Your resting heart rate should average between 50 and 70 beats a minute. Athletes can have rates between 30 and 50 and still have healthy hearts, and your heart rate temporarily can go above 70 when you are sick, stressed or sleep deprived, but all people who have persistent resting heart rates greater than 70, non-athletes who have heart rates below 55, and anyone with a heart rate below 60 with heart palpitations, fainting , dizziness or other symptoms may want to check with a doctor. Resting heart rates greater than 70 are associated with increased risk for diabetes (Int J Epidemiol, Jun 2010;39(3):900–906), heart attacks, certain cancers and premature death (CMAJ, Oct 18, 2016;188(15):E384–E392).

The Research
• More than 6000 men were followed for more than 25 years. Those with resting heart rates greater than 73 beats per minute were 140 percent more likely to die from cancer than those with resting heart rates of less than 60 beats per minute (PLoS ONE, published online August 03, 2011).
• Of more than 53,000 men followed for almost 30 years, those with resting heart rates greater than 80 beats a minute were far more likely to suffer heart attacks and cancer than those with fewer than 60 beats a minute (Mayo Clinic Proceedings, 12/12/2013).
• 58 obese men and women exercised five times a week at 70 percent of their maximum heart rate for 45 minutes. In just 12 weeks they lowered their resting heart rates by five to nine beats per minute (Br J Sports Med, 2009; 43: 924-927).
• The Copenhagen Study of 3,000 men followed for 16 years found that those with a resting heart rate between 71 and 80 beats per minute were at a 50 percent elevated risk of death, between 81 and 90 beats per minute had double the risk, and resting heart rates over 90 beats per minute tripled the risk (Glob Cardiol Sci Pract, Oct 9, 2015;2015(3):33). Furthermore, high resting heart rates were associated with lower levels of physical fitness, higher blood pressure, overweight, and higher levels of circulating blood fats. The authors concluded that “a high resting heart rate is not a mere marker of poor physical fitness, but is an independent risk factor for disease.”

A High Resting Heart Rate May Predict Heart Disease
A strong heart pumps lots of blood with fewer beats, while a weak heart has to beat more often to pump the same amount of blood. A high resting heart rate may indicate that arteries are blocked or that there is heart muscle damage so the weakened heart has to pump more often to circulate oxygen to your body.

How a High Resting Heart Rate Relates to Cancer
Telomeres are the end caps of chromosomes that help to protect them from being destroyed when a cell reproduces. The longer your telomeres, the less likely you are to develop cancer, and people who exercise regularly have longer telomeres. Exercise also helps to protect the body from inflammation, a risk factor for cancer. The more intensely you exercise, the lower the heart rate and the greater the protection against inflammation.

How to Check Your Resting Heart Rate
To find out your resting heart rate, check your pulse when you first wake in the morning, before you get out of bed. You can use a heart rate monitor, a blood pressure cuff that includes a pulse check, one of the many fitness trackers that have a heart rate feature, or any watch that shows seconds. If you have a smart phone you can download a free heart rate monitor app. Set your device on your bedside table the night before so you do not have to move around when you wake up. If you are using a watch, place your fingers on the side of your neck where you feel a strong heartbeat. Count the beats for ten seconds and multiply by six. Do this for several days and take an average.

My Recommendations
A morning resting heart rate consistently over 70 is often a warning signal that you have a weak heart and may be headed for serious disease. If your resting pulse rate is over 70 beats per minute and you are not sick or taking stimulants, check with your doctor, particularly if you also have:
• LDL cholesterol greater than 100,
• blood sugar greater than 145 mg/dL one hour after eating,
• systolic blood pressure greater than 120 at bed time, or
• a C-reactive protein greater than 10 mg/L.

Athletes often have exceptionally low heart rates indicating a strong heart, but in non-athletes a low heart rate can be caused by damage to the heart’s electrical conduction system or muscle. If you have a resting heart rate of less than 60 and are not a regular exerciser, or if you are regular exerciser and have a bedtime systolic blood pressure greater than 120 or below 90, chest discomfort, dizziness or fainting, a bad LDL cholesterol greater than 100, or any possibility of an irregular heartbeat, you should check with your doctor.