Exercise intensity is one of the most important workout variables, because if the intensity is not correct, your workout won’t have the desired effect. Exercising at the wrong intensity level is one of the most common mistakes people make and it should definitely be avoided, if you hope to achieve optimal results. Intensity might seem like a fairly simple concept, but it is more complicated than it first appears.
The trouble with intensity is it has multiple definitions and different ways of being measured, depending on the type of exercise being performed. For instance, when designing resistance training workouts (e.g. lifting weights), intensity is measured differently than when designing a traditional aerobic workout (e.g. running). Therefore, if you want to design workouts to achieve specific goals, it is important to understand how intensity is used in each situation.
Exercise intensity is a measure of difficulty, but a workout can be very challenging without being considered a high intensity workout. For example, when training with weights or other types of resistance involving sets and reps of various exercises, intensity is determined by the amount of weight used during the set, not the perceived difficulty of the set.
More specifically, intensity is measured as the percentage of your one rep max (1RM). Each exercise has its own 1RM, which represents the amount of weight you can lift one time with proper form. If the greatest amount of weight you can lift during the bench press bench press one time is 100 pounds and you want to train at 80% intensity, then you would use 80 pounds during your bench press sets.
Using a high percentage of your 1RM means you are training at a high intensity and vice versa. This means that performing one rep at 90% of your 1RM is technically considered a higher intensity than performing 5 reps at 85% of your 1RM, although 5 reps at 85% is more difficult. Factors like reps, sets, tempo, and rest periods are not considered when determining the intensity level in resistance training, although they certainly affect the difficulty of the exercises.
Traditional aerobic training (swimming, running, etc.) also uses percentages to signify the level of exercise intensity, but the percentages represent something completely different. With aerobic training, intensity is expressed as a percentage of your maximal heart rate, which reflects the cardiovascular demand of the exercise. In other words, the higher your heart rate, the higher the intensity of the exercise.
Since higher heart rates correspond to higher levels of difficulty, the intensity of aerobic training workouts are more reflective of overall difficulty than the intensity level in resistance training. If you want to design an aerobic workout of a specific difficulty level, all you really need to do is exercise at the intensity (heart rate) that corresponds with your fitness goals.
Even though resistance training and aerobic training measure intensity in different ways, they both use a specific physiological attribute to measure intensity. Resistance training uses muscular strength to quantify intensity and aerobic training uses heart rate. The important thing to note is both types of exercise use a measure that can be numerically quantified, so specific adjustments can be made to improve the effectiveness of each exercise or workout.
When most people refer to intensity, they mean to the general feeling of difficulty, as opposed to a specific physiological measurement. Describing intensity as the overall feeling of difficulty is also a generally accepted definition of intensity. If you have general goals, such as making any type of improvement in your fitness level, then using the general feeling of difficulty as your guide can be appropriate.
However, if you have more specific goals, such as improving aerobic endurance, speed, muscular strength, etc., then your workouts need to be designed to match the intensity level required to stimulate each specific improvement. There is no single workout that improves every aspect of fitness simultaneously, so you have to decide which fitness attributes are most important to you.
Multiple fitness attributes can be improved in a training program, but the more varied the goals, the more different types of workouts are required. For example, training to improve aerobic endurance requires a drastically different workout than training for maximal strength.
Understanding the different meanings and measures of intensity really comes into play when creating workouts to improve specific aspects of fitness. For instance, if you train using weights and want to improve maximal strength and local muscular endurance, you need to train using different intensity levels (use different amounts of weight) for each task.
Training to improve maximal strength requires training with a high intensity (high percentage of 1RM), but you will not be able to perform many reps with the high amount of weight. When training for muscular endurance, you must perform a high numbers of reps, so a lower intensity weight must be used to achieve the desired result. It is important to note that while different intensities are used, the different workouts may feel equally challenging.
If you want your workouts to produce specific physical improvements, it is important to quantify the intensity of your workouts. Using the numerical intensities discussed in this article will help you plan workouts for your specific goals. Plus, keeping track of exercise intensity enables you to chart your progress and make changes to your exercise program as it needs to be modified over time.
On the other hand, if you go into workouts just wanting to exercise at a certain level or feeling of difficulty, then you won’t have nearly as much control over your specific results. Of course, the first thing to do is make sure you know exactly what you want from your workouts and the more specific the better. Then you can make a plan to achieve your desired results instead of simply hoping for the best.