Heart rate's around 90. Is that normal?

Heart rate refers to the number of heartbeats per minute. Normal people's heart rate is 60-100 beats per minute, most people's heart rate is generally around 70-80 beats per minute, but this heart rate is sinus rhythm, what sinus rhythm, sinus rhythm is the heart beat formed by the sinus node as a pacemaker. Sinus rhythm is affected by many factors, such as changes in body temperature, elevated body temperature can cause heart rate to increase, heart rate will increase during exercise, heart rate will decrease during sleep, heart rate will increase during eating, heart rate will increase during emotional pulsation and tantrums. Of course, some diseases can cause heart rate to slow down, such as hypothyroidism and coma. Heart rate in 90/min or so normal to see if the heart rate is sinus rhythm, or other rhythm, such as atrial fibrillation, if the atrial fibrillation heart rate in 90 beats/min or so, is abnormal. If sinus rhythm, heart rate is normal, depending on the situation to judge whether the heart rate is normal or not.