Knowing your heart rate at any time is easier than ever. What are the best ways to use this instant information?
There are many ways to track your heart rate nowadays, from fitness watches such as Garmin and Apple to activity trackers.
These devices use photoplethysmography sensors to measure your pulse. A light on the watch or tracker's underside shines onto the skin of your wrist and refracts off the blood flowing beneath. A sensor then translates that information into a pulse reading.
It's simple, fast, and reasonably accurate. But is this information valuable?
"Measuring your heart rate is an easy way to gauge your health in real time, as it provides a snapshot of your heart function," says Dr. James Sawalla Guseh, director of the Cardiovascular Performance Fellowship Program at Harvard-affiliated Massachusetts General Hospital. "Whether you are healthy and active or have a heart condition, these numbers can guide your workouts and at times highlight irregularities that you should have checked out."
Pointing a finger at your heart rate
Don't have a heart rate monitor? Use your fingers. Lightly press the index and middle fingers of one hand on the opposite wrist, just below the base of the thumb. Or lightly press the side of the neck, just below your jawbone.
To calculate your heart rate, count the number of beats in 15 seconds and multiply by four. Repeat three times and average the number for a more accurate reading.
Keep in mind that some situations can cause your resting heart rate to temporarily rise or fall. The best time to check it is right after you wake up before getting out of bed.
Feel the beat
Traditionally, a normal resting heart rate -- the number of heart beats per minute while at rest -- ranges from 60 to 100 beats. But many healthy people have a resting heart rate in the 50s.
Knowing your heart rate at any given time, especially during workouts or any type of aerobic activity, is essential for people who need to be careful about overexertion and high exercise intensity, such as those diagnosed with coronary artery disease or other forms of heart disease.
"If you fall into this category, consider asking your doctor for a so-called 'exercise prescription' that specifies a good heart rate goal during exercise and an upper limit you should not exceed," says Dr. Guseh.
For healthy older adults, monitoring heart rate can help maximize workout efforts. National guidelines recommend at least 150 minutes of moderate-intensity exercise per week.
Moderate intensity is 50% to 70% of your maximum heart rate, according to the American Heart Association, but the range can vary among individuals. In general, the greater your fitness level, the higher your moderate-intensity percentage range.
The most commonly used formula to calculate your maximum heart rate per minute is 220 minus your age. "For most people, increases in exercise intensity should be gradual," says Dr. Guseh. "As you exercise, you can use your heart rate monitor to see if your effort is adequate to stay within your desired target range, or if you need to increase the intensity or slow it down."
(Some monitors let you program desired levels and sound an alarm if your heart rate suddenly goes too high or too low.)
You can also use this information to track your progress. "If your average heart rate begins to go down, that's a sign of improved cardiovascular fitness," says Dr. Guseh.
Fast and slow
Another way to use heart rate monitoring is to look for values that are too high or too low, particularly at rest.
Consistently unusual resting heart rates above 100 beats per minute or below 50 beats per minute, particularly if you feel unwell, require a conversation with your doctor.
A fast rate could be triggered by exertion, dehydration, stimulants, anxiety, or medication. It may also be a sign of infection, an overactive thyroid gland, or anemia.
In addition, a fast heart rate may result from atrial fibrillation, a common heart rhythm abnormality that can emerge with age and is a frequent cause of stroke.
A slow heart rate is an expected side effect of certain heart and blood pressure medications, such as beta blockers and certain calcium-channel blockers.
Less commonly, an underlying heart condition, an underactive thyroid, or Lyme disease can be the reason. You also might experience nonspecific symptoms like lightheadedness, sudden fatigue, or brain fog.
"If you notice a slow heart rate along with new symptoms, it's worth discussing this with your doctor," says Dr. Guseh.
By Harvard Men's Health Watch