You should think of the FITT principle as a list of rules that need to be fulfilled so that you can have progress with any fitness workout you practice.

The FITT rules are:

• Frequency
• Intensity 
• Type
• Time

This are the four fitness rules that you should practice no matter if you’re training on a higher or lower level. Also, they can be used for cardio workout.

FREQUENCY

Through every form of fitness workout, the body goes through a process of renewal and correction to upgrade the energy reserves in the body and are necessary for continuous exercising.

The frequency of exercising is balance between the exposure to stress as much as the body can and giving the body enough time to recover and begin adaptation.

Cardio workout

Cardio - respiratory workout should be done minimum 3 times a week and max 5 times a week. However, don’t go too far, take some rest.

Workout with resistance

The frequency of the training and the program with resistance is different for every individual. For example, a program that covers all body parts should be trained 3 - 4 times a week and rest of 1 day in between.

From the other side, program which is focused on 1 and 2 muscles can be trained even 6 times in a week. Many bodybuilders practice this routine.

Remember that, every time you do a strength workout for any group of muscles, you strengthen your body including the inner organs ( heart, lungs etc.) 

INTENSITY

The second rule at the FITT routine is related to the intensity, or quantity of effort that needs to be invested in the training program.

Like mentioned in the first principal - frequency - balance needs to be found so there will be enough intensity to encumber the body.

Heart rate can be used as a measure of the intensity cardio workout, while resistance training can be used for weights that are used for exercising.

Cardio workout

Heart rate is the primary measure of the intensity aerobic endurance training. Target zone of the heart rate. The zone depends on your fitness level (how much you’re ready) and your years.

Here is a quick method to find your target heart rate.

• Normal and maximal heart rate

The heart rate is measured in beats per minute. Find the pulse on you ankle, hand or neck. Measure for 15 seconds and multiple by 4, and you will have the hear rate per minute. The maximum of the heart rate can be measure with the relation 220 bpm - age = Max heart rate.

• Heart rate zone

For beginners, the zone is 50-70% from the max. For example if you’re 40 years old, the maximum of your heart rate would be 180. Multiply this number with 50% and 70% and you will reach for the zone of 90 bpm - 126 bpm.  

If you are a fit person, your target zone is 70-85%. Your target zone of heart rate as a 40 year old person is 126 bpm - 153 bpm.

Workout with resistance

For workout with resistance, the weights are the only measures of the intensity. They can contain of three components.

1. The weight that is lifted during exercising
2. The number of repetition during different exercises.
3. The time period needed to perform all of the exercises in sets or the whole training.

So, you can increase the weight or you can increase the number of repetitions with the same weight. Or as a last case, you can lift the same weight and do the same number of repetitions with reducing the rest time between sets.

Be careful and increase the intensity of only one of the three components.

TYPE

The third component of the FITT principle is what type of exercises you should choose to achieve an appropriate change as answer for your training.

Cardio workout

The best type of exercises for maintaining or improving your cardio vascular system and condition are exercises where you use the big group of muscles. For example: jogging, walking, swimming, dancing, driving bikes, aerobic etc.

Workout with resistance

The best way to put your neuro system on stress and effort is the workout with resistance. But  workout with resistance doesn’t include weight lifting only. Elastic resistance can be   also used as an alternative (when you go on a trip somewhere)

TIME

The last component of the FITT principle of exercising is the time - how long you should exercise and is it true that the longer means better?

Cardio workout

People who are beginners should try to make sustainable training which will maintain the target zone heart rate of at least 20-30 minutes, while the others need to do it 45-60 minutes.

Above 60 minutes the body will be exhausted and you won’t get the expected results. Also, there is always danger from over training and injuries. Exception are only marathon runners and athletes that train ultra long durability.

The length of the program should be minimum 6 weeks if you want to see good results. If you want to reach for the maximum, the duration needs to be 1 year and more.

Workout with resistance

It’s known that the duration of the workout with resistance should not be longer than 45-60 minutes, while the workout for strength should last 20-30 minutes.

After all - the most important principle during the workout is the rest. Too frequent and exhausting exercising makes the body unable to get well and adjust. The rule is -" The more you train, the more rest you need to take".