increase heart rate

My son is 7 year old with normal health and doing well.but during running his heart rate and respiratory rate increases and he cannot play more than 20 minutes continuously.My pediatrician told that his heart sounds are normal and there is no murmur.please advice me what is the cause and what other test are needed.

[Marie M Gleason, M.D.]

It would be impossible to tell you the cause of exercise limitation in a child based on limited information.  Some children fatigue early due to inadequate fluid intake prior to exercise.  Some children develop exercise-induced asthma that limits their breathing and they stop earlier than usual.  The heart rate and respiratory rate are supposed to increase with exercise.  We would expect the heart rate to go up to 180-190 beats per minute (bpm) with peak exercise in a child.  if it goes well over 200 bpm, it could be a rhythm problem (unlikely).  Getting a baseline ECG and CXR might be helpful. Then discuss things further with your doctor.

[drsandeepgulati]

thanks ,what is CXR?

[Marie M Gleason, M.D.]

sorry:  CXR is a chest x-ray.  ECG is an electrocardiogram.