F.I.T.T. Concept

Frequency - How often do you exercise per week? (exercise sessions per week) 
Aerobic activities must be performed at least three times per week to reach an adequate level of cardiovascular fitness. 

Intensity - How hard is your exercise session? (Level of intensity) 
To obtain the greatest cardiovascular benefits, the American College of Sports Medicine recommends that the intensity of your training be sufficient to increase your heart rate to a range of 60% to 90% of your maximum heart rate. This is your target heart rate zone.

To find your target heart rate zone; 220 - (minus your age) x .90 = Upper limit of your target heart rate zone 
220 - (minus your age) x .60 = Lower limit of your target heart rate zone 
 

Time - How long do you exercise? (Duration of the exercise session) 
To achieve all the values of cardiovascular training, you must maintain the target heart rate (60% - 90%) for a minimum of 20 minutes. As you become more fit, you should increase the your time in the target heart rate zone to gain a higher level of fitness. However the intensity level may need to be reduced or lowered, in order for your body to accommodate or handle the stress from the increase in time. 

Type - What type of activity/exercise did you choose; Aerobic (Cardio Respiratory Training) or Strength Training (Resistance Training)