When you work out, especially at a high intensity, your heart rate speeds up to deliver more oxygen to your hard-working muscles. The extent to which your heart rate rises varies with your fitness level, age, and the environment you’re working out in.
Some medications, like beta-blockers used to treat high blood pressure, can affect your exercise heart rate. Beta-blockers cause resting heart rate to slow and make it harder to reach your target heart rate during exercise.
How fit you are matters too. As you become fitter from a cardiovascular standpoint, your heart rate won’t speed up as much at a given exercise intensity because your heart has become a more efficient pump and can pump more blood with each heartbeat.
A normal resting heart rate is between 60 and 100 beats per minute, but during a workout, your heart rate may more than double. This increase in heart rate is normal as your heart speeds up because of the added demands of exercise. After you stop your workout, your heart rate gradually comes down. Once your muscles are no longer working as hard, your heart doesn’t need to either, so it slows. In fact, how quickly your heart rate drops after exercise is an indirect marker of heart health. It also says something about how aerobically fit you are.
What a Prolonged Elevated Heart Rate after Exercise Means
Your heart speeds up and slows down in response to input from your central nervous system. During exercise, your sympathetic, or “fight or flight” component, takes over. Hormones like epinephrine and norepinephrine released in response to stress cause your heart to beat faster and more forcefully.
Once you stop exercising, your parasympathetic, or “rest and relax” component takes over and your heart rate slows. If you’re healthy and in good cardiovascular shape, your heart rate will slow down faster after a workout. For example, athletes usually have a rapid heart rate recovery.
What if your heart rate doesn’t come down quickly? You finished your workout 5 minutes ago and your heart is still racing. This phenomenon is called a slow recovery heart rate. Research shows heart rate recovery after exercise may be a marker of poor heart and metabolic health. For example, studies show people who have a slow heart rate recovery are at greater risk of heart attacks and cardiac death. Research also links a slow recovery heart rate with a higher risk of mortality from all causes.
How do you know if your heart recovers from exercise too slow? A study published in the New England Journal of Medicine found that heart rate recovery of less than 12 beats during the first minute after a workout is a predictor of a higher risk of cardiac death, but that’s not all. People with a slow heart rate recovery have a 2-fold greater risk of dying over the following 6 years.
A heart that’s slow to recover after exercise raises a red flag for other health problems. A study showed that slow heart recovery after exercise is associated with an increased risk of metabolic syndrome, a precursor to type 2 diabetes. So, a heart rate that stays up after exercise could be a cause for concern and something to discuss with your physician.
However, factors such as dehydration and fatigue also make it harder for your heart rate to recover and give you a false reading. In addition, health problems such as an overactive thyroid gland can elevate heart rate and slow heart rate recovery.
How to Check Your Heart Rate Recovery
Here’s a method the YMCA uses to measure heart recovery is the step test:
Place a 12- inch box on the floor.
Step up and down off the box at a pace of 24 steps per minute for 3 minutes.
At the end of 3 minutes, measure your heart rate for 15 seconds, and multiply the value by 4. Relax and let your heart rate comes down.
Then, recheck your heart rate at 1 minute and subtract the value from the first heart rate. The difference is your heart rate recovery at one minute.
An average heart rate recovery is between 15 and 20. If your heart slows less than 12 beats per minute after exercise, it’s a slow recovery and a red flag that you may be at a higher risk of cardiovascular disease. If your heart rate drops over 20 beats per minute after exercise, it’s a marker of good cardiovascular health and a low risk of cardiac death.
What the Results Mean
A prolonged elevated heart rate after exercise, as confirmed by a slow heart rate recovery, suggests you may be at higher risk of metabolic syndrome or heart problems, but factors like dehydration, excessive fatigue, and stress can affect the results too.
If you measure your heart rate recovery, make sure you’re well-rested and are drinking enough liquids beforehand. The first thing in the morning isn’t a good time since most people wake up mildly dehydrated and that will slow heart rate recovery.
Also, certain medications, like beta-blockers, can affect the results and give you an unreliable reading. Still, it’s a useful test you can do at home that says something about your future health risks.
It’s best to do the test several times on different days and average the values. Also, recheck your recovery heart rate every few months and record the value. As you become fitter, how fast your heart rate recovers should improve.
The Bottom Line
Recovery heart rate is a useful test to see where you stand from a health and fitness standpoint. Plus, it’s a test you can easily do without special equipment. Some fitness trackers also measure heart rate recovery after exercise, but it’s not clear how accurate the data is.
References:
Merck Manual. 18th edition.
Journal of the American Heart Association. February 18, 2020. Vol 9, Issue 4.
J Korean Med Sci. 2006 Aug; 21(4): 621-626.
N Engl J Med 1999; 341:1351-1357, DOI: 10.1056/NEJM199910283411804.
VeryWellFit.com. “How to Use Recovery Heart Rate for Fitness and Health”
Journal of the American Heart Association. May 5, 2017. Vol 6, Issue 5.
Exp Physiol. 2010; 95:431-440.
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