How Do You Measure Exercise Intensity?

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As runners, we love to get wrapped up in the fancy workout data – pace, heart rate, elevation, VO2 – that we sometimes forget simpler ways to measure our runs.

Exercise intensity—how hard you’re working during your activity—is one of those metrics that many of us runners are guilty of neglecting. Maybe it’s because it’s harder to quantify than other bits of data.

But once you start training according to exercise intensity, you can better gauge how well you are running both at the moment and when you are done.

So, how do you measure exercise intensity? Read on to find out exactly what it is, the optimal intensity to train, and how to do it right.

What Is Exercise Intensity?

Simply put, your exercise intensity is the amount of energy you’re expending when you run. Or – put another way – the amount of effort you’re putting into your workout.

Exercise intensity has a direct link to how much strength you gain, how much weight you lose, and how much your cardiovascular system improves.

This is why you can “exercise” every single day without fail, but if you’re taking a leisurely stroll around the block without breaking a sweat, you’re not going to see a whole lot of improvement in your fitness.

There are three levels of intensity: low, moderate, and vigorous or high. For reference, the American Heart Association recommends 150 minutes of moderate-intensity exercise per week or 75 minutes of high-intensity exercise—but a combination of the two will be most effective.

Low Intensity

Low-intensity exercise raises your heart slightly and keeps it stable in that raised state. It’s generally slow-paced and easy. Some examples include:

  • A leisurely walk
  • An easy bike ride
  • Light weightlifting
  • Any cardio machine at a slow pace

Moderate Intensity

Moderate-intensity exercise will boost your heart rate more noticeably. You’ll likely breathe heavier, sweat a little, and move faster than your normal pace.

These exercises are a step up from low intensity by increasing the speed or resistance. Some examples could include:

  • Hiking
  • Walking briskly
  • Mountain biking
  • Cycling at 10 mph or less
  • Slightly heavier weightlifting

Vigorous Intensity

Vigorous intensity exercise gets your heart pumping hard, as well as your breathing. You’ll most likely not be able to speak much, it won’t take long for you to start sweating, and you’ll fatigue much more quickly. Some examples include:

  • A hard run
  • Sprint intervals
  • Cycling at >10 mph
  • Jumping rope
  • Rowing hard

Why Is It Important to Measure Exercise Intensity?

Your gives you a lot of data, right? So why is exercise intensity important?

Ultimately, it’s up to you to make changes and adjustments to your exercise and life to maximize the data and the results.

Here’s why learning how to measure exercise intensity can benefit you in the long run.

Mind/Muscle Connection

One of the best things about being mindful of your exercise intensity is that it teaches you to be more aware of your own body, your mind-muscle connection, and what your body is telling you.

You’d be surprised at how much difference this can make to keeping you injury-free and boosting your performance!

To Make Sure You’re Getting Enough Exercise

Figuring out which of your exercises are high-intensity and which is low- or moderate-intensity helps you to hit those all-important numbers of 150 or 75 minutes per week.

This isn’t just for performance, either. These are the numbers recommended for general health, so it’s valuable to know if you’re hitting them or not.

To Get the Most Benefit from Your Workout

The intensity level of your exercise can either get you closer to or further from your goals. For example, high-intensity exercise is great for losing weight, but only if you do it right and don’t go overboard.

Moderate-intensity exercise is super for building cardiovascular endurance. Once you know what intensity you’re working at and how to change your activity to hit a particular intensity, you can cater to your goals much more specifically.

Helps to Avoid Injury

If you’re constantly going all out, you’re on track to overtraining. Tracking your exercise intensity will help you monitor your workouts and adjust them to avoid burnout.

You can actively structure your workouts so that you don’t end up overdoing it and injuring yourself.

Can Help You to Track Progress

The longer you’re aware of your intensity, the more you’ll start to notice how exercise that used to be difficult for you is becoming easier and easier. Intensity is one of the best ways to compare previous performances and see real progress!

That 10-mile run that you struggled to complete in the beginning? It’s a great feeling when you realize you’re no longer huffing and puffing at the end! It’s a tangible and pleasing way to see your progress and stay motivated!

How to Measure Your Exercise Intensity

Now you know that exercise intensity is an important metric, how do you measure it? There are a few different ways, all of which have their pros and cons.

Rate of Perceived Exertion (RPE)

Borg’s Rate of Perceived Exertion Scale is a scale from 6 to 20 that helps you figure out how much effort you’re putting into an exercise. Most runners use a more simplified scale of one to 10, which is easier to figure out.

It goes quite a bit by feel, but it’s an excellent way to get more in touch with your body. Walking to the fridge and back counts as a 1 on the scale—your everyday activity.

Moderate activity comes in at a 4 to 6 level. At this point, your breathing will be a little heavier, and you’ll be able to have short conversations.

Vigorous activity is a 7 to 8 on the scale. In other words, 70 to 80 percent of your maximum effort. At this level, you’ll be getting uncomfortable, breathing hard, and struggling to speak for more than a sentence or two at a time.

