Exercise intensity, along with duration, are two factors that people track when they work out. If you’re exercising at a moderate intensity, you need to work out longer to maximize the cardiovascular benefits of aerobic training. On the other hand, if you ramp up the intensity through high-intensity interval training, you can reduce the duration and still get benefits. In fact, some experts believe that, of the two parameters, the intensity is most important for cardiovascular benefits. But this raises the question.
How do you know how hard you’re working? Fortunately, there are straightforward ways you can estimate how hard you’re working and with these methods, you don’t need special equipment. Let’s look at three non-techy ways to measure exercise intensity.
Exercise Intensity: Check Your Heart Rate
When you increase the intensity of a workout, your heart has to beat harder to deliver more blood and oxygen to the hard-working muscles. Therefore, heart rate offers a good estimate of how hard you’re exercising.
A heart rate monitor will give you continuous feedback on your heart rate, but it’s not necessary. You can also check your pulse periodically during exercise to estimate your level of intensity. To do this, place your hand on your pulse. Measure your heart rate for 10 seconds and multiply by 6. This will give you your current heart rate.
To estimate exercise intensity from your heart rate, you must first know your maximum heart rate. To determine your maximum heart rate, you can use the following formula:
Maximum heart rate = 211 – (0.64) x age.
The formula has been revised several times based on the belief that the original formula underestimated the maximal heart rate in some populations. Even this formula probably isn’t 100% accurate, but it will give you a rough estimate. The only way to know your maximum heart rate with accuracy is to get a treadmill test.
How do you use the formula? Check your heart rate during exercise and compare it to your maximal heart rate. If you’re working out at a high intensity, your measured heart rate should be in a range of 70% to 85% of your maximum heart rate. For moderate-intensity exercise, 50% to 70%, and for low-intensity exercise 40% to 50% of maximum heart rate.
When you first start working out, it’s best to keep your heart rate at the low end of each range. Shoot for the higher end of the range once you’ve built up a baseline level of fitness.
Exercise Intensity: The Talk Test
Tracking or measuring your heart rate is a reliable way of monitoring exercise intensity, but you might not have a heart rate monitor or relish the idea of stopping to check your heart rate. Well, there’s an even simpler method. It’s called the talk test.
It may be low tech, but studies confirm that the talk test is a viable way to measure exercise intensity and one that requires no equipment. The talk test is based on the concept of the ventilatory threshold. As you increase the intensity at which you exercise, you reach a point where lactate starts to accumulate. This is called the lactate or anaerobic threshold. To compensate for the increase in lactate and to bring your blood pH down, you must breathe at a rapid rate. This point is called the ventilatory threshold, and you can use it to estimate how hard you’re exercising.
Scientists actually measure two markers of ventilatory threshold called VT1, or the first ventilatory threshold, and VT2, the second threshold. VT1 is where you’re just beginning to breathe harder. This is the point where it becomes harder to talk in complete sentences. You can say a few words, but speaking in complete sentences is challenging.
Suppose you push yourself a little harder? Once you reach VT2, the second ventilatory threshold, lactate is rapidly accumulating and your breathing rate becomes even faster. At this point, you’re breathing at such a fast rate that you can’t speak. This corresponds to the lactate threshold.
Exercise Intensity: Level of Perceived Exertion
Finally, you can use the perceived exertion scale to estimate how intensely you’re exercising. The Perceived Exertion Scale is based on a level between one and ten, level one being the lowest in intensity and level ten is maxing out. As you might expect, few people can actually reach level ten. If they do, they can’t sustain it for long. Studies show we’re pretty accurate at using this scale to estimate how hard we’re working. Here’s what the scale looks like:
· 0 – Almost no activity
· 0.5 – Minimal movement
· 1 – Very light activity
· 2 – Light
· 3 – Moderate
· 4 – Somewhat heavy
· 5 – Heavy activity
· 6
· 7 – Very heavy
· 8
· 9
· 10 – Very, very heavy
(from Cleveland Clinic)
Levels 1 and 2 correspond to light activity, like leisurely walking around your exercise. When you’re exercising below level 3, you’re not getting significant cardiovascular benefits.
At levels 2 and 3, you’re working at a low intensity. This level of exertion might correspond to a light warm-up or a leisurely outdoor walk. At this intensity, breathing comes easy and naturally, and you could maintain this intensity for hours.
At levels 4 and 5, your breathing picks up a bit, but you can still carry on a short conversation. This is the level at which many people walk briskly, jog, or cycle for long periods of time.
At levels 6 and 7, your breathing starts to become labored. You can still speak in complete sentences but can’t carry on a sustained conversation.
At levels 8 and 9, you lose the ability to speak in complete sentences and can only get out a word or two at a time. This is the level people strive for during high-intensity interval training, but it’s a level you can maintain for only a short period.
Level 10 is where you max out and are unable to even eke out a few words. Chances are, you won’t get to this level!
The Bottom Line
Now, you know three low-tech ways to determine how hard you’re exercising. Check your level of exertion using one of these techniques every 15 minutes or so. It’ll give you a better idea of how hard you’re pushing yourself. Which method will you choose?
References:
· J Strength Cond Res. 2015 Apr;29(4):894-8. doi: 10.1519/JSC.0000000000000711.
· J Sports Sci Med. 2013 Sep; 12(3): 610–611.
· ACE Fitness. “Validating the Talk Test as a Measure of Exercise Intensity”
Related Articles By Cathe:
Exercise Intensity: How Good Are You at Judging How Hard You’re Exercising?
How Do You Know if You’re Working Out Hard Enough?
4 Benefits of Wearing a Heart Rate Monitor During Exercise
Using Maximal Heart Rate to Measure Exercise Intensity – Is the Formula Flawed?
Endurance Exercise Adaptations: 6 Things That Exercise Increases
How the Heart Rate Response to Exercise Changes With Age
How Accurate Is Maximum Heart Rate for Measuring Exercise Intensity?
