In the last article, we looked at the benefits of maintaining good cardiovascular fitness.
In this column, we examine how using the FIT formula can improve the development of cardiovascular fitness.
Initially, it is important to note that adaptation to physical activity depends on two principles of fitness – overload and progression.
To build fitness, you must load or challenge your cardiovascular system by doing more than you normally would. But the challenge or overload should also be progressive, increasing gradually as your fitness improves.
For people with low physical fitness, moderate physical activity is all that is necessary to create an increase in the load. For people with higher levels of physical fitness, vigorous physical activity will be essential for improvement.
The acronym FIT stands for frequency (F), intensity (I), and time (T) for exercise.
To build cardiovascular fitness, the exercise frequency should be three to five or more days per week. Most experts agree that at least one rest day per week to allow recovery is beneficial.
The intensity of the physical activity necessary to produce cardiovascular fitness depends on a person’s fitness level. Physically fit people need to exercise at a higher intensity to provide an adequate challenge to the cardiovascular system.
In general, heart rate provides a good indicator of the relative challenge a given bout of exercise. Thus, guidelines for physical activity intensity to build cardiovascular fitness are based on a percentage of heart rate reserve.
To calculate the heart rate reserve, use the following formula:
Calculation of maximum heart rate (for 22 years old)
Maximum heart rate
= 208 – (.7 x age)
= 208 – (.7 x 22)
= 208 – 15.4
193 bpm
Heart rate reserve calculation (for a 22-year-old with a resting heart rate of 68 bpm)
Maximum heart rate – 193 beats per minute
Minus resting heart rate – – 68 beats per minute
Heart rate reserve equals 125 bpm
Target heart rate zone for intensity setting is 65 to 80%
Thus, to determine the minimum heart rate for building cardiovascular fitness, we use 65% of the heart rate reserve added to the heart at rest (−65 × 125) + 68 = 149 bpm.
The upper limit of the target area is (.80 x 125) + 68 = 168 bpm. Thus, a person’s target heart rate zone is between 149 and 168 beats per minute (BPM).
Because target zone heart rates differ for people with different fitness levels and because resting heart rates vary, the minimum and maximum levels for each person will be unique to them.
If you are wondering how to calculate your resting heart rate, just find the radial pulse at your wrist and calculate it for a minute.
The exercise time usually depends on the minutes of activity per day. National guidelines require at least 150 minutes of moderate activity per week or 75 minutes of vigorous activity (or a combination of the two).
For example, a person of moderate fitness might do five 30-minute exercises each week to reach their goal. So in this example, a person who wants to build cardiovascular endurance does so five days a week, at an exercise intensity of 149-168 bpm, for 30 minutes.
This is FIT’s principle in action.