We recommend using this scale regularly to check in on how you’re feeling during any given exercise. It’s also a great way for new runners to start gauging effort, especially if you have no experience yet with training by heart rate.

Try the Talk Test

The talk test is a simple way of figuring out your intensity without having to do complicated mathematics. Just try to hold a conversation while you’re doing your activity. Here’s a quick guide:

  • Easy talking: Light intensity
  • Short bursts of talking between breaths: Moderate intensity
  • Only a few words & short of breath: Vigorous intensity

Heart Rate-Based Metrics

If you wear a smartwatch or use a heart rate monitor, your heart rate is an excellent way to gauge intensity during a run or other workout. The first step to use heart rate successfully is to calculate your maximum heart rate.

  • 220 – (your age) = your max heart rate

So, as an example, if you’re 30 years old, your maximum heart rate should be 190. This isn’t exact, but it’s close enough for most people. From there, you’ll need to do a little more math to find out your target heart rate zones.

  • Moderate exercise: 40 to 60 percent of your maximum HR.
  • b 70 to 80 percent of your maximum HR.

If you’re still building up your fitness, aim for the lower end of the spectrum. For example, try to keep your heart rate at around 40 percent for moderate exercise, and 70 percent for vigorous activity.

As you build up fitness, your heart rate will improve, which means you can up the intensity a little while still staying in the same zone. This is how you build your fitness!

A More Accurate Calculation for Vigorous Activity

You can calculate your target heart rate zones just using the percentages above. But for a more accurate range, here’s how to figure out where you should be keeping your heart rate during vigorous activity.

  1. Calculate your resting heart rate first thing in the morning.
  2. Calculate your maximum heart rate.
  3. Subtract your resting HR from your max HR.
  4. This is known as your heart rate reserve, or HRR.
  5. Multiply your HRR by 0.7 and add your resting HR.
  6. This becomes your lower target HR.
  7. Multiply your HRR by 0.85 and add your resting HR.
  8. This becomes your upper HR limit.

For example, here’s how a 40-year-old with a resting HR of 65 would calculate this.

  • Resting HR: 65
  • Max HR: 180
  • HRR: 115 (180 – 65)
  • Lower HR Target: 145.5 (115 x 0.7, + 65)
  • Upper HR Target: 162.75 (115 x 0.85, + 65)

When doing vigorous exercise, your heart rate should stay between 145 and 163 beats per minute. This is the most accurate way of figuring out intensity using your own body’s data!

Spot-check your heart rate during exercise to make sure you’re still in the right zone. Your smartwatch should be able to tell you at any given point what your HR is, or you can stop and measure your own pulse for 15 seconds, then multiply it by 4 to get your beats per minute.

You can then adjust up or down in intensity, based on where you’re falling in relation to your target heart rate numbers.

How to Monitor Your Heart Rate

We highly recommend focusing on heart rate training rather than just using perceived effort.

But how can you measure your heart rate accurately while you’re exercising, to make sure you’re in the right HR zone? There are multiple ways to do so—the one you choose will depend on your personal preference.

Check Your Pulse

Checking your pulse is fairly accurate and can eliminate some of the inaccuracy issues that lower-end smartwatches can sometimes have. However, it may be inconvenient to stop your workout and measure your heart rate.

If you do choose to do it this way, it’s easy, although you should do it every 10 to 15 minutes to make sure you’re still within the right range. Here’s how:

  • Place your first two fingers against the inner wrist of the opposite hand.
  • Press lightly into the small hollow next to the tendon until you can feel the pulse.
  • Use a watch or a timer to count down 15 seconds, and count down many beats you feel within that time.
  • Multiply that by 4 to get your beats per minute.

If you want it to be a bit more accurate, you can measure your pulse for 30 seconds and multiply it by 2, or just count for a full minute. If you struggle to feel your pulse on your wrist, you can use your carotid artery—it’s a little more uncomfortable, but easier to feel.

GPS or Smart Watch

Most runners have a smartwatch, so this is a common way of measuring and tracking your heart rate. Your smartwatch should adjust to your own bodyweight and metrics to give you fairly accurate heart rate zones for your own body.

You should be able to check out your heart rate on the go while you’re exercising, although it’s advisable to keep it on the “always on” setting and not the “every 10 minutes” setting.

You’ll also be able to check yourafter your workout, so you can see how to adjust your intensity next time to hit your targets.

Wear a Chest Strap Heart-Rate Monitor

A chest strap HRM is the most accurate way to measure your HR. You can find them pretty easily online, and they measure accurately thanks to their close proximity to your heart.

It could be hard to check your heart beat on the go, though, because you may have to open the accompanying mobile app to see it. If you’re in the middle of a workout, this might not be convenient.

Heart Rate Monitor Armband

If you don’t like the idea of a chest strap, you can find other types of heart rate monitors that might be more comfortable for you. One of the most accurate versions is a bicep heart rate monitor, which sits against your brachial artery and measures your pulse extremely accurately.

