There are several synonyms which cardiovascular fitness goes by. It also sometimes referred to as cardiorespiratory fitness, cardiovascular endurance, and aerobic fitness. Cardiorespiratory because, according to Corbin, it would require delivery and utilization of oxygen. This then requires a fit circulatory and respiratory system to do these functions. Cardiovascular endurance is another synonym used because people who possess it can perform physical activity for long periods without undue fatigue. Finally, aerobic fitness because aerobic capacity is considered a good indicator of cardiovascular fitness. 1
What are the benefits of this type of fitness then? We can list these in simple terms, for the time being. (A more detailed and technical discussion can be put forth later.) Among the benefits are:
· Reduces the risk of heart disease, hypokinetic disease, and early death: Studies have shown that people with low fitness have a 70 percent higher death rate from all causes and a 56 percent higher death rate from heart disease than people with intermediate fitness. Low fit people are three to six times more likely to develop metabolic syndrome and diabetes the people who possess high fitness levels. The specific amount of fitness to reduce such risks varies by population and condition, there is evidence that at least moderate fitness levels are required.1
· Good fitness provides protection against health risks associated with obesity: Even people who are overweight and fat can develop cardiovascular fitness with appropriate physical activity. This helps reduce the health risk of being overweight and obese. The other side of the coin is that those who are overweight and obese that have poor cardiovascular fitness have increased health risks. Those who have higher levels of activity, and/or higher levels of fitness, have been shown to possess lower levels of abdominal fat. Individuals can be of the same size, but the more active individuals tend to have lower levels of abdominal fat.1
· Good cardiovascular fitness enhances the ability to perform various tasks, improves one’s ability to function and one’s feeling of well-being: The increase in fitness to reduce disease risk is obvious. Achieving good fitness helps older adults’ ability to function. Among other things, good fitness allows one to enjoy leisure activities and meet emergency situations.1
When beginning a cardiovascular conditioning/fitness program, how do you gauge the intensity of the exercise? While the idea of getting the couch and participating in physical activity is already a big step, one also has to be able to know when the physical activity enough to elicit a response towards fitness improvement. In this case, we talk about cardiovascular physical activity.
One of the easiest ways to do it is to use the RPE (Ratings of Perceived Exertion). This is especially useful if one could not obtain or compute the age predicted maximal hear rate of the individual. The Borg Scale is the most common RPE scale in use and there are two kinds Borg Scales, the 20-point scale and the Category Ratio / CR10 Scale.
|Fig.1 Borg Scale|
|Fig. 2 Category Ratio Scale|
Figure 1 shows the 20-point Borg Scale. It’s use is quite simple. As the client does the cardio exercise, he/she rates the difficulty of the exercise on the scale to the trainer. This is extremely useful if the client is on a treadmill, stationary bike, or cross trainer. All the trainer has to do is show the scale (hopefully printed on a card and large enough to read even when moving) to the client and ask to rate the difficulty of the exercise.
Another test one could use to monitor exercise exertion is the talk test3. While breathing rate will increase during any form of physical activity, moderate intensity activity should allow you to speak comfortably. During vigorous physical activity, talk is limited to short phrases. When the trainer talks to the client, how he/she responds may determine the difficulty of the exercise.
Calculating heart rate intensities is a common method used in monitoring cardiovascular exercise intensity. There are two formulas used for this method. Historically, the oldest and most popular formula used is for calculating a percentage of maximum heart rate, HRmax. Formula is shown below:
After calculating the HRmax, the difference is then multiplied by the desired factor, typically anywhere between 57% to 91% 7. This would depend upon the exercise level of the individual. This approximates light to hard intensity on the RPE scale. Let us apply the formula to a 40-year-old male.
HRmax = 220 – 40
HRmax = 180 bpm (beats per min)
The HRmax is then multiplied by a lower limit percentage, called the threshold heart rate (THR), and higher percentage termed the upper limit heart rate UPHR 1. In this case, the 57% and the 91% mentioned above:
THR = 180 X 57% = 102.6 or 103 bpm
UPHR = 180 x 91% = 163.8 or 164 bpm
When applied to the exercise, the minimum heart rate to be achieved should be at least 103 and the maximum at 164. Ideally the client should stay in that range. However, this formula has considerable variability. It underestimates the HRmax for both genders younger than the age of 40, and overestimates it for both genders over the age of 407. In addition, there is considerable variability at given age with the formula having a standard deviation (SD) of 10-12 beats per minute 4.
A variation of the above-mentioned formula is the Heart Rate Reserve method (HRR). Formula is below:
HRR: Target HR = [(HRmax – HRrest) X %intensity desired] + HRrest
HRmax = maximum heart rateHRrest = resting heart rate
The suggested intensity range for the HRR method ranges from 30% to 80%. This would again depend on the exercise level of the individual. Again, applying the formula to the above-mentioned 40-year-old male, this time adding his resting heart rate, which is at 65 bpm. The desired intensity is, for example, between 50% and 85%.
HRmax = 220 – 40
HRmax = 180
HRR: Target HR = [(180 – 65) X 50% to 80%] + 65
Target HR (50%) = 122.5 or 123 bpm
Upper limit Target HR (85%) = 162.75 or 163 bpm
Therefore, in this case the client’s heart rate should be between 123 and 163 bpm, ± 10 to 12 bpm, during the exercise.
Lately, the ACSM has put forth a new formula for calculating HRmax, which is supposed to be more accurate:
HRmax = 206.9 – (0.67 X age) 7
The HRmax from this new equation can also be used for in the HRR method mentioned above.
|ACSM Suggested HRR-Max Hr Intensity Scale1|
|Habitual Physcial Activity/||HRR/VO2R||
Perception of Effort
|Sedentary/no habitual activity/||30% to 45%||57% to 67%||Light - Moderate|
|Minimal Physical Activity/||40% to 50%||64% to 74%||Light - Moderate|
|Sporadic physical activity/no||55% to 70%||74% to 84%||Moderate - Hard|
|or suboptimal exercise/|
|moderately to mildly deconditioned|
|Habitual physical activity/regular||65% to 80%||80% to 91%||Moderate - Hard|
|moderate to vigorous intensity|
|High amounts of habitual||70% to 85%||84% to 94%||Somewhat hard - Hard|
|activity/regular vigorous intensity|
One should monitor hear rate during exercise. If running or biking outdoors, a hear rate monitor is very useful. Popular brands are Polar and Suunto. Consider investing on one. If no heart rate monitor is available, palpate the radial pulse at the base of the thumb for six seconds, then multiplying the pulse count by 10 seconds. This will give an approximate heart rate for one minute. Do not use the thumb to palpate the radial artery as it has it’s own pulse. Use the second the third fingers. If using a stationary bike, treadmill, or cross/elliptical trainer, these usually have a built in heart rate monitor. It is usually activated by holding onto built in sensors of the machine.
|Using a Heart Rate Monitor|
|Palpating the Radial Pulse|
In designing a cardiovascular exercise program, or any exercise program for that matter, it should follow the FITT principle 3,6,7 mentioned above. For cardiovascular programming, the suggested ACSM FITT 7 program is listed below:
· Frequency: This means how often should the exercise session be. For cardiovascular exercise, the ACSM suggests 3 to 5 days per week depending upon the fitness level of the individual. The more deconditioned, the less the days to start with, gradually building up to 5 days a week.
· Intensity: How difficult is the exercise session. For cardