One of the key metrics in tracking your workouts is intensity. And yet, as runners, we don’t often hear “intensity” talked about. We talk about time and distance, and we talk about pace, intervals, and hills. From reading about training plans, we know that varying the difficulty of our workouts from day to day is an important part of making progress. Even if we know that this all relates to intensity, many of us don’t know how to measure intensity.
Knowing how to measure your workouts by intensity will help you gain far better understanding of your fitness journey.
So in this article we’ll discuss why you should measure exercise intensity and how to do it, both with and without a heart rate monitor.
Whether you’re happy with your fitness routine, or have started running to pick things up, measuring intensity will help you get the most out of your exercising.
What is Exercise Intensity?
Exercise intensity simply means how hard you are working out or exercising. It’s typically used to refer to aerobic activity like running or walking. The harder you exercise, the more of a benefit you’ll see to your physical fitness and cardiovascular system.
There are two ways to measure exercise intensity. The first is by feel. This is answering the question: how challenging a particular activity feels to you. If running today feels harder than running yesterday, then your exercise intensity is higher today.
Another way to determine exercise intensity is by heart rate. This gives you a more accurate picture of how hard your body is working. While people who exercise a lot tend to know their bodies well and have a good idea of exercise intensity, using heart rate initially can help beginners.
Why Should I Measure Exercise Intensity?
Knowing how hard you’re working out can help you in a variety of ways. First, if you’re supposed to do an easy run at a particular pace according to your training program, and it always feels really hard, then maybe you need to adjust your training plan.
Similarly, it can help you schedule your workouts. It’s a bad idea to go hard every day. Your body needs time to recover and rebuild in order to make progress. That’s what easy days are for. Too much high-intensity work and you’re going to injure yourself. Knowing how many harder workouts you’ve done in a week will help you keep a balanced exercise regime.
Finally, maybe you’re following the guidelines that experts suggest, like 150 minutes of moderate aerobic activity per week or 75 minutes of vigorous aerobic activity. Knowing what category your exercise fits into will help you in meeting these goals.
What Are Two Ways to Measure Exercise Intensity?
As we mentioned above, you can measure exercise intensity simply by feel. This is more subjective, but you can get really good at it.
You can also measure by heart rate. This provides hard, objective data. But you have to know how to read that data, and what to do with it. That’s less objective than many people would like to think. There’s both science and art involved in interpreting heart rates, heart rate zones, and effort.
The first way to measure exercise intensity is by feel. You should ask yourself questions like the following:
- Does it feel easy, moderate, or hard?
- Can I hold a conversation?
- How hard am I breathing?
- How much am I sweating?
While the first question is somewhat subjective, you know your body better than anyone else. Could you keep up this activity for forever, or are you ready to stop?
The talk test, or determining if you can hold a conversation, is a great way to gauge intensity. For example, if you can sing, then it’s probably too easy for you.
If you’re able to talk and say the Pledge of Allegiance, then it’s moderate. If you can only say a few words, then it’s vigorous.
Finally, tracking your breathing and sweating is a good determination of the intensity of an exercise.
If you can barely breathe and are sweating like a pig, then your intensity level is vigorous. If you have to keep track of your breathing and are sweating some, then it’s moderate.
By Heart Rate
In order to calculate exercise intensity based on your heart rate, you’re going to have to do more work than just ask yourself some questions.
You first have to figure out your target heart rate. Then, measure your heart rate during an activity to determine your exercise intensity.
How Can I Measure My Heart Rate?
A GPS watch with a heart rate monitor is the easiest way to measure heart rate. Don’t have one? Don’t worry. You don’t have to purchase a new device in order to do this.
Athletes had hearts and heart rates long before there were heart rate monitors. You can track your effort easily the old-fashioned way by taking your heart rate manually. While you’re exercising, take a break and find your pulse either on your neck or your wrist. Count the number of beats in 10 seconds, and multiply that number by 6.
If you want to do less math, you can take your pulse for 15 seconds and then multiply that number by 4. Let’s say that you count 25 beats in 10 seconds. Multiply 25 by 6 and you get 150 beats per minute, which you can use to find your exercise intensity.
Heart Rate Monitor
If you don’t want to do math at all and would prefer a monitor, you can use either a chest strap or wrist heart rate monitor. The chest strap HRM is more accurate, but can be uncomfortable. The wrist HRM is less accurate but comfortable and convenient.
Nowadays, most GPS watches and fitness trackers come with heart rate monitors, so there’s no extra gear to buy or connect. It’s easy to figure out what your heart rate during an exercise is without having to stop.
How Can I Use Heart Rate to Determine Intensity?
In order to determine intensity, you have to calculate your target heart rate zones. You do this by figuring out your max heart rate. The most common way to do this is by subtracting your age from 220. For example, 220-28 = 192, the estimated max heart rate for a 28-year-old.
This method should be seen as a very rough approximation. That being said, it’s close enough for the vast majority of recreational runners. If you are serious enough to want a more accurate number, you might want to try an intensity test instead. You can run for three minutes as hard as you can, rest for three minutes, and then run hard for three minutes again. Your max heart rate is the highest number from the second run. Of course, this test is only as good as your ability and willingness to truly max your body out.
Once you know your max heart rate, you can figure out your heart rate zones. Zone 1 is 50-60% of your max heart rate—this is for recovery. Zone 2 (60-70%) is manageable, while Zone 3 (70-80%) is picking up the pace. Finally, Zone 4 (80-90%) and Zone 5 (90-100%) is when you’re starting to get close to or even are going all-out.
How Can I Use Heart Rate Zones While Exercising?
Once you know these heart rate zones for you personally, you can use them for training. If you’re trying to get in 150 minutes of moderate activity per week, then you’ll want to make sure that your heart rate is in Zone 2 during your exercise.
If you want to increase your cardiovascular fitness and burn more calories, you can start incorporating intervals based on heart rate and include short stints of 15-60 second Zone 3 or 4 exercise with periods of Zone 1 or 2 recovery.
This is where things get a little grey. For example, one popular method of training is called “Heart Rate Training,” or HRT. In this approach, you strictly limit your heart rate to easy efforts. But that means different things in different training programs. By the standard age calculation of 220 – age, HRT must workouts stay in Zone 2. Otherwise, they aren’t considered easy.
Another popular HRT approach, the Maffetone method, doesn’t start with your maximum heart rate, but with an ideal aerobic heart rate, which is found by subtracting your age from 180, and then making some other adjustments based on training history or injuries. The basic result is that an “easy” run in this method is done at a somewhat higher heart rate than the previous method.
We all know that exercise—as with most things in life—requires balance. Knowing your exercise intensity will help you maintain that balance. Making sure that your easy days are just that—easy—and your hard workouts are challenging will help you make the most of your exercise.
Remember: exercise is very personal, so it’s important to know the details for you. What is high intensity for you might be low intensity for someone else. Make sure you know what’s best for you individually.