What we physicians tell patients should be based on evidence, but that doesn’t always happen. A good example is when patients ask what their pulse rate should be, and we tell patients between 60 and 100 — a range that has been in the medical literature for ages but is not based on science. Even the Mayo Clinic website on the internet wrongly says a normal pulse rate is 60 to 100.
Each time your heart contracts to pump blood through your arteries, a pulse occurs in your arteries that can be palpated and sometimes seen. You can check your pulse by lightly pressing the tips of your index and middle fingers against the carotid arteries in your neck, on either side of your wind pipe (trachea). You can also feel your pulse by placing the same two fingers against the radial artery, located on the thumb side of the palm surface of your wrist, about 2 inches back from the joint. While looking at your watch, count your pulse for 15 seconds and multiply by four, which gives you your pulse rate — the number of pulsations (heart beats) per minute.
In spite of the medical dictum of normal pulse being between 60 and 100, a resting pulse rate of 90 is clearly abnormal, and a rate in the 50s or even 40s can be very normal. For example, well-conditioned athletes have resting pulse rates in the 40s and 50s, and sometimes even in the 30s.
Dr. Michael Greger’s website nutritionfacts.org describes studies that show that for every 10 heart beats per minute over 60, premature death (death that occurs earlier than the average American man or woman) increases by 10 to 20 percent. If your resting heart rate is in the 90s, your rate of sudden cardiac death is five times higher — about the same risk as if you smoked. Conditions that can cause an elevated pulse rate include:
• Exercise — although if you are in good cardiovascular condition the rate should drop back to baseline within seconds after stopping exercise
• Poor cardiovascular conditioning
• Acute anxiety or stress (“flight or fight” response)
• Chronic stress, such as anxiety, depression, job or marital stress
• Anemia
• Low oxygen level
• Acute or chronic pain
• Dehydration
• Stimulants such as caffeine and ephedrine-like drugs in OTC cold preparations
• Hyperthyroidism (an overactive thyroid gland)
Unless you’re a well-conditioned athlete, be aware of conditions that could cause a slow heart rate — less than 60
• Heart block — a blockage in the heart’s electrical conduction system
• Hypothyroidism (an underactive thyroid gland)
• Certain drugs such as beta-blockers
Your pulse rate should be regular. If you have “skipped beats” or other irregularities, check with your PCP, who will order an EKG to determine what kind of irregularity you have — some are worrisome, and others aren’t. In summary, also check with your PCP if you have a regular but rapid heart rate of over 75 or so — or if your rate is below 60 unless the slow rate is due to excellent conditioning.
Retired physician Greg Feinsinger, M.D., is author of new book “Enjoy Optimal Health, 98 Health Tips From a Family Doctor,” available on Amazon and in local bookstores. Profits go towards an endowment to the University of Colorado School of Medicine to add prevention and nutrition to the curriculum. He is available for free consultations about heart attack prevention, diabetes reversal, nutrition, and other health issues. Call 379-5718 for an appointment. For questions about his column, email gfeinsinger@comcast.net.