Q. I'm a man in my 50s. I'm in good shape and I exercise regularly, but I have a high resting heart rate. Is this cause for concern?
A. Your heart rate changes from minute to minute. It depends on whether you are standing up or lying down, moving around or sitting still, stressed or relaxed. Your resting heart rate is how fast your heart beats when you are relaxed and sitting still.
To answer your question, there is cause for concern. Based on a recent study, even fit men with higher resting heart rates may have a higher risk of early death.
The study followed nearly 2,800 middle-aged men for 16 years. Men whose resting heart rates were 80 or more beats per minute died earlier, on average, than men with a resting heart rate of 65 beats per minute.
Experts have recognized the link between faster resting heart rates and heart disease and shorter lives for the past few years. Until recently, the leading explanation has been that resting heart rates in the 60 to 70 beats-per-minute range most often reflect better fitness. And with better fitness you are less likely to develop heart problems and more likely to live longer.
The new study found that higher resting heart rates meant shorter life expectancy -- even in fit people. This was true even for men who exercised regularly when researchers factored in age and health habits.
Regular exercise does lower the resting heart rate. But even among regular exercisers, there are those with resting heart rates in the range of 55-75, and those with higher rates. In this study, those folks with higher rates were likely to die younger.
So what else causes a higher resting heart rate, besides not being fit? Genes and aging play a role. In my experience, there are some people who respond to the challenges of their daily lives by releasing a lot of the adrenaline hormone. Adrenaline raises heart rate, and constant high levels in the blood may make the heart more irritable.
People who smoke or drink too much alcohol generally have higher resting heart rates. Stress, medicines and medical conditions also influence heart rate.
Discuss your resting heart rate with your doctor at your next visit. In the meantime, you can start to lower your heart rate on your own:
• Exercise more: When you take a brisk walk, swim or ride a bike, your heart beats faster during the activity and for a short time afterward. But exercising every day gradually slows your resting heart rate.
• Reduce stress: Meditation, tai chi and other stress-busting techniques can lower your heart rate over time.
There are medicines that can lower your heart rate. The most widely used are beta blockers. These medicines are effective in treating high blood pressure. In people with known heart disease, they reduce the risk of future heart problems.
To my knowledge, there are no studies of whether people who just have high resting heart rates would benefit from taking beta blockers.
• Dr. Komaroff is a physician and professor at Harvard Medical School. Send questions to AskDoctorK.com.