Heart rate refers to the number of heartbeats per minute in a normal person at rest, also known as resting heart rate. It typically ranges from 60 to 100 beats per minute, though individual variations occur due to age, gender, or other physiological factors. Generally, younger individuals have faster heart rates, while the elderly have slower heartbeats than younger adults. Women also tend to have higher heart rates than men of the same age—all of which are normal physiological phenomena.At rest, the normal adult heart rate is 60–100 beats per minute, with an ideal range of 55–70 beats per minute (athletes typically have slower rates, around 50 beats per minute).
1. Tachycardia: An adult resting heart rate exceeding 100 beats per minute (generally not exceeding 160 beats per minute)is termed sinus tachycardia. It commonly occurs during excitement, agitation, or after smoking, alcohol consumption, or drinking strong tea or coffee. It may also appear in pathological states such as infection, fever, shock, anemia, hypoxia, hyperthyroidism, or heart failure, or following administration of drugs like atropine, epinephrine, or ephedrine.
2. Bradycardia
A resting heart rate below 60 beats per minute in adults (generally above 45 beats per minute) is termed sinus bradycardia. It may be observed in healthy individuals engaged in prolonged strenuous physical labor or athletes; or in conditions such as hypothyroidism, increased intracranial pressure, obstructive jaundice, and overdose of digitalis, quinidine, or propranolol-type medications.If the heart rate falls below 40 beats per minute, consider conditions such as sick sinus syndrome or atrioventricular block. If the pulse is irregular, weak, and irregularly strong, and the pulse rate is lower than the heart rate, consider atrial fibrillation.
3. Understanding Sinus Bradycardia Correctly
Many people experience sinus bradycardia with irregular pulses, which is normal for most individuals and generally not cause for concern. Sinus bradycardia refers to a heart rate below 60 beats per minute. Whether symptoms arise depends on the bradycardia's frequency and underlying cause.At rest, adults with heart rates between 50–60 beats per minute typically experience no noticeable symptoms. This is especially true for well-trained athletes and individuals engaged in prolonged physical labor, who may exhibit no symptoms even at resting rates around 40 beats per minute.
However, for most individuals, a heart rate between 40 and 50 beats per minute may cause symptoms like chest tightness, fatigue, and dizziness. If the heart rate drops to 35–40 beats per minute, hemodynamic changes occur, impairing blood supply to vital organs like the heart and brain. This can lead to chest pain, dizziness, fainting, or even sudden death.If you feel no discomfort, you need not concern yourself with an ECG reading of "sinus bradycardia with irregularities." However, if symptoms like chest tightness, fatigue, or dizziness occur, seek immediate medical evaluation through tests such as Holter monitoring or cardiac echocardiography to determine the cause of bradycardia. If the heart rate is excessively slow, implanting a pacemaker can alleviate symptoms and improve prognosis.