Questions About Heart Rate

1. What is a heart rate? What does it indicate, and why is it important?

Heart rate (HR) is the number of heart beats calculated per minute. The heart is the source of life in the human body, so it is a very busy organ, working 24/7 with a total of about 80,000-110,000 beats per day. The average heart rate is 60-80 beats per minute. This is sufficient to keep all vital organs like the brain, kidney, liver, etc., functioning well by delivering oxygen to the tissues.

Basal heart rate usually indicates the condition of the subject; for instance, some athletes have a very low basal heart rate in their 30s. However, during exercise it rises  appropriately to reach maximum rates, and at the other end, patients who are deconditioned have elevated basal heart rates, an indication of deconditioning.

Heart rate varies constantly as it responds to our bodily demands and to surrounding conditions, as well as our daily activities. For instance our HR is at its peak during the active hours of the day and steadily slows during sleep.

Heart rate can also be regular or irregular depending on the presence of abnormal heart rhythms, like skipped beats from the upper or lower champers of the heart or atrial fibrillation, which is a very disorganized rhythm originating from the upper chamber of the heart.

2. How can one measure it?　

Heart rate is typically measured at the wrist, by placing two fingers between the bone and the tendon over your radial artery — which is located on the thumb side of your wrist. When you feel your pulse, count the number of beats in 15 seconds. Multiply this number by 4 to calculate your beats per minute.

There are also numerous gadgets like wrist bands and phone apps that can measure heart rate with decent accuracy.

In medical practice, most of the time, if a patient has some palpitations or feels skipped beats, the physician might order a Holter monitor which analyses heart beats for 24 hours and gives the average, minimum, maximum, and the number of skipped beats as well as the total heart beats per day.

3. What influences it, and how might someone achieve a normal heart rate?

Heart rate is controlled by the specialized part of the nervous system called the autonomic system that consists of the sympathetic and the parasympathetic systems. The sympathetic system is the "fight and flight system" that causes us to be active, and increases the heart rate. On the other hand, the parasympathetic system is mediated by the "Vagus nerve" which typically slows most of the vital organs in the body, including the heart and except for the gastrointestinal tract, that in turn slows the heart rate, and is naturally active at night and during sleep. Heart rate is also modified by circulating catecholamines that are released during times of stress, happiness, or exercise.

4. What is maximal HR and how can one determine and achieve theirs?

Maximum heart rate is measured by the equation 220-age. Regular exercise is the best way to maintain normal range of heart rate and heart rate responses.