Kids & Hydration

With the warm weather just around the corner, it is far more likely that children playing and exercising in the sun could experience dehydration and heat illness. Cardiologist Christopher Almond, MD, MPH, and Joshua Nagler, MD, an Emergency Medicine specialist at Children’s Hospital Boston, have some tips about the risks of dehydration and its opposite, over-hydration or hyponatremia.

What is dehydration?

Dehydration occurs anytime the body is using or losing more fluid than it is taking in.

How can a child become dehydrated?

The most common cause is an illness during which your child is vomiting or has diarrhea. But during warmer months, if your child is playing for long periods of time in high temperatures, under direct sun, or in high humidity without drinking enough fluids, he is also at risk.

Are kids at greater risk than adults?

Yes, they are at greater risk due to the fact that the surface area of a child's body makes up a larger proportion of her weight. This gives her more area on which to be exposed to heat and from which to lose sweat. Also, previous dehydration issues, obesity and a recent illness are additional risk factors. Children who are in poor physical shape, not used to heat, or using antihistamines or diuretics are also at increased risk for dehydration.

What are the symptoms of dehydration?

Thirst is frequently the earliest symptom, and can occur with only very mild dehydration. Fatigue, dry lips and tongue, dark urine color, decrease in urination, and the feeling of being overheated may also indicate that your child is dehydrated.

What are the dangers of dehydration?

When a child is dehydrated, the body is not able to perform all of its necessary functions. The more severe the dehydration, the more difficult it is for the body. As long as fluids are re-introduced in a timely fashion, this is easily reversible.

Is there anything else to keep in mind about dehydration?

Many people don't know this, but dehydration is cumulative. If your child is dehydrated on day one and does not properly re-hydrate, they are starting off day two already dehydrated. This effect can lead to more serious dehydration.

Are there other risks for heat exposure, besides dehydration?

In addition to contributing to dehydration, exposure to significant heat over an extended period of time, such as playing outside on very hot days, can also be harmful to children. Heat cramps, heat exhaustion, and heat stroke are all examples of heat-related illness.

Heat cramps in the abdominal muscles, arms and legs are the least serious effect of prolonged exposure to high environmental temperatures. Heat exhaustion is more serious, and can cause dizziness, nausea, headaches, vomiting, weakness, muscle pain and sometimes loss of consciousness.

Heat stroke is the most serious consequence of excessive exposure to high ambient temperatures. The body temperature will be 104ºF or higher, and the person may experience nausea, vomiting, seizures, disorientation or delirium, a lack of sweating and shortness of breath. In some cases, she may become unconscious or even go into a coma.

What should I do if my child shows signs of heat illness?

The best thing to do is to avoid heat illness. Be aware of the heat index, which is a measure of how hot it feels in degrees when humidity is added to the actual air temperature. If it is very high, use caution when letting your child play outside for long period of time. Keep water or sports drinks handy, and consider setting up a sprinkler to help cool him off.

If your child shows signs of heat illness, get her to a cool place and get her to drink cool liquids. Take off any extra clothing or equipment that might be causing excess heat, and put cool, wet cloths on her skin. If she is vomiting, give her small amounts of fluids frequently to help her keep it down.

With heat cramps, gentle stretching should ease any pain. Heat exhaustion requires the above treatments, as well as rest for the entirety of the day. Heat stroke is potentially deadly, and a trip to the emergency room is in order.

Is it possible to be over-hydrated?

Over-hydration, which is called hyponatremia, can occur, but it is not a large risk. With stories of over-hydration related to marathon running in the news, people are so worried about it that they overcompensate in the other direction and don't drink enough. This can lead to dehydration. The key lies in moderation.

What are the risks of over-hydration?

Although uncommon, when very large amounts of water are consumed, the sodium level in the blood can decrease. Sodium, an important electrolyte, is necessary for the nervous system and body tissues to function. This decrease can lead to life threatening illness, such as a change in mental status, seizures, coma and even death. A Boston Marathon runner died in 2002 due to hyponatremia, which has increased public awareness of this condition. However, it is important to recognize this condition is very rare.

What symptoms should I be looking for?

Symptoms of over-hydration are often non-specific. There is even some overlap with symptoms of dehydration. Early signs include nausea and general malaise. As the condition worsens, altered mental status and excessive vomiting can occur. If you think you or your child is over-hydrated, seek medical attention.

Who is at risk?

It is rare in young kids. Teenagers who play sports often have day-long practices in the summer, and they should be careful to drink the proper amount of water. Coaches today are fairly aware of over-hydration and dehydration problems, and will keep fluid intake in check.

How can I prevent over-hydration?

Drink a few ounces of fluids every hour or so, or when thirsty. If you are drinking every 10 minutes, you are probably drinking too much. If you're drinking only every few hours, you are at risk for dehydration. It's all about moderation.

Are sports drinks an appropriate fluid for my child?

While sports drinks contain electrolytes that can help replenish the body's sodium levels, in general, they are not protective against hyponatremia. This is a common misconception that athletes especially should be aware of.

Above content provided by Children’s Hospital Boston in partnership with Beth Israel Deaconess Medical Center. For advice about your care, consult your doctor.