Why Exercise Intensity Is Important

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Exercise intensity is just one of the important components of your workout program, part of the F.I.T.T. Principle, a set of guidelines that shows you exactly how to set up a workout routine. Measuring your workout intensity and using that information to plan your future workouts can help you reach your fitness goals.

What Is Exercise Intensity?

Intensity is probably the most important element of your workout because when you work out at a sufficient intensity, your body grows stronger and you'll see changes in your weight, body fat percentage, endurance, and strength. Exercise intensity is usually measured as low, moderate, or vigorous.

Examples of Low Intensity Exercise

Low intensity exercise raises keeps your heart rate steady and has you moving slowly.

Examples of low intensity exercises include:

  • Walking slowly
  • Riding a bike
  • Lifting light weights
  • Slowly walking on an elliptical machine

Examples of Moderate Intensity Exercise

A moderate intensity workout will raise your heart rate, leave you sweating, breathing heavier, and moving at a quicker pace. You may not be able to talk easily, and you will be feeling warmer.

Examples of moderate intensity exercises include:

  • Hiking
  • Brisk walking
  • Biking
  • Water aerobics

Examples of Vigorous Intensity Exercise

Vigorous intensity exercise will get your heart pumping, elevate your heart rate, and leave you breathing hard. When working out at more intense levels, you will likely not be able to talk for long stretches without needing to take a breath.

Examples of vigorous intensity exercises include:

  • Running
  • Swimming
  • Jumping rope
  • Cycling faster than 10 miles per hour

Benefits of Moderate and Vigorous Intensity Exercise

Increasing the intensity of your workouts can have many benefits, and elevating your workouts can lead to added health improvements.

  • Improves mood. Recent studies have shown that increasing the intensity of a physical activity can have a positive impact on mood and lowering symptoms of depression.
  • Increases calorie burn and metabolic rate. An earlier study examined 10 male subjects and found that 45-minute vigorous exercise resulted in higher calorie burn and a post-workout energy expenditure that lasted for 14 hours.
  • Lower mortality risk. A 2019 research review examined how vigorous and moderate exercise affected mortality risk and found that higher intensity workouts, in particular, lowered the risk of death.

How Hard Should You Work?

How hard you work out during any fitness session and the associated exercise intensity depends on a variety of factors. Your current fitness level, any physical limitation, and your fitness goals all contribute to how hard your workout is.

The CDC notes that adults should have both aerobic and muscle strengthening workouts every week to improve their health. The CDC also recommends adults do 150 minutes of exercise per week (or 30 minutes every day for five days).

Important Safety Precautions

If you begin to feel dizzy, nauseous, are experiencing any pain, have severe trouble breathing, or have sudden cramps, stop your workout. Rest momentarily and if your symptoms do not subside, contact a medical professional.

How to Measure Exercise Intensity

Intensity is also something you want to monitor on a regular basis to make sure you're getting an effective workout. Unfortunately, it's also one of the harder elements to monitor. We have lots of choices, but none of them are perfect, so it often takes a combination of them to really get a sense of how hard you're working. Here are some good ways to track intensity.

Heart Rate

Using a percentage of your maximum heart rate (MHR) is probably the most widely used methods of tracking intensity because it's simple and you can easily monitor your heart rate by using a heart rate monitor.

For this method you use a formula, like the Karvonen Formula to get your target heart rate zone—the heart rate zone you try to work within to get the most effective workout.

The drawbacks here are that the formulas used to calculate THR aren't even close to perfect and can be off by as much as 12 beats per minute. Still, it does give you a place to start.

Heart rate monitors and fitness trackers that detect your heart rate use it as the basis for displaying your exercise intensity.

Talk Test

This is a very easy test to figure out your intensity. You just pay attention to how breathless you are. If you can easily talk, you're working at a light intensity, which is fine for a warm-up. If you can talk, but it's a little harder, you're getting more into the moderate zone. If you can only speak in short sentences, that's right about where you want to be for your workouts.

If you're doing high-intensity interval training, that may include some breathless or anaerobic intervals where talking is out of the question.

Perceived Exertion

Your rating of perceived exertion (RPE), refers to how hard an exercise feels. The standard scale that you will often see is the Borg Scale of Perceived Exertion, which ranges from 0-20.

You could also use a 1-10 scale, which is a little less confusing. The idea is to check in and ask yourself how hard you're working. If you're very comfortable, maybe you're at a Level 3 or 4. If you feel like you're exercising, but are still just in your comfort zone, you may be at a Level 5. If you're sweating and very breathless, you might be at a Level 8 or 9.

Frequently Asked Questions

How can you increase the intensity of exercise?

Increase the intensity of your workout by boosting your running speed, increasing the weight you're lifting, or cycling faster, swimming quicker, and hiking with added speed or weight.

Where do muscles get their energy during high intensity exercise?

For quick bursts of energy, your muscles will pull from adenosine triphosphate (ATP) stores. Carbohydrates are most often converted into ATP for moderate and high intensity workouts.

How do you monitor exercise intensity?

You can monitor your exercise intensity by using any of the three main test methods: measuring your heart rate, doing the talk test, or checking your rating of perceived exertion.

A Word From Verywell

Exercise intensity is just one important aspect of fitness. Importantly, understanding the benefits and how to measure intensity can help you get the most out of your workout and achieve your fitness goals more efficiently.

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Article Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Heart Association Recommendations for Physical Activity in Adults and Kids. American Heart Association. Updated April 18, 2018.

  2. Noh J-W, Lee SA, Choi HJ, Hong JH, Kim MH, Kwon YD. Relationship between the intensity of physical activity and depressive symptoms among Korean adults: analysis of Korea Health Panel data. J Phys Ther Sci. 2015;27(4):1233-1237. doi:10.1589/jpts.27.1233.

  3. Knab AM, Shanely RA, Corbin KD, Jin F, Sha W, Nieman DC. A 45-minute vigorous exercise bout increases metabolic rate for 14 hours. Med Sci Sports Exerc. 2011;43(9):1643-1648. doi:10.1249/MSS.0b013e3182118891.

  4. Rey Lopez JP, Gebel K, Chia D, Stamatakis E. Associations of vigorous physical activity with all-cause, cardiovascular and cancer mortality among 64 913 adults. BMJ Open Sport Exerc Med. 2019;5(1). doi:10.1136/bmjsem-2019-000596.

  5. CDC. Move more; sit less. Centers for Disease Control and Prevention.

Additional Reading
  • American Council on Exercise. ACE Personal Trainer Manual, 5th Edition. San Diego: American Council on Exercise, 2014.