Normal sinus rhythms range from 43 to 102 beats per minute in men, 47 to 103 beats per minute in women and 110 to 150 beats per minute in children, states UpToDate. Sinus rhythm speeds up with physical activity and slows down with the cessation of activity.
An irregularity in the sinus rhythm is called sinus arrhythmia, adds UpToDate. If the rhythm is faster than the normal range, it classifies as sinus tachycardia. The term for sinus rhythm that is slower than normal is sinus bradycardia.
Sinus rhythm refers to pace that the sinus node sets for the heart, as described by the British Heart Foundation. To set the pace, the sinus node sends electrical signals to the chambers of the heart to contract them. The signals travel through the atria and to the ventricles.