• Brian Bender, PhD

Diseases Caused by Dehydration

Updated: Jun 5

“There is no doubt that dehydration is more common than you’d think.” - Jay Woody, MD, FACEP, chief medical officer of Intuitive Health and founder of Legacy ER & Urgent Care.

Approximately 55 - 75% of the body is composed of water. It is essentially for cellular homeostasis and for life.


Yet despite its importance, this vital part of our diet is often neglected. And it’s easy to see how this can happen on a regular basis.


Jay continues, “Do you feel thirsty reading this right now? Then you’re already dehydrated. By the time your body sends the signals that you’re in need of hydration, you’ll have to play catch-up to get the H2O you actually need.”


Often, dehydration is mild and easily remedied. But to maintain good overall health and wellness, it’s important to try not to become dehydrated constantly.


Dr. Livingood reminds us, “your body needs water to run it's muscles and keep its temperature under control, with long term dehydration we risk damaging our muscles, our heart, and experiencing other implications due to irregular body temperature. Additionally, one might experience extreme exhaustion and cramping.”


Chronic mild dehydration


Dr. Lina Velikova, MD, Ph.D., a medical advisor at Supplements101 says, “Chronic dehydration can cause nausea, headaches, muscle cramping. These symptoms can worsen depending on the dehydration levels. Needless to say, chronic dehydration leaves a toll on our body, and we should make sure to take enough fluids throughout the day.”



Poor hydration has been known to negatively affect athletic performance and reduce cognitive performance. Trista Best, a Registered Dietitian and Adjunct Nutrition Professor, says “proper hydration impacts our cognitive function and energy in a major way. Studies have found that even a mild form of dehydration, 1-3%, can impair brain function. This includes mood, energy, concentration, and memory. Slight dehydration can create feelings of anxiety and increase headaches. These side effects alone make a significant impact on overall quality of life.”


“Mild dehydration can lead to constipation as excess fluids are reabsorbed from the gastrointestinal tract. Stool becomes harder and drier which causes constipation. Mild dehydration may also affect mood and concentration.” Leann Poston M.D., M.B.A., M.Ed. of Invigor Medical. “Chronic dehydration can make it harder to maximize metabolic processes in the body, leading to weight gain.”


But it has also been shown that dehydration is associated with obesity, as well as cardiovascular disease.


Dr. Livingood continues, “neurological disorders can also be tied to dehydration, with blood volume being down due to lack of water leading to heart pressure being up causing severe damage to the heart over time. High blood pressure, urinary tract infections, cramping, muscle issues, electrolyte imbalances are all signs to look for when looking at dehydration or even mild dehydration.”


Chronic dehydration can also negatively affect your oral health.



“One of the symptoms of chronic dehydration is a lack of saliva. It may sound innocent but this condition, called dry mouth (or xerostomia), leads to serious complications in terms of oral health,” says Henry Hackney, Doctor of Dental Medicine and a member of the American Dental Association.


Dr. Hackney continues, “Bad breath and mouth sores appear first. Soon after, bacteria start to impact the tooth enamel, creating cracks and holes that result in cavities. At the same time, the lack of moisture is a problem. You can experience dryness and a burning sensation on your tongue, cracked lips, a hoarse throat, and inflammation in the mouth. If untreated, a chronic absence of spit leads to severe decay and teeth sensitivity.”


Dehydration and kidney function


“Kidneys need water from the body to remove the waste from our blood, which is not happening if we’re dehydrated,” says Dr. Velikova.


The National Kidney Foundation agrees with the risk dehydration poses on kidney health, stating that “some studies have shown that frequent dehydration, even if it’s mild, may lead to permanent kidney damage.”


Nicole DeMasi Malcher, MS, RDN, CDCES adds, “When you're dehydrated, your blood becomes more concentrated, leading to the potential short-term increase in blood sugar and imbalance of electrolytes. High blood sugar increases frequency of urination, and can make you more dehydrated. Lack of water also impairs the body's ability to flush out toxic waste and acid through the urine, which can strain the kidneys and increase the risk for kidney stones and urinary tract infections (UTIs). In severe cases of dehydration, acute kidney failure can occur.”

Dr. Livingood agrees. “Kidneys and urinary tract are also in danger of infections and severe damage due to a lack of nourishment that kidneys need.”


Complications of dehydration


When dehydration becomes severe, the effects of chronic dehydration may become more serious.


“While very mild dehydration is something that can usually be remedied at home with fluids and rest, anything more serious could warrant the need for immediate treatment at a local medical facility. Dehydration can become serious very quickly, so it’s important not to ignore the signs and seek out medical assistance right away,” says Dr. Woody, adding a list of signs to watch out for:


Signs of mild to moderate dehydration include:

  • Infrequent urination

  • Urine that’s dark yellow in color

  • Headaches

  • Muscle cramps

  • Feeling hot with skin that’s cool to the touch

Signs of severe dehydration include:

  • Dizziness or lightheadedness

  • Mental confusion

  • Extreme fatigue

  • Rapid heartbeat

  • Difficulty breathing

  • Chest or abdominal pain

  • Sunken eyes

  • Dry skin and lost elasticity

  • Inability to urinate, cry, or sweat

  • Extreme thirst

  • High fever

  • Fainting, loss of consciousness

  • Seizures

“In younger people mild dehydration may not cause any immediate problems but in certain individuals it can predispose them to kidney problems, including kidney stones, it can increase their risk for gout, and it can increase risk of urinary tract infections,” says Nikhil Agarwal, MD of Wellmed.


Dr. Lina Velikova, MD, Ph.D., a medical advisor at Supplements101, “Swelling of the brain. If you’re dehydrated but drink water after a while, your body will try to pull water back into cells, which in most severe cases, leads to cerebral edema.”


Jaime Hickey, an NASM and FSM certified personal trainer and registered dietitian, agrees. “Cerebral edema or brain swelling is caused by your body trying to pull too much water back into your major organs and causing the cells to rupture. This is especially dangerous when it happens to brain cells, this is why you need to have an IV add water back into your system if you allow yourself to become too dehydrated.”


“When we drink water, we lose the supply of the essential electrolytes, which send messages from our brain to our body, which leads to involuntary muscle contractions.” says Dr. Velikova.

Jaime continues, “seizures can be experienced if you lose too many electrolytes and your body can no longer carry the electrical signals it uses to communicate with your body. To prevent this make sure to add sodium and potassium into your water or drink a sports drink like Gatorade to add the electrolytes back into your bloodstream.”


Avoiding diseases caused by dehydration



Staying hydrated is an ongoing lifestyle behavior that should be next to healthy eating, regular exercise, consistent sleep, and reduction of stress. There are ways to tracking hydration, but it also can be done by integrating consistent hydration practices into your daily routines.


Nicole leaves us with some advice on staying hydrated throughout the day.


“Sip on water or other caffeine-free beverages throughout the day. There are a lot of factors to determine your exact water needs, but the easiest way to figure out how much you need is to drink half of your weight (in pounds). For example, If you weigh 150 lbs, you'll need around 75 ounces of water or 9-10 cups each day to stay adequately hydrated.”

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