6 Signs You’re Not Drinking Enough Water

6 Signs You’re Not Drinking Enough Water

You need water to drive every chemical reaction in your body – and that’s a lot of reactions! You can last 3 weeks without food but only 3 days without water. Yet, it’s easy to get in a hurry and forget to drink enough water for adequate hydration. Drinking enough fluid is especially important if you exercise. Vigorous physical activity and working out in a warm environment depletes fluids from your body through sweating, your body’s primary means of cooling off. You also lose electrolytes as well. Not being adequately hydrated during a workout can even impact your workout performance.

Whether you’re exercising or simply carrying out your daily activities, staying hydrated is essential. Yet, dehydration is a tricky thing. You can be mildly dehydrated without feeling particularly thirsty. That’s why it’s important to replenish fluids throughout the day. Here are 6 signs that you aren’t drinking enough water.

Not Drinking Enough Water? You Feel Tired, Less Productive, or Moody

Feeling exhausted? A study published in the Journal of Nutrition showed that mild dehydration might be the cause. Low fluid intake can cause fatigue, lack of motivations, brain fog – and it can even bring your mood down a notch. With more severe dehydration, you may experience cognitive issues or even confusion. Studies show that fatigue can set at levels of dehydration of as low as 1-3%, just below the threshold where you start to feel thirsty. How many of us are walking around feeling tired because of low fluid status? If you’re not feeling motivated or productive, try drinking a large glass of water and see if your energy level improves.

Not Drinking Enough Water? Headache

You can experience a headache simply due to dehydration. However, a study published in the journal Neurology showed that migraine sufferers are particularly sensitive to mild fluid depletion. In fact, the study found that the odds of experiencing a migraine increased by almost 8% with each 9-degree rise in environmental temperature, presumably due to fluid loss. Another study of migraine sufferers found those who increased their fluid intake by 4 cups a day experienced 21 fewer hours of migraine pain over the course of the study.

Whether staying hydrated reduces other types of headaches, including tension headaches, isn’t clear, but keeping your blood volume high helps deliver more oxygen to the brain. When you’re dehydrated, you also can experience electrolyte disturbances that can trigger headaches.

Not Drinking Enough Water? Your Urine is Dark in Color

The color of your urine is a fair indicator of your fluid status and degree of hydration. If you’re adequately hydrated, your urine should be pale yellow or almost clear in color. If it’s yellow, deep yellow, or brown, you’re not drinking enough fluid. If you’re taking certain medications, like NSAID, staying hydrated is particularly important to maintain proper kidney function. NSAID can decrease blood flow to the kidneys.

Not Drinking Enough Water? You Feel Lightheaded or Dizzy When You Stand Up

When your plasma volume drops due to mild dehydration, you might feel a bit lightheaded or dizzy when you stoop down and get up or when you rise out of a chair quickly. This is due to a transient drop in blood pressure as well as a reduction in blood reaching your brain. It’s more common to experience this unpleasant sensation on a hot day when you’re not drinking enough or after a sweaty workout. It’s another reason to cool-down after a workout and replace lost fluids right away. Even better, sip fluids during your workout as well.

Not Drinking Enough Water? Dry Mouth and Thirst

A dry mouth is a common sign of dehydration. When your fluid stores are low, your salivary glands don’t produce enough saliva. In fact, dehydration affects all of your mucous membranes. You might experience a dry mouth as well as dry eyes and nasal passages. In babies who are ill, the medical staff often check the mucous membranes first as a quick indicator of hydration status.

How about thirst? You can’t always count on your sense of thirst to tell you when your fluid stores are dwindling, especially if you’re older. As mentioned, the mechanism that regulates fluid status and thirst doesn’t work as well as you age. So, you may need to drink at regular intervals rather than count on your sense of thirst to tell you when to drink.

Not Drinking Enough Water? Your Exercise Performance Isn’t What It Usually Is

It’s no secret that we lose fluid and electrolytes with exercise, especially in a hot or humid environment. So, fluid requirements are higher with exercise and in a warm environment. If you don’t replenish fluids, your exercise performance can suffer. When you’re not hydrated, your heart rate rises and exercise feels harder. In one study, participants experienced a 5% decline in aerobic capacity with a level of dehydration of 3%.

Mild dehydration can also negatively impact resistance-training performance. In one study, mild dehydration of 3% reduced the number of strength-training repetitions participants were able to do and made the workout feel harder. Plus, their heart rate recovery was slower. That’s not surprising since your heart has to work harder when you’re fluid depleted.

Are You at Higher Risk of Dehydration?

If you’re over the age of 60, you’re at greater risk of dehydration than a younger person. Not only do you not sense thirst as readily as someone younger, but your kidneys also don’t act as quickly to conserve water when you’re not drinking enough. You’re also at higher risk of dehydration if you take certain medications. Some blood pressure and heart medications cause your body to excrete more water and electrolytes, particularly sodium and potassium.

The Bottom Line

The focus of this article is mild dehydration. However, dehydration can be a life-threatening situation. Severe fluid loss, at its most extreme, can cause your kidneys and other organs to shut down. So, make replenishing lost fluids a priority. The Centers for Disease Control suggests that adults drink around eight 8-ounce glasses of water daily. If you exercise, you’ll need to adjust your water intake accordingly.



Nutr Rev. 2010 Aug; 68(8): 439–458. doi:  10.1111/j.1753-4887.2010.00304.
Live Science. “Mild Dehydration Triggers Moodiness & Fatigue in Women
Neurology. 2009 Mar 10;72(10):922-7. doi: 10.1212/01.wnl.0000344152.56020.94
NY Times Well. “Really? The Claim: To Prevent Migraines, Drink More Water
Authority Nutrition. “10 Signs and Symptoms of Dehydration”


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