Answer: Normal increase in heart rate that takes place during a person breathes in.
Step-by-step explanation:
Sinus arrhythmia can be defined as medical condition in which the hear rate of a normal human being increases during inspiration.
This is a normal response of body which is usually seen in children. This is a response that is generated either during the exercise conditions or during the time of hypoxia.
Thus, the abnormal heart beat in an human being is known as sinus arrhythmia.