Researchers Find Heart Rate Worth a Thousand Words
Sept. 19, 2000 -- For those worried about their heart, here's some good news: A person's risk for having a life-threatening bout with heart disease can be determined easily and accurately using two simple, noninvasive tests. You've probably heard of one -- exercise stress testing, also known as treadmill testing. The other you probably aren't familiar with: heart rate recovery. Researchers at the Cleveland Clinic report their results with these two tests in the Sept. 20 issue of the Journal of the American Medical Association.
Heart rate recovery is a measurement of how much the heart rate falls during the first minute after peak exercise. It is routinely measured during millions of exercise tests every year. Doctors usually order these tests when they suspect that a patient may have a heart in trouble.
Patients are put on a treadmill and exercise to the point that they can't go on. It is then that the heart rate recovery is taken. Afterward, it's added to the picture created by how long the person can exercise and what the heart rate was doing during the exercise test. This big picture can give doctors a pretty accurate idea of how well the heart is working.
The healthier a person's heart is, the quicker it returns to its normal beat; the less healthy the heart is, the longer it takes it to recover from something like an exercise stress test.
"One simply subtracts the heart rate two minutes after exercise from the heart rate at the end of exercise," says Michael S. Lauer, MD, director of the Cleveland Clinic Exercise Laboratory in Ohio and the lead researcher of the study.
Lauer and colleagues found that people with an abnormal heart rate recovery, which consists of a score -- or decrease -- of 12 or less beats per minute, were at a greater risk for death from heart disease than those with normal heart rate recovery, which is a decrease of 15 to 25 beats per minute.
Both tests are very simple and, according to these authors, will give a good picture of who should be treated aggressively for heart disease and who should be reassured that they are at little risk.
"If a patient has a normal heart rate recovery and normal exercise stress test, I tell them that everything looks great for them, that they have a risk for having a major life-threatening problem of less than one half of 1% per year," he says. "If the test is abnormal, the risk moves up to 3% or 5% per year. That means we really have to get to work."
So what are those who have abnormal heart rate recovery times to do? According to Lauer, they should be even more motivated to become healthier and reduce their risk for heart disease.