Water is vital to human health. When we are born, our bodies are made up of about 78 percent water. The amount drops as we age, but even as adults, our bodies are about 60 percent water, and they rely on it to work efficiently. Water is essential for regulating body temperature, building and repairing cells, digestion and much more.
When you’re dehydrated, your body is losing more fluids than it is taking in. Dehydration can cause headaches, dizziness, dry mouth, muscle aches, vomiting and more. In severe cases, it can lead to liver failure, heart attacks, strokes and even death. In fact, dehydration is the number one cause of death in children worldwide.
Luckily, most people recognize the warning signs before reaching critical levels. However, it is easy to become dehydrated more quickly under certain conditions. Dehydration is especially common on hot or dry days, when you’re sick and whenever you sweat, such as during exercise or yard work. It’s also more common for people with certain preexisting health conditions, like diabetes, and for “desk jockeys” – people who spend eight hours or more per day at a desk and forget to get up and replenish their water supply during the work day.
In the emergency room, the most common causes of dehydration we see are from vomiting and diarrhea. Usually, the first sign of dehydration is feeling thirsty. It’s the body’s way of telling us it needs a drink! When you start to feel thirsty, you’re already down – your body is running at a deficit.
Another common warning sign is a lack of urination. If the body is getting enough fluids, it will keep producing fluids. In general, a properly hydrated adult urinates every couple of hours. If it’s been three hours or more, you may be dehydrated. Children usually urinate more frequently than adults, but the same rule applies here. If your child hasn’t urinated in a couple of hours, he is probably dehydrated.
Sweat can also be a good warning sign. If you’re sweating a lot and suddenly stop but are still in the heat or exercising, etc., then you may have a more serious case of dehydration.
What to do:
In general, drink plenty of water. If you feel thirsty or aren’t urinating regularly, then you probably need more. How much water is needed is based on your size, gender and medical history. For example, men tend to need more water than women to stay hydrated, as do people with higher body masses. In addition, if your blood sugar is high, the kidneys can pull water out faster, so people with diabetes may get dehydrated quicker than someone who does not.
What you eat and drink can make a big difference as well. Caffeine and sugar can cause dehydration, so if you drink a lot of coffee or soda or eat a lot of sweets, you may need to drink more water. Some sports drinks also have a lot of sugar in them, so if you’re sweating a lot and need to replenish fluids and electrolytes, look for a sports drink with no or low sugar.
If it’s going to be a hot or dry day, or you know you’re going to be sweating a lot, drink water beforehand and continue at regular intervals before you get thirsty as then you are already dehydrated. This allows your body to store much needed fluid.
When to call the doctor:
If you experience serious dehydration warning signs as an adult, see a doctor immediately. These include not urinating for several hours; feeling dizzy, lightheaded or so thirsty; or having continuous diarrhea, vomiting or fever.
With infants, bring them to a doctor immediately if they experience any of the following: no wet diapers for several hours, crying but no longer producing tears, continuous diarrhea and/or vomiting, dry tongue or their “soft spot,” or eyes look sunken in.
Jay R. Woody, M.D., FACEP
Dr. Jay Woody is an owner of Legacy ER & Urgent Care, and is a well-known and widely-published authority in the field of emergency medicine. He is the former Regional Medical Director of a freestanding emergency medicine practice, as well as a sought-after speaker and peer reviewer for the Texas Medical Foundation.
Dr. Woody has contributed to such vital references sources as Prehospital and Disaster Medicine Journal, Academic Emergency Medicine, the Texas Emergency Bulletin and two textbooks: Medical Response to Terrorism: Preparedness and Clinical Practice, and AAEM Emergency Medical and Family Health.
He also has been a featured presenter at the Southeast Society of Academic Emergency Medicine, the Nordic Congress on Disaster and Emergency Medicine and the Clinical Excellence in Emergency Medicine Conference. He teaches frequently and has helped further emergency practice alongside his peers at UT Southwestern Medical Center and Emergency Medicine Educations Systems.
When not working, writing or speaking, Dr. Woody enjoys sea kayaking, exercising, adventure travel and photography. He lives in Frisco with his wife Katrina and their two children.
Education / Training
- 1994 B.A. Texas Tech University ; Lubbock, Texas
- 1998 M.D. University of Southwestern Medical School; Dallas, Texas
- Emergency Medicine Residency at Parkland Memorial Hospital / Children's Medical Center
Professional Credentials and Memberships
- Fellow of the American College of Emergency Physicians
- Board Certified by the American Board of Emergency Medicine
- COLA Certified Laboratory Director
- American College of Emergency Physicians
- Texas College of Emergency Physicians