Any form of cardio, like running, raises your heart rate to some degree. But, you may be wondering, how high is too high? If you look down at your heart rate monitor and notice the number 170, what is that telling you about your health and fitness?
Ahead, we explain what your heart rate should be when running — and what to do if it gets too high.
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What Is Heart Rate and Why Should You Pay Attention to It?
Your heart rate while exercising is measured by beats per minute (bpm) and is an indicator of the level of intensity and effort you're putting into your ongoing activity. Monitoring your heart rate during or after running can help you to check your fitness level and measure your progress.
It can also help you to determine and adjust the intensity of your running routine. This is because the higher your heart rate is during and after your miles, the more intense your running workout was.
A high heart rate during exercise verging on the maximum does present more risks and could be considered dangerous depending on a variety of factors. These include exercise tolerance, age, health and medical history.
How to Find Your Target and Maximum Heart Rate
The answer to the question, "Is 170 bpm bad when exercising?" is largely dependent on you as an individual. To help you figure it out, though, it's important to first determine your target heart rate and maximum heart rate.
You can figure out an estimate of your target heart rate for exercise (a healthy heart rate during exercise) by knowing your theoretical maximum heart rate. Your maximum heart rate is the number of beats per minute your heart can handle when working at its maximum. There are several different methods you can use to calculate your theoretical maximum heart rate.
One way is to take your age and subtract it from 220 (called the Fox Formula). This number gives you the average maximum heart rate for individuals in your age group, according to the American Heart Association (AHA). Keep in mind this calculation is just an estimate and may have a wide margin of error.
There are a few other ways to determine your max heart rate that take your age and sex into account to give a better idea of your maximum heart rate:
The most accurate way to determine your maximum heart rate is with a treadmill stress test at your doctor's office. But whichever formula you might favor, seek the advice of your doctor before you start an exercise program and monitor your heart rate when running.
Your target heart rate zone is between 50 and 85 percent of your estimated maximum heart rate, per the AHA. If you've been sedentary or are otherwise out of shape, this number is probably closer to 50 percent. If you're an athlete, it might be closer to 85 percent.
Here's a chart from the AHA that breaks down target and max heart rate by age group. You'll see that 170 bpm is within the "normal" range for either target or max heart rates for a few different age groups.
Target HR Zone
Average Max Heart Rate
100 to 170 bpm
95 to 162 bpm
93 to 157 bpm
90 to 153 bpm
88 to 149 bpm
85 to 145 bpm
83 to 140 bpm
80 to 136 bpm
78 to 132 bpm
75 to 128 bpm
You can determine if you're working at an appropriate level by gauging how comfortable you are while you run. If you can have a brief conversation, you're probably within your target heart rate range. If you can have a lengthy conversation or sing, you may be able run a little faster to maximize your workout. If you can't speak at all, slow down, because you may be working too hard.
When to See a Doctor
Going above your max heart rate while running is generally safe for short periods of time, as long as you don't have heart disease, high blood pressure, diabetes or are at risk for a heart attack, as LIVESTRONG.com has previously reported.
However, if your heart rate is at 170 bpm for long periods of time but you're in an age group where that's not considered normal, you should make an appointment with your doc to make sure nothing is wrong.
Additionally, if you notice any irregularities in your heart rate at any point, such as palpitations or skipping beats, stop exercising immediately and talk to your physician to rule out any medical conditions.
Get emergency attention if your racing heart is accompanied by dizziness, loss of consciousness, chest pain or shortness of breath.
A heart rate of 170 bpm while running can be a sign something's wrong if it falls above your maximum heart rate and you're experiencing symptoms like trouble breathing, dizziness, chest pain or lightheadedness.
If you have no known heart problems and your heart rate is at its maximum of 170 bpm, it's generally safe to exercise at this heart rate for a short amount of time. However, it's best to work out within your target heart rate zone most of the time, as this is an optimum heart rate. So, if 170 bpm falls within your target heart rate zone, you don't need to worry if you see this number.
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