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 45kg 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 60kg, 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.2 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 10,3 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).
Written by Paul Rogers from www.verywellfit.com