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Running Intensity: How to Measure & Use During Training

Running intensity. The term itself is relatively straightforward, yet most runners would be surprised to learn that that are not utilizing the correct amount of intensity in their training.

Whether they’re stuck in a moderate intensity running rut or simply aren’t including enough variety, training and improvements eventually begin to stall.

What is running intensity?

Running intensity refers to the level of effort and power that is used during a run. It does not always correspond with speed, and is relative to each individual runner. A high intensity run for one might mean running at a 10 minute/mile pace, while it might mean a 5 minute/mile pace for another.

In general, higher intensity runs are completed at a faster speed than lower intensity training – although certain factors such as stress, injury, or previous training with affect the speed as well.

How do you increase intensity in a run?

Most runners tune in to running intensity in hopes that they can increase theirs. It is quite common, especially in long distance training, to get stuck running only moderate or low intensity training.

One successful way to increase running intensity is actually to run slower during easy runs. Running at a low intensity during recovery runs or long runs helps the body conserve energy to really give its all during a high intensity run.

Another way to increase running intensity is to learn your heart rate zones and really monitor your training. Plan one run each week to get your heart rate into the upper zones, and learn what that effort feels like.

Regardless of your plan, the first step is always to learn how to measure different intensity levels, and what the effort and speed feels like in each of those zones.

High Intensity Running vs. Low Intensity Running

Low intensity training is common when preparing for a long distance race, but regardless of your overall mileage, including high intensity running on a regular basis has many benefits.

When every run has a purpose, you’ll find that each runs targets different physiological systems. Every run builds strength, endurance, or power in a way that will improve your overall performance on race day.

High intensity running typically involves intervals, sprints, tempo runs and threshold runs. On the other hand, long runs, easy runs and recovery runs are typically completed at a low intensity level.

The key to differentiating between low and high running intensity involves listening to your body, understanding your heart rate, and identifying your level of exertion. While speed may be an indicator of intensity, it can vary greatly depending on outside factors, making it less reliable.

Understanding running intensity can help increase speed and endurance. Here's how to measure running intensity and how it's used in training.

How to Measure Running Intensity

There are a few different ways to measure running intensity, and some of them are more reliable than others.

Pace or Speed

One of the easiest ways to gauge your running intensity is to simply observe your pace. In general, a higher intensity results in a faster pace.

However, this method can be a bit unreliable as pace can vary greatly due to outside factors. The weather, time of day, your health, stress levels, hydration and more might cause you to run faster or slower than the same effort on a different day.

Running by Feel

Listening to your body and running based on feel can be a surprisingly accurate way to determine running intensity – as long as you do so correctly.

When listening to your body, be careful to do so openly and honestly. Trust that you are running with the same intensity if you are putting forth the same level of effort, even if the pace is slightly different.

Heart Rate

Heart rate is perhaps the most reliable method for judging running intensity. In order to accurately utilize the different heart rate zones, you’ll first want to spend a week or so measuring your heart rate to get a baseline.

Once you understand your resting heart rate and maximum heart rate, you’ll be able to determine your heart rate zones. Runs in heart rate zone 1-3 are generally considered low intensity, while high intensity running lands in zones 4 and 5.

Learn more: The 5 Running Heart Rate Zones

Lactate Threshold or FTP

Another way to measure your running intensity is to take a deep dive into your running stats. If you use a smart watch with a heart rate monitor, you’ll likely find that it has been keeping record of your stats for some time.

Most running watches now record heart rate, and even take things a step further by amazing your lactate threshold and power. Lactate threshold is the level of intensity at which lactate begins to accumulate in the blood faster than the body can remove it.

FTP, or functional threshold power, is the highest possible effort you can sustain for 45 to 60 minutes. This information can be incredibly helpful when it comes to measuring the upper limits of your running intensity.

How Running Intensity Is Used in Training

While the technical terms and advanced measurements may be helpful for really understanding the limits of your running intensity, they are often not actively used during training. Rather, most training plans include terms that describe the type of runs, and let the runner plan speed according to their own body.

Here are some ways running intensity can be used in your training.


A recovery run or interval during training usually involves to the lowest level of running intensity. These runs are typically completed in heart zones 1 or 2, at a very slow pace or walking.


Easy runs, sometimes also referred to aerobic runs, consist of moderate intensity. This is the effort used during most long runs and easy runs or recovery intervals during the week. The pace is still quite slow (significantly slower than the goal pace), and keeps runners in heart rate zones 2 – 3.


A threshold run usually means that a runner should run at the highest intensity possible to maintain for the given amount of time. This is where knowing your lactate threshold or FTP might come in handy. However, if you are unsure, you’ll want to stick around heart rate zone 4 for this run.


A tempo run involves higher intensity than easy runs, but is not quite as intense as a threshold run. Tempo runs typically involve running longer distances than threshold runs at the highest possible running intensity that can be sustained.

Since the length of the run is usually longer than a threshold run, the intensity will have to be slightly lower in order to be maintained.

Interval/VO2 Max

Intervals are usually short and involve some of the highest running intensity possible. Since they are not long, runners are able to max out their intensity, or give it their all during intervals. VO2 Max is a helpful to measure during this time to determine whether your body is getting more efficient at higher intensities.

Related: VO2 Max Charts


Finally, strides and/or sprints are incredibly short, high intensity efforts. These efforts often last only seconds, and give runners a chance to really try to max out their intensity.

Understanding running intensity and how it can be used or varied in your training will set you up for maximum success on race day. Incorporating a variety of runs at different intensities builds strength, endurance and stamina.

Paying attention to your intensity will help avoid getting stuck in a moderate intensity rut, and also avoid running too fast all the time. Finding the best balance for your own body will provide optimal recovery time while still increasing speed and strength each week.

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