The normal resting heart rate for a one-to-three-year-old is 70 to 110 beats per minute, according to the Kids Health website. Doctors consider a heart rate higher than 110 beats per minute to be elevated. Most toddlers' heart rates will stay at the lower part of this range, but a number of conditions can cause tachycardia – an unusually fast heart rate – in toddlers. If your child experiences prolonged or regular episodes of increased heart rate, it is important to take him to his doctor for an evaluation.
Certain conditions can force your child's heart to work harder to supply her body with oxygen. A toddler's heart rate will increase with exercise or activity. Fever can also cause tachycardia due to the higher energy needs of her body organs during illness. Stress, especially fear and anxiety, can also cause an elevated heart rate. If your toddler experiences difficulty breathing, due to asthma, viral illnesses like croup or allergies, you might also notice an increase in her heart rate.
Your child's diet can also affect his heart rate, according to Dr. Hasan Abdallah of the Children's Heart Institute. Due to picky eating patterns, many toddlers fall short of iron and develop anemia – a condition characterized by a lower-than-normal number of red blood cells. Since the red blood cells carry less oxygen than normal, your toddler's heart needs to work harder to supply oxygen to the brain.
If your child regularly experiences tachycardia, it is important to find out the cause. The American Heart Institute indicates that the treatment of arrhythmias – or abnormal heart rhythms – in children depends upon its type. Sinus tachyardias, the normal increases caused by illness or exercise, generally need no treatment and resolve on their own once you identify and correct the cause. Abnormal arrhythmias caused by heart problems might need treatment with medications or surgery.
The most common abnormal arrhythmia in children, according to the American Heart Institute, is supraventricular tachycardia, which causes a fast heart rate involving both chambers of the heart. The institute offers reassurance that this condition is not a life-threatening problem for toddlers or adults. Most doctors only use medication to treat the condition if your child experiences prolonged or frequent episodes.
Ventricular tachycardia – an arrhythmia that originates in the lower chambers of the heart – is often a sign of underlying heart disease. The condition rarely occurs in children, but can be life-threatening. Diagnosing and evaluating the condition often requires specialized testing, including intracardiac electrophysiologic procedure -- an invasive test in which doctors place electrodes inside of the heart.