Volume vs. Intensity in Weight Training

woman preparing to do a deadlift
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In weight training, volume is the term used to describe how much work you do, such as the number of repetitions (reps) you perform of an exercise. Intensity describes the difficulty of an exercise, typically based on the amount of weight you lift.

Take deadlifts as an example. If you do five reps with a 100-pound barbell and increase to 10 reps with the same barbell, you have increased the volume. If you do five reps but increase the barbell weight to 150 pounds, you have increased the intensity.

How Volume and Intensity Affect Fitness

Volume is key for muscle growth (hypertrophy) as well as muscular endurance. It's one of the best ways to progress and keep seeing results in your hypertrophy goals. While performing many reps with lighter weight is good for endurance, adding additional sets and reps to your current training increases volume and progress. Add more sets or repetitions of different exercises to see further muscle growth.

For muscular endurance, you can use a lighter weight with more repetitions to exhaust the muscle. You can also use this technique to build cardiovascular endurance. For example, in this case of deadlifts, a higher volume forces your heart and lungs to work harder. As you adapt to the changes in volume, your cardiovascular fitness and endurance will improve.

Adding intensity to your training can increase calorie burn and strength goals. For instance, if you take less rest between sets, your heart rate will stay elevated throughout the workout, leading to a greater calorie burn. If you boost intensity by explosively lifting the weights, you can increase strength and power.

Also, increasing the weight of a lift will build your cardiovascular system. Think about lifting something very heavy over and over again. It takes a lot of effort, and effort increases your heart rate.

It's similar to walking up a hill vs. flat ground. Even if you go the same distance (i.e., volume), hill walking is more demanding. So your heart rate will increase much more. The same is true when lifting heavier weights: Your heart rate increases, boosting your cardiovascular endurance.

Measuring Volume and Intensity

Volume can be measured by the hours and minutes you train (such as on a treadmill) or the number of sets and reps you do in a workout. If you do hybrid training, such as circuits or intervals, volume might involve both duration and reps.

By contrast, intensity is measured by either the weight you lift or the pace in which you perform an exercise (such as running). The rate of perceived exertion (RPE) can be used as a general guide to intensity levels. RPE is often measured on a scale of 1 to 10, with 1 for no activity and 10 for maximum exertion. Intensity may also be measured on a Borg scale of 6 to 20.

Measuring Fitness Levels

While muscle mass is relatively easy to measure, your actual fitness level is based on multiple factors, such as how well your heart and lungs respond to intense physical exertion. As a general rule, the intensity of a workout is described as a percentage of your maximum heart rate (MHR). The MHR is the maximum number of heartbeats you experience during one minute of intense effort.

To improve your cardiovascular fitness, you should aim for 65% to 75% of your MHR. At this level, you are improving your aerobic fitness (your body's ability to use oxygen to fuel workouts).

You can estimate your maximum heart rate by subtracting your age from 220. However, if you have a heart condition or are older and haven't exercised in a while, check with your doctor to determine a safe maximum heart rate for you.

For a more accurate assessment, you can take a treadmill stress test under the supervision of doctor or sports physiologist. The same test can also ascertain your VO2 max (the maximum amount of oxygen your body can utilize during intense exercise). Increases in VO2 max indicate increases in lung capacity and endurance.

Ultimately, your heart's response to the intensity and volume of a workout will establish your fitness level. Whatever your baseline MHR, you can improve your overall fitness by increasing the duration and intensity of an activity.

If you are exceptionally fit, you can train to between 80% and 90% of your MHR. This will place you in an anaerobic state in which your body utilizes glycogen stored in your muscles rather than oxygen to fuel exercise.

While in an anaerobic state, you not only improve your heart and lung function, but you also stimulate muscle growth better than aerobic exercise alone. It is this combination of volume (measured by duration) and intensity (measured by pace) that can help you achieve muscle growth and cardiovascular health all at the same time.

4 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. Schoenfeld BJ, Contreras B, Krieger J, et al. Resistance training volume enhances muscle hypertrophy but not strength in trained menMed Sci Sports Exerc. 2019;51(1):94-103. doi:10.1249/MSS.0000000000001764

  2. Hackett DA, Johnson N, Chow C. Respiratory muscle adaptations: a comparison between bodybuilders and endurance athletes. J Sports Med Phys Fitness. 2013;53(2):139-45.

  3. Helms ER, Cronin J, Storey A, Zourdos MC. Application of the repetitions in reserve-based rating of perceived exertion scale for resistance training. Strength Cond J. 2016;38(4):42-49. doi:10.1519/SSC.0000000000000218

  4. American Heart Association. Know your target heart rates for exercising, losing weight and health.

Additional Reading

By Paul Rogers
Paul Rogers is a personal trainer with experience in a wide range of sports, including track, triathlon, marathon, hockey, tennis, and baseball.