Your age, sex, location, and fat index (BMI) will determine how much water you need and how much you can retain. The average human body is between 55–60% water.
You may think that water is needed by the body only as a medium for blood. But an adult’s brain and heart are about 3/4 water, roughly the amount of moisture in a banana; even seemingly dry bones are 31% water; muscles are about 70%; while lungs are 83% much like an apple. Water lubricates our joints, eyes, and internal organs, regulates our body temperature, and serves as a medium to nourish different parts of our body.
If you are diabetic or are an alcoholic, you can dehydrate more easily than others.
We lose water through sweat, urine, stools, and even exhaled breath. When we lose it in excess of what we consume, we put ourselves at a risk of dehydration. Drops in energy, mood, skin moisture, blood pressure, and signs of impaired cognition follow suit.
What Happens When You Don’t Drink Enough Water?
Here are signs you should look out for to understand if your water intake needs a boost:
1. You Feel Thirsty Often
The sensitive coordination between our tongues and brain neurons has been fine-tuned over eras of evolution to help maintain the right water balance. When you’re water reserves are running low, your body gives you an all-too-familiar signal – thirst. Your lips and mouth will feel dry, too.
You may not feel thirsty till you are 1% or 2% dehydrated already.
But here’s the twist. Much to our surprise, most of our fluid consumption is not really thirst driven. Fluids are part of our meals (soup, milk) and beverages (tea, coffee) mostly because of habit, a norm of social gatherings, or irresistible flavors. This means we may tend to ignore actual thirst signals. What’s more is that as we age, we tend to feel less thirsty.
So, while thirst is an easy-to-identify indicator of dehydration, we may easily dismiss it till we’re way past mere warning signs. This is also why we may start getting dehydrated before we realize we’re actually thirsty.
2. You Urinate Less Frequently And Your Urine Is Dark In Color
Your kidneys are crucial in maintaining your body’s water levels. Considering that most body fluid is lost through urine, it is understandable why.
Low water levels cause sensory receptors in the brain to signal the release of anti-diuretic hormones. On reaching the kidneys, these hormones create cellular water channels called aquaporins that allow the blood to hold back more water. This is turn concentrates your urine and decreases the number of times you urinate or feel the urge to do so.
If your urine is any color other than a pale yellow or if you urinate fewer than 5 or 6 times a day, you need to investigate your water intake and take action.
The longer the intervals between your visits to the john, the darker your urine gets. You should be concerned if your urine is dark yellow with a strong odor.5If it is brown or reddish or if you don’t urinate for 8 hours in a stretch, see a doctor.
3. You Feel Constipated
In addition to reduced physical activity and low intake of dietary fiber, mild dehydration also can be a risk factor for constipation. With lesser water available to encourage bowel movements, you may find it difficult to pass stools.
4. You Develop A Weak, Rapid Pulse
When you’re not drinking enough water, your blood volumes decrease. Your heart has to compensate for this decrease as it tries to maintain consistent blood flow throughout the body. This is nothing short of overworking your heart. You may, thus, develop a weak, rapid pulse and experience palpitations. In very rare but severe cases of dehydration, this may even prove fatal.8
Caution: It is important to bear in mind that an accelerated heart rate is not an exclusive symptom of dehydration. It may be indicative of more serious heart complications. If a glass or two of water does not help calm you down, seek immediate medical help.
5. You Tire Easily And Are Often Confused
Carrying forward from the previous sign, an overworked heart may cause you to tire easily and experience heat exhaustion.
In one study, women deprived of fluids for 24 hours were less alert, felt more drowsy, tired, and confused. In another study, men experienced similar symptoms when they lost fluids equivalent to 1.6% of their body weight.
6. You Can’t Think And Mood Swings Make It Worse
Even mild dehydration can affect how you perceive daily tasks – walking to the supermarket, typing out an Excel sheet, or even leisurely reading a novel. If you don’t drink enough water, these simple tasks may require a conscious effort to concentrate.11 Women seem to be more affected than men in this regard, it is not yet clear why.
7. You Have Migraine Headaches
Water deprivation has been pinned as a trigger for migraines, along with the increased irritability and impaired concentration that it brings with it.
Individuals suffering from water deprivation-induced migraine headaches find relief on drinking water within 30 minutes to 3 hours.
As your blood vessels try and work with the lower volumes of blood when you are dehydrated, they may constrict to maintain a steady blood flow. Parts of your brain may even actually shrink due to intracranial dehydration. This is why some people may experience severe headaches.
8. Your Skin Remains Tented When Pinched
Pinch the skin of your lower arm or abdomen. If it doesn’t spring back immediately and stays tented for half a second or more, you are likely dehydrated.
Your skin is 30% water, serving as a natural waterproofing for your body. If you’re not drinking enough water, you compromise your skin’s elasticity. Water demands within the body are prioritized to important internal organs, drawing water away from the skin. Dried, shriveled skin and skin that looks gray or feels cool to touch is often consequential.
9. You Feel Lightheaded
Less water in your body can translate to a fall in blood pressure and, in severe cases, even fainting.15 This is like the head rush you feel when you sit or stand suddenly.
Dehydration Doesn’t Cause Muscle Cramps
If you indulge in intense physical activity, playing a sport or maximizing your workouts, you have probably experienced involuntary muscle twitching that develops into cramping at some point. A common condition affecting endurance athletes is exercise-associated muscle cramps (EAMC). It was previously believed that dehydration and salt (sodium) losses were responsible for the severe cramps, however, recent research suggests otherwise.16 A neurogenic malfunction associated with increased running speed and previous cramps seem to be the real trigger.