Exercise Intensity

One of the most common mistakes new exercisers make is in not measuring exercise intensity. Someone tells you that your workout should be a challenge, 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 lack of results). Exercise intensity refers to how hard your body is working during physical activity. For maximum health benefits, the goal is to work hard but not too hard. There is a variety of ways to measure your exercise intensity to make sure your body is getting the most out of every workout.

If you have a medical condition, are overweight, are aged over 40 years or haven’t exercised regularly in a long time, see your doctor for a medical check-up before starting any new exercise program.

There are ways to measure your intensity to ensure you are working in your “training zone” without killing yourself. The three most common ways to measure intensity are:

• Target Heart Rate

• Rate of Perceived Exertion (RPE)

• The Talk Test.

1. Target Heart Rate (THR)

Your exercise heart rate is the most precise way to measure intensity. Your target heart rate is a training zone—an estimate of where your heart rate should be to insure that you are training sufficiently. Training below your target zone may not be intense enough to burn sufficient calories, while training above your zone will force your body to burn calories inefficiently.

When you exercise as hard as you can, your heart beats at its maximum rate. If you're a healthy adult, strive to exercise at your target heart rate — between 60 percent and 85 percent of your maximum heart rate. If you have an irregular heart rhythm or you're taking medication that affects your heart rate, ask your doctor about the best way to measure your exercise intensity. Here's how to calculate your target heart rate:

Subtract your age from 220. This is your maximum heart rate.

Determine the low end of your target heart rate by multiplying your maximum heart rate by 0.6.

Determine the upper end of your target heart rate by multiplying your maximum heart rate by 0.85.

To check your pulse over your carotid artery, place your index and third fingers on your neck to the side of your windpipe. When you feel your pulse, look at your watch and count the number of beats in 15 seconds. Multiply this number by 4 to get your heart rate per minute. For Example, suppose you take our pulse and count 30 beats in 15 seconds; multiply by 4 to get 120 beats per minute.

To check your pulse at your wrist, place two fingers between the bone and the tendon over your radial artery, which is located on the thumb side of your wrist. When you feel your pulse, look at your watch and count the number of beats in 15 seconds. Multiply this number by 4 to get your heart rate per minute. If your heart rate is within the range you calculated above, you're exercising at about the right level. If your heart rate is too low, pick up the pace. If your heart rate is too high, back off a bit.

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.

Tips for using the target heart rate (THR) method:

• Periodically take your pulse during your exercise session to gauge your intensity level. If your pulse is within your training heart rate zone, you’re right on track! If not, adjust how hard or easy you are working out until you get into your zone.

• As far as time goes, try to sustain this intensity (not including your 5 minute warm-up or cool down) for AT LEAST 20 minutes (minimum recommendations for health and weight loss), and up to 45 or even 60 minutes. Of course, you would not start an exercise program with that much endurance, but you'll slowly build up. Aim for reaching this time/intensity 3-5 days per week.

• In addition to taking your heart rate manually, heart rate monitors are also a good way to observe your beats per minute to keep the exercise in the proper target zone. A heart-rate monitor is strapped around your chest and gives you feedback on a digital watch, telling you exactly what your heart rate is at a specific time in the exercise session.

• Your target heart rate (THR) range may not actually be the right exercise intensity for you. This method is age-related and not fitness-related. The more fit you become, the easier it becomes to work out in your THR range. Your ideal exercise intensity might be higher than the THR for your age group.

2. Rate of Perceived Exertion (RPE)

RPE may be the most versatile method to measure exercise intensity for all age groups. This rating relies on how hard you feel you’re exerting yourself during exercise.

The scale rates how you feel (both physically and mentally) as it relates to the intensity level. The scale ranges from 1 to 10, with the recommended RPE of 5-7 for most adult workouts. This means that at the height of your workout, you should feel you are working “somewhat hard”, nearing “hard”. Using the RPE works well because it is individualized based on your current fitness level and overall perception of exercise.

1 Rest

2 Very light

3 Light

4 Fairly light

5 / 6 Somewhat hard

7 Hard (heavy) 8 Very hard 9 Extremely hard

10 Maximal exertion

Tips for using this method:

• 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 if you do not have typical heart rate responses to graded exercise. These people include those on beta blocking medications, some cardiac and diabetic patients, pregnant women, and others who may have an altered heart rate response

3. Talk Test

The final method for measuring exercise intensity is the Talk Test. Like the RPE, the talk test is subjective and should be used in conjunction with taking a pulse. The talk test is quite useful in determining your comfort zone of 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 would be 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 several phrases 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 learning. Try your own Talk Test during your next workout (and compare it to your normal heart rate count 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.

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