If you’ve ever belonged to a gym, you probably noticed people who barely looked like they were working out. These guys and gals looked TOO comfortable, not even the tiniest bead of sweat rolling down their smiling faces. Plus, they were easily able to carry on a conversation as they did their leisurely workout. Sound familiar? More importantly, what were they hoping to accomplish?
Time is precious and such an approach is not the way to change your body or improve your fitness level. Without a little stress, your body doesn’t change. You need to get out of your comfort zone to transform your physique, yet do it in a controlled manner. Yet, how do you know if you’re exercising hard enough?
Monitoring Exertion When You Work Out
When you work out, you need a way to measure how hard you’re exercising. How much you’re sweating is not always a reliable indicator. These days, more folks than ever wear fitness trackers and monitoring devices to measure exercise intensity. However, you don’t have to go high-tech to determine whether you’re putting forth enough effort when you train.
Your heart rate is one indicator of how intensely you’re working and you can monitor it by simply checking a radial pulse periodically during your workout. To do this, stop exercising. Immediately place your fingertips on your wrist, just below your thumb, and count the number of beats for 10 seconds. Multiply that number by 6 to get your heart rate. To see how hard you’re working, compare your heart rate to your maximal heart rate. To get your maximal heart rate, you can use a simple formula:
206 – 88% of your age
The more familiar formula of subtracting your age from 220 isn’t, based on recent research or very accurate, especially for women. In fact, it can be off by as much as 15 beats per minute. So, use the above formula, for more accuracy. Another option, although not always practical, is to get your maximal heart rate measured via a treadmill stress test, but keep in mind that maximal heart rate goes down with age.
Once you know your maximal heart rate, compare the pulse rate you measured to that value. If you’re doing a high-intensity interval training workout, aim for an intensity that’s 85% to 90% of your maximal heart rate. If you’re doing moderate-intensity exercise, 55% to 65% of your heart rate max is appropriate. You just don’t want your heart rate to fall below 50% of your maximal heart rate or you won’t get a significant training effect.
Exertion Ratings
A heart rate monitor has the benefit of being an objective measure. You can also take a more subjective approach and use exertion ratings. It’s not high-tech or glamorous but it works. The most popular approach to doing this is to use the RPE or rate of perceived exertion scale based on a 1 to 10 scale. Here’s what the RPE scale looks like:
0 – No movement
0.5 – Just noticeable
1 – Very light
2 – Light
3 – Moderate
4 – Somewhat heavy
5 – Heavy
6
7 – Very heavy
8
9
10 – Very, very heavy. Only sustainable for a few seconds.
When you’re exercising at a moderate pace, you’d be around a 3 or 4. If you’re doing a HIIT routine, you might hover around a 7 or 8 during the active intervals. This assumes, of course, that you’re not a beginner. When you’re first starting out your active intervals might be in the 5 or 6 range.
Studies show that the “talk test” is another way to determine how hard you’re working. If speech is possible, but it’s difficult to speak in complete sentences, you’re working at an intensity that’s great enough to offer cardiovascular benefits. Once you reach the point where you can no longer say more than a word or two, you’ve reached your ventilatory threshold and are fueling your exercise anaerobically. This would be appropriate for the active intervals of a HIIT workout. Studies show that at the point you can no longer comfortably hold a conversation, you’re at around 90% of your maximal heart rate.
Which is the Best Approach?
Each approach to measuring exercise intensity has its advantages and disadvantages. The RPE scale has the drawback of being subjective, yet it’s straightforward and requires no equipment. A heart rate monitor gives you objective data but your heart rate can be affected by factors such as level of hydration, the temperature you’re working out in, and certain medications. For example, if you take beta-blockers for high blood pressure, these medications slow your heart rate and make it harder to reach your target heart rate. Even caffeine can impact your heart rate during exercise. If you take a medication that affects your heart rate, the talk or RPE scale may be more reliable.
The RPE scale and talk test work no matter what environment you’re exercising in and at what temperature. Plus, you don’t have to stop what you’re doing and feel for a pulse. It’s a simple way to monitor your exercise intensity and get more out of your workouts.
The Bottom Line
Whether you’re trying to improve your aerobic capacity through moderate-intensity exercise or your anaerobic capacity through high-intensity interval training, you won’t progress unless you work out at an intensity that challenges you. Some days you might take it easy but you also want to push yourself on non-rest days. A heart rate monitor will help you measure how hard you’re working, but you can also use the RPE scale or the talk test to ensure you’re staying on course. The feedback you’ll get is invaluable.
References:
Cleveland Clinic. “Rated Perceived Exertion (RPE) Scale”
The “Talk Test” Phil Block, M.S., and Len Kravitz, Ph.D.
Med Sci Sports Exerc. 2004 Sep;36(9):1632-6.
Current Opinion in Cardiology 29(5) · July 2014.
Journal of Sports Sciences, 2002, 20, 873-899
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High-Intensity Interval Training: How Intense Does It Have to Be?
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Exercise Intensity: How Good Are You at Judging How Hard You’re Exercising?
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Using Maximal Heart Rate to Measure Exercise Intensity – Is the Formula Flawed?
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