirsty, you likely first noticed an initial symptom associated with your head," he tells Best Life.
Williams explains why the sensation occurs: Without adequate fluids, your blood volume goes down, which in turn lowers your blood pressure and prevents the brain from getting enough blood. This ultimately results in that woozy, disorienting feeling that so many people experience.
3. You get regular headaches.
Trentacosta says that if you get frequent headaches, this may be another red flag that you aren't drinking enough water. "Headaches are a very common early sign of dehydration," she says, adding that they're most common in women.
"When the body loses water, it loses water from the brain as well, causing it to temporarily shrink from the fluid loss. This causes pain as the nerve endings are stretched from the resultant shrinkage," she tells Best Life.
4. Your urine is dark yellow.
The color of your urine can tell you a lot about your hydration level, Trentacosta says. "The darker the urine, the more concentrated it is," she explains, noting that dark yellow or brown urine are signs of severe dehydration.
The doctor says that having dark urine is the result of "your body's attempt to conserve water loss by pulling out water through your kidneys. Having your urine output as clear as possible is a good indication of a well hydrated body," she adds.
5. You've experienced changes in memory or cognitive function.
You may also notice changes in your memory or cognitive function—though sometimes these changes are difficult to detect, says Williams.
"Even slight percentage decreases in brain hydration can result in much more significant percentage decreases in cognition. Consider this: Just a two percent decrease in brain hydration can lead to short-term memory loss. Longer-term dehydration can cause the shrinkage of brain cells. Over time, brain cell shrinkage can accelerate the brain's aging process and lead to degenerative cognitive conditions such as Alzheimer's sisease and dementia," he tells Best Life.
6. You're thirsty.
It may sound obvious, but thirst is the number one sign that you aren't getting enough water, says M. Ramin Modabber, MD, an orthopedic surgeon at Cedars-Sinai Kerlan-Jobe Institute in Los Angeles, California.
In fact, according to the Cleveland Clinic, being thirsty or having a dry mouth is not a warning sign that you will soon become dehydrated, as many people believe, but instead a sign that you're already mildly dehydrated. In light of this, your goal should be to stay ahead of the sensation by remaining adequately hydrated throughout the day.
According to the Mayo Clinic, men require an average of 15.5 cups of fluid per day, while women require an average of 11.5 cups to stay healthy. However, Modabber points out that it's important to monitor for signs of over-hydration or dehydration, and adjust to meet your own body's specific needs.