Why do children faint?
Feb 28, 2018, 10:51:37 AM CST Jun 8, 2018, 1:06:46 PM CDT

Why do children faint?

Fainting can be scary for parents to witness, but it occurs in up to 30% of healthy children and adolescents. Recognizing common circumstances can help put parents at ease.

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Teenage girl running stopping to catch her breath Teenage girl running stopping to catch her breath

Fainting, also known as syncope, occurs when there is a sudden drop in blood pressure, or heart rate, that results in brief loss of consciousness. It is more common than many realize, affecting up to 30% of children, particularly adolescents. It is more than twice as common in females than in males.

“Fainting can be scary for parents to witness, but most of the time it is not a cause for concern,” says LeAnn Kridelbaugh, M.D., president of Children’s Health℠ Pediatric Group. “However, there are some situations when you would want to discuss fainting with your child’s doctor. Parents should be aware of why fainting happens and what to look out for.”

What causes fainting?

Most of us don’t think about our autonomic nervous system, which controls our heart rate and blood pressure in response to sensors all over the body. As children and adolescents grow, this system is still developing and sometimes overreacts – causing them to faint when their blood pressure or heart rate suddenly drops.

“Fainting in teens can occur in common situations, such as after they step out of a hot shower,” Dr. Kridelbaugh says. “They may feel sick or dizzy, and it is common for them to appear pale and sweaty before they faint.”

Some reasons that might cause fainting include:

  • Situational triggers, such as prolonged standing in hot or crowded environments. These events are more likely with dehydration.
  • Physical triggers, such as seeing needles or receiving a shot. Another common trigger is hair brushing.
  • Emotional stress, such as fear or anxiety
  • Hyperventilation
  • Low blood sugar

It is unusual for children to faint before the age of 6 unless they have seizure disorders, heart conditions or have been holding their breath.

Fainting and sports

While fainting after exercise is not particularly concerning, fainting during exercise, such as while running, would be a cause for alarm. Those rare instances could signal a hidden cardiac issue, says William Scott, M.D., a pediatric cardiologist in the Heart Center at Children’s Health and professor of pediatrics at UT Southwestern. Other symptoms of concern include unusually rapid or irregular heart rates.

Sudden cardiac arrest in athletes is extremely rare, affecting 1 percent of the population at most,” Dr. Scott says. “Because symptoms may not show up until children get older and start to participate in competitive sports, it’s important to know your family’s medical history and discuss it with your child’s doctor. If you have a relative who died suddenly at a young age, that is something to discuss with your pediatrician before your child plays sports. Your doctor may refer your child to a cardiologist for further testing.”

Many organizations offer screening electrocardiograms and echocardiograms for young athletes, but not every child needs one before playing sports. “It is important to remember that screening tests cannot detect all dangerous heart conditions,” Dr. Scott says. “However, any parent who wants these tests for their child for reassurance should be able to get one.” 

Besides fainting, your young athlete’s doctor would also want to know if she experiences chest pain during physical exertion, unusual shortness of breath or tiring more easily than in the past.

What to do if your child faints

If your child faints, check to see if he or she is breathing OK. Position the child on their back and look for any injuries. If the child doesn’t recover fully in a few minutes, take him or her to the emergency room.

In the very rare circumstance the child is unresponsive, begin CPR and call 9-1-1. Every parent should know CPR and know that an AED (portable defibrillator) is available wherever children participate in sports.

If your child faints outside of exercise and does not appear to have any physical injuries, it may not be as urgent. Dr. Kridelbaugh recommends calling your child’s doctor to assess the urgency of the situation. Full recovery usually occurs within a minute, but the child may feel tired the rest of the day. For most children who faint, a detailed account of the event is very informative, and no tests are needed.

Learn More

The nationally renowned team of pediatric cardiologists and subspecialists at Children’s Health treat the whole spectrum of pediatric heart problems, with a commitment to excellence. Learn more about our programs and treatments.

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