Fitness Articles

Reference Guide to Exercise Intensity

An In-Depth Look at Heart Rate, RPE and the Talk Test

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One of the most common mistakes new exercisers make is not measuring the intensity of their cardio workouts. Guidelines say that aerobic exercise should be “moderate” or “challenging,” but what does that feel like? You might make the mistake of working too hard (which can lead to injury and burnout), or not working hard enough (which can lead to frustration from a lack of results).

When following an aerobic exercise program, there are three main ways to measure your exercise intensity: Target Heart Rate (THR), Rate of Perceived Exertion (RPE) and The Talk Test. This guide will examine each of these three measures in detail so you can choose which works best for you.

Target Heart Rate

Target Heart Rate (THR) is the most commonly used method for measuring exercise intensity—mostly because it’s easy to do and it’s also precise. Your THR is actually a zone or range that your heart rate should fall within to ensure that you are training aerobically. Training below your target zone may not be intense enough to burn sufficient calories or improve your cardiovascular fitness; while training above your zone means you’re working anaerobically (without oxygen) and inefficiently, which is also too intense for many people, especially beginners.

A Target Heart Rate range is listed in percentages, typically between about 60% and 85% of your maximum heart rate. But how hard you should work depends on your fitness level. In general, beginners should work at a lower range and advanced exercisers should work at a higher range. Keep in mind that some people have exercise restrictions due to injury, health conditions or medications that will affect your recommended intensity level, so always check with your doctor first.

Use the following as a guide for determining your intensity level:
  • Beginner or low fitness level: 50% to 60%
  • Intermediate or average fitness level: 60% to 70%
  • Advanced or high fitness level: 75% to 85%
When starting an exercise program, aim for the lowest part of your target heart rate zone (50 percent of your maximum) during the first few weeks. Gradually build up to the higher part of your target zone (75 percent). After six months or more of regular exercise, you may be able to exercise comfortably at up to 85 percent of your maximum heart rate. However, you don't have to exercise that hard to stay in shape.

There are two different formulas you can use to calculate your Target Heart Rate:

1. The Maximal Heart Rate Formula is most commonly used to estimate Target Heart Rate because it’s easy to do and easy to remember. This formula does not take into account fitness level, medical conditions, or other things that might affect your heart rate. It is a good estimate but may be less accurate than other methods.

How to Use the Maximal Heart Rate Formula
Calculate your Max Heart Rate: (MHR = 220-age)
  • Calculate your Max Heart Rate: (MHR = 220-age)
  • Plug your numbers into the formula, using percentages that reflect your fitness level (i.e. 50% to 60% for beginners and 75% to 85% for advanced), as indicated below:

2. The Karvonen Formula is one of the most effective ways to estimate your target heart rate, because it takes your Resting Heart Rate (a good indicator of your fitness level) into account. Because it’s slightly more involved than other formulas (see #1 above), it isn’t used quite as often. But our Target Heart Rate calculator uses this formula and does all the work for you! You can see the details of this formula below, or simply use our calculator to find your target heart rate.

How to Use the Karvonen Formula:
  • Calculate your Max Heart Rate: (MHR = 220-age)
  • Find your Resting Heart Rate (RHR). Prior to getting out of bed in the morning, take your pulse on your wrist (radial pulse) or on the side of your neck (carotid pulse) for one full minute. This is your true resting heart rate. Measuring at other times of day, even at rest, does not yield the same results. To help assure accuracy, take your resting heart rate three mornings in a row and average the 3 heart rates together.
  • Plug your numbers into the formula, using percentages that reflect your fitness level (i.e. 50% to 60% for beginners and 75% to 85% for advanced), as indicated below:

How to Use Your Target Heart Rate Information
Once you have used either formula above to calculate your Target Heart Rate range (in beats per minute), you must try to keep your heart rate within your range during your cardio activity.

Periodically check your heart rate throughout your workout to gauge your intensity level. There are two ways to do this:
  1. Take your pulse after you’ve been exercising for at least five minutes. An easy way to check your pulse without interrupting your workout too much is to take a quick 6-second count and then multiply that number by 10 to get your heart rate in beats per minute. If your pulse is within your training heart rate zone, you’re right on track! If you notice you are lower than the minimum, increase your speed, incline and/or intensity and count again. If you notice you are very high, decrease your intensity in some way.
     
