FITT Principle

How To Use The FITT Principle

A few weeks ago I wrote an article about getting started with exercise. Now I’d like to get into a little more detail about creating an exercise plan that will work for you. In order to do this, exercise professionals use the FITT principle.

FITT stands for Frequency, Intensity, Time and Type. Frequency is how often you exercise, Intensity is how hard you exercise. Time is how long and Type is the type of exercise you are doing. It sounds simple, but the each of these will be different for every woman. Each aspect is intertwined so it is difficult to speak about each separately.


How often should you exercise? I mentioned in my article about getting started with exercise that you should try to move every day. That doesn’t mean you need to do an intense structured workout every day. Especially when you are starting, moving more will be more important than how much you exercise. How often will depend on the type and the intensity.

As we get older, our bodies take longer to recover from an exercise session. For this reason it is a good idea to space out intense exercise sessions of the same type by 2 days.

When doing cardiovascular or aerobic exercise, 3 to 5 days per week is recommended for improvements. For resistance training, 2 to 3 days per week for each muscle group is recommended. This could be done as 2 to 3 full body sessions or 4 to 6 split (upper body/ lower body) sessions.


How intense should your workout be? How intense your workouts are depends on how often and how long you want to exercise. It also depends on your current fitness level. If you are just starting out, you will benefit from exercise at lower intensities, but as you are looking for improvements, you will want to start increasing the intensity. This applies to both resistance training and to cardiovascular exercise.

For beginners I recommend starting with low to moderate intensity for most of your workouts. After you are comfortable with this, you can add a short higher intensity workout and see how you feel.

How do you measure intensity? The easiest way to measure intensity is by going by how you feel. One common method is to use the Borg or RPE (Rating of Perceived Exertion) scale shown below:

0 Rest
1 Really Easy
2 Easy
3 Moderate
5 Hard
7 Really Hard
10 Maximal effort

For cardiovascular exercise, you can also use a heart rate monitor to monitor your intensity. This can be done by measuring by counting your pulse or by using either a chest strap or wrist based heart rate monitor. You can estimate your maximum heart rate using the formula:
208 – (0.7 x age). For a moderate level of exercise your target heart rate should be 55- 70% of this.

For example if you are 50 years old, your maximum heart rate is around:
208 – (0.7 x 50) = 173
And your target heart rate should be: 95 to 121 beats per minute.

If this feels really easy to you, then you may be able to start increasing some of your workouts to a vigorous level.

For strength training intensity is measured by how much you are lifting, how many repetitions and how many sets of each exercise.


How long should you exercise? If you are trying to improve your aerobic fitness then exercising for 20 to 60 minutes in a session is recommended. You can even start with 10 minute sessions and do 2 or 3 sessions per day. A 20 minute session is a good starting point.

You can start to see how frequency, intensity and time are all tied together. You may be able to walk for an hour every day (moderate exercise), but as you increase the intensity to jogging or using a cardio machine, you may only be able to handle 20 minutes at a time. Once your fitness improves you will gain more benefits from a short vigorous exercise session than a long easy session. But long, easy sessions have there place as well. A long walk or hike not only builds endurance, but can improve your state of mind having benefits beyond just the exercise effects on the body.


Choosing the type of exercise can be the hardest part. When you are starting it is best to find an activity that you like or at least don’t hate.

You probably want to stay away from activities that require a skill you don’t have. If you don’t know how to swim, it will be some time before you have the skill to get a good workout from swimming.

Weight bearing activities like walking or jogging are beneficial to bone density, but if you are heavier or have joint pain you may find that non weight bearing activities are easier to start with. Weight bearing activities will also burn more calories than non weight bearing activities at the same perceived intensity.

If you are just starting, you may want to try several activities. This gives you a chance to see which you like the most and also prevents overuse injuries and boredom.

This is a basic guide to using the FITT principle to get the most out of your workouts. If you are looking for more help with your workouts, check out my online personal training programs.


CSEP Physical Activity Training for Health, Canadian Society for Exercise Physiology, 2013

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