In general, as we age, the heart rate may gradually decrease with the reduction of activity, etc. The normal heart rate range is 60-100 beats/min. The heart rate of 90-year-olds may fluctuate up and down in the normal range, and it is normal if the heart rate is between 55-100 beats/min and there is no dizziness, palpitations, etc. As 90 year olds are of higher age, they have declined in physical function, metabolic rate and heart function, which may slow down the heart rate, but this slowdown can reduce the oxygen consumption of heart muscle cells, which is good for relieving myocardial ischemia and also for protecting the heart. 90 year olds’ heart rate is related to whether they suffer from primary diseases, their emotional state, exercise and their own physical quality, etc. When there is no other discomfort, the heart rate may slow down further during sleep and calm state, and may increase after emotional excitement or activity. Regular monitoring of heart rate helps to help understand the heart status and physical condition of 90-year-olds, which facilitates health promotion and timely treatment.