  2. Wear a heart rate monitor. This is the easiest way to monitor your intensity because it does all the work for you—all you have to do is look at a digital watch to see your current heart rate in beats per minute and/or percentages (i.e. 65%).
Additional Tips for Using Target Heart Rate
  • Your target heart rate (THR) range is an estimate, and it may not be the right exercise intensity for you. It’s based on a formula and not everyone fits into the average. Your THR may change over time as you become more fit too, so consider reevaluating your range every few months.
  • Some medications (such as beta-blockers) can affect your heart rate during exercise. An exerciser taking beta-blockers may be working at a high intensity but might never reach her target heart rate. Therefore, people on this or similar medications should not use the THR method (see RPE and Talk Test methods below).
  • Talk to your doctor to determine the best exercise intensity for you.
Rate of Perceived Exertion (RPE)


Rate of Perceived Exertion (RPE) may be the most versatile method to measure exercise intensity for all age groups. Using this method is simple, because all you have to do is estimate how hard you feel like you’re exerting yourself during exercise. RPE is a good measure of intensity because it is individualized—it’s based on your current fitness level and overall perception of exercise. The scale ranges from 1 to 10, allowing you to rate how you feel physically and mentally at a given intensity level.


An RPE between 5 and 7 is recommended for most adults. This means that at the height of your workout, you should feel you are working “somewhat hard” to “hard.”

Tips for using RPE:
  • A great way to measure intensity (where appropriate) is by using both the RPE and THR methods. Try to identify where you fall on the RPE scale when your heart rate is between 50 – 70% maximum. This will allow you to accurately use only the RPE scale for measuring intensity when it is not feasible to determine your THR.
  • RPE can be the primary means of measuring exercise intensity for people who do not have typical heart rate responses to graded exercise. These people include those on beta blocker medications, some cardiac and diabetic patients, pregnant women, and others who may have an altered heart rate response.
The Talk Test

The final method for measuring exercise intensity is the Talk Test. Like the RPE, the talk test is subjective and quite useful in determining your aerobic intensity, especially if you are just beginning an exercise program.

Using this method, the goal is to work at a level where you can answer a question, but not comfortably carry on a conversation. In simple terms, you’re working out too hard if you have to take a breath between every word you say. Conversely, you would be exercising too easily if you could sing the chorus of a song without breathing hard.

Work at an intensity that allows you to breathe comfortably and rhythmically throughout all phases of your workout. This will ensure a safe and comfortable level of exercise. If you are breathless, or can't talk, you're working too hard! Lower the resistance level and slow down. If you experience dizziness or lightheadedness, you may be overexerting yourself and should stop.

The Talk Test has been confirmed as a simple and accurate method of gauging intensity that doesn’t require any equipment or special training. Try your own Talk Test during your next workout (and compare it to your Target Heart Rate if you’re skeptical). You may be able to replace your heart rate monitoring with this simple test during all of your workouts, or at least when counting your pulse is inconvenient.

Moderate Intensity vs. Vigorous Intensity

You may have seen recent talk in the media about the new guidelines for physical activity. The U.S. Government publishes these guidelines which discuss “moderate” and “vigorous” intensity. So what does that mean? Moderate intensity workouts provide health benefits such as reduced risk of high blood pressure, certain cancers, stroke and diabetes. Vigorous intensity workouts provide those benefits, plus aid in weight loss and increased muscle mass. Here is how to distinguish between the two:

Moderate activity ranges from 40-60% of someone’s max heart rate. For most people, that would be walking a mile in 14 to 23 minutes. Moderate-intensity activity causes a slightly increased rate of breathing, and it feels “light” to “somewhat hard”. Individuals doing this type of activity can easily carry on a conversation.

Vigorous activity elevates heart rate above 60% of your max heart rate. Walking a mile in less than 14 minutes, jogging, cycling, and playing endurance sports are all considered vigorous activity. These activities result in increased rates of breathing and sweating and feel “somewhat hard” to “very hard.”

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Member Comments

  • I too was told by the doctor that because I had always been an active obese person, my heart had adapted to my body so I would have trouble reaching the calculated heart rate. She told me instead to make sure I broke a sweat and that the exercise was maintained for at least 10 minutes and to use the talking test. Seems to be working for me.
  • Also want to add, when I started exercising by doing workouts regularly when I was about 45 (after spending years just taking care of my family and not thinking about myself), I took a class at the gym and pushed hard, as I was used to as a teen and 20-something athlete, and I got light-headed and had to sit down. I was determined to keep pushing that hard and that was what I needed to do to get back into shape. The wise instructor advised me to get a heart rate monitor and told me about HR targets for working out. Just like this article. And it has been very helpful to me and I have kept an eye on my heart rate while working out ever since.
  • I didn't read through all the comments because there are a lot - but the ones I read mentioned the target rate being too high. For me it is too low. I am 58 and a runner. My age puts me into a lower HR by the calculations - I have a resting HR of 63 and I am 58. 85 % is 147 and I can hit that pretty early into a regular workout. 100% would be 160 and I easily hit the 160s in long slow runs. I took my high end target from what my heart rate is at the end of a 5k race when I go all out for the last 500 meters and it is 210, so I consider that my 100% HR. In my workouts, I like to maintain in the 180s for at least 30 minutes
  • Thanks. Thsi article reminds me of how to calculate heart rate at various stages. Also motivates me - another piece of data - and will help me to get the most out of my walking.
  • JMB369
    This was a really helpful article.mI have bradycardia, which is a slow heartbeat. My resting heart beat is about 48 bpm, so moderate intensity fir me is about 100-110! I like the idea of checking this against PRE and the talk test, as I walk with a friend 2-3 times a week. This week I am starting the 69-day walk program, so I'll be using these guidelines.
  • Very helpful and easy to understand article. Thanks for posting it.
  • Extremely help , simple guide to make sure you are getting the most out of exercise
  • A very insightful article. I run and cycle and actually train in the 70-80% area. I have been doing this for a couple of years now and I find it works well for me. Thanks for the information.
  • Thank you so much for this article! I have been wondering about it, but haven't had time to look it up. Whenever I start exercising again I can't use the recommended heart rates. But after I've been back exercising consistently for a month, then I can start using it.
  • SHAHAI16
    I usually do the talk test or PRE, heart rate calculations don't seem to work for me. If I used the guidelines for that I'd never get in a good workout. My resting pulse is normal-to-high (78 last I checked) but I periodically check on the monitors on the gym machines (which admittedly I know are inaccurate) and my heart rate gets really high, like around 180 if I'm pushing myself, 150-160 if just walking on the treadmill at an incline. I have no idea why my heart rate gets so high, when I was in the military my workouts would push it past my "max" heart rate.
  • I do the exertion thing, I cannot hold a conversation though so I guess I am working too hard. I am out of breath most of the time while I am walking and especially when I get to go to the gym and use the elliptical or stair climber. I just know I have lost 21 pounds in about 4 months and still have close to 30 to go.
  • I can't use the target heart rate method either. I doubt my heart would handle it very well. I run out of breath long before I get there. I will do what I can do, and hope it is enough. I need to lose the weight, but am not willing to die trying.
  • Definitely cannot use the target heart rate method - my minimum would throw me into A-Fib if it got that high. I do use perceived rate of exertion and the talk test which both seem to work for me! Research all suggestions then listen to your body!!
  • Does this work for people who have a pacemaker/defibri
    llator? I don 't believe my heart rate is allowed to go over 80.
  • PUCAKNAPP
    The chart on page 4 has an error. The order should be---
    8. Very hard
    9. Extremely hard
    10. Maximum exertion
    http://www.cdc.
    gov/physicala
    ctivity/basic
    s/measuring/exertion.htm

About The Author

Jen Mueller Jen Mueller
Jen received her master's degree in health promotion and education from the University of Cincinnati. A mom and avid marathon runner, she is an ACE-certified personal trainer, health coach, medical exercise specialist and behavior change specialist. See all of Jen's articles.

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