Factors That Can Influence Your Heart Rate

Remember, exercise isn’t the only thing that gets your heart rate up. External factors can also influence your HR, both during exercise and at rest. Keep these in mind when working with your heart rate, and when in doubt, check with a medical professional.

  • Your caffeine intake (more = higher heart rate)
  • The weather (hotter = more effort = elevated HR)
  • Time of day (your circadian rhythm changes your HR)
  • Hormonal fluctuations daily, weekly, and monthly
  • Stress (stress elevates cortisol levels, which increases HR)
  • Cigarette smoking
  • Some medications

How Often Should Runners Do High-Intensity Training?

High-intensity training definitely has its place. Research shows that 2 to 3 HIIT sessions per week is great for endurance runners to boost performance.

If you’re not an endurance runner, you can still do 2 to 3 HIIT sessions a week if you want to. But most people find it more optimal to do one or two, and to stick to moderate and lower-intensity runs for most of their exercise.

Exceeding 3 HIIT sessions per week will put you on a track to overtraining or injury. As tempting as it might be, keep it to one or two if possible—you’ll still see the benefit, just without the negatives!

Signs You’re Overexerting Yourself

Focusing on intensity can be a great motivation to perform better, but it can also cause you to accidentally push yourself too hard. If you find yourself experiencing more than one of these symptoms while running, stop immediately.

If they don’t subside with rest, get yourself to a doctor so you can make sure there’s nothing underlying.

  • Extreme shortness of breath
  • Wheezing or uncontrollable coughing
  • Pressure or pain in the chest or jaw
  • Sweating an unusual amount
  • Dizziness or lightheadedness
  • Muscle cramps or sharp pains
  • Nausea or stomach cramps
  • Sudden, exhausting fatigue

Tips to Measure and Adjust Your Exercise Intensity on the Go

Want to increase or decrease your intensity but not sure how? Here are some easy tips you can incorporate on-the-go to adjust your exercise intensity.

Pay Attention to Your Breathing Rhythm

Keep an eye on your breathing rate. If you’re breathing heavily and irregularly and struggle to have a chat without gasping for more breath, you’re probably at a moderate intensity. If you struggle to get a word out at all, you’re probably going hard.

You can use this as a quick gauge to figure out your intensity at any given point, and you can adjust your effort to lower or increase it as you wish.

Adjust Your Intensity by Varying the Terrain

Not all terrain is just easy to run on. If you’re hitting the sidewalk, it’s fairly predictable and simple to run on, so you should be able to do a light-intensity workout here if you wish to. You can increase your speed to up your intensity on flat ground.

But if you truly want to boost intensity without increasing your speed, pick a more challenging terrain. Hills are an excellent way to add intensity to your run without actually deviating from your regular speed.

Hydration and Fueling

Being dehydrated or under-fueled can negatively impact your perceived effort. In other words, dehydration or lack of muscle glycogen can make you feel like you’re working a whole lot harder than you actually are, because your body is fatiguing faster.

Maintaining your dehydration and fueling yourself properly for your runs can make a huge difference. Suppose you usually run on an empty stomach. In that case, you might want to reconsider—simply fueling yourself before your run can have a significantly positive impact on your perceived effort and your performance.

Count Your Steps Per Minute

In other words, keep an eye on your cadence! Generally, a higher cadence means you’re running more efficiently, and a higher running efficiency means you’re wasting less energy during your movement.

Counting your steps will give you an indication of your cadence. A normal cadence is between 160 and 180 steps per minute. Increasing your cadence can help to reduce your intensity, as your stride will become more efficient and you should be able to increase your speed.

Scan for Signs of Fatigue

If you notice your legs feeling heavy, tightness in your muscles, or loss of coordination, ease up on the intensity. This is a sign that you’re getting close to overexerting or injuring yourself, so keep a close eye out for these kinds of signs.

Use Technology Wisely

You can use your watch to keep checking your pace or heart rate, but that can become tiring and it’s also easy to forget to check when you really get into things. Instead, we recommend using your smartwatch for activity alerts.

Most smartwatches have this feature. You can set it to alert you when your heart rate goes over a particular number, but you can also use cadence of speed as your chosen metric. This makes it easy for you to stick to your target heart rate zone without constantly checking to see how you’re doing.

Mind Your Form

Form makes a big difference to your intensity. If you’re running with bad form, it’ll increase your intensity, because the strain on the wrong parts of your body will make the movement harder.

When you notice your form deteriorating, slow down or take a bit of a break. If you continue with poor form, you’re at a higher risk of injuring yourself.

Listen to Your Body

Your body feels everything and it gives you constant feedback. If something feels wrong, stop or lower your intensity noticeably. Intensity isn’t everything—if you’re struggling to keep your intensity high or even moderate, don’t stress.

Keep working at a lower intensity and as your overall fitness increases, you’ll be able to push that intensity more. Be patient and remember—any exercise is good exercise, as long as your form is on point!

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AUTHOR

Ben is an avid road and trail runner, and has completed multiple marathons and ultras. A former running store owner, he now shares his knowledge and experience writing these articles.