The heart rate of a healthy toddler can vary tremendously. During times of illness or stress, a 17-month-old may experience a shocking elevation in heart rate. Many otherwise-healthy toddlers simply have above-average or below-average pulse rates. In general, temporary increases in heart rate are harmless. However, when an abnormally high (or low) heart rate is sustained over a long period of time, it may indicate a medical condition or a functional abnormality in the child's body. Concerned parents should contact a paediatrician with any concerns relating to a child's pulse rate or heart rhythm.
Differences from Adults
Many parents grow concerned about toddlers' heart rates because they tend to be much faster than adults'. Parents should never assume that a normal adult heart rate is also the target range for a young child. A heart rate of 180 beats per minute, which would be alarming in an adult, is normal for a three-week-old baby. Likewise, a 17-month-old may have an apparently rapid heart rate that is actually within normal parameters. Slow heart rates (under 50bpm) may be normal for some adults, but dangerously low for a young child.
Average Pulse Rate
The National Institutes of Health offer guidelines for doctors evaluating the vital signs of children. The average pulse rate for a child between one and two years of age is 110-115 beats per minute, but there can be significant variances. A 17-month-old''s normal heart rate can range from 80 to 150 beats per minute. Every child's body is different, and some toddlers may consistently have heart rates on the high or low end of the spectrum. Except in special circumstances, variations in a toddler's heart rate are harmless; a slightly fast or slow pulse is rarely symptomatic of a serious illness.
Many factors can temporarily elevate a 17-month-old's heart rate. Active, curious children may experience an increased heart rate during and after playtime, with a slowdown during times of rest and sleep. Stimulants, including caffeine and theobromine (found in chocolate,) can cause a temporary elevation of heart rate. Children can also experience a quicker pulse when they are anxious or upset; a 17-month-old having a tantrum will almost invariably experience a sharp increase in heart rate. Anxiety may contribute to "white coat tachycardia", which causes many patients -- both children and adults -- to have quicker heart rates during a medical exam.
In toddlers, tachycardia (an abnormally fast heart rate) can be difficult to identify, since so many toddlers have a naturally rapid pulse. In general, a doctor may suspect clinical tachycardia in a 17-month-old whose pulse rate is consistently above 170-180 bpm. Even in these cases, a diagnosis of tachycardia is not necessarily grim: many toddlers with tachycardia are perfectly healthy and experience no significant health problems. After diagnosing tachycardia, a paediatrician may investigate possible underlying causes, including thyroid disease, heart abnormalities, and disorders of the central nervous system.
Bradycardia (slow pulse) is much less common in toddlers. An average 17-month-old will have a heart rate of 80 beats per minute or more, but anything above 70 is still generally recognised as acceptable. A toddler whose heart rate is consistently below 50 may be diagnosed with bradycardia. Like tachycardia, bradycardia can be caused by a variety of conditions, including abnormalities of the circulatory, endocrine and central nervous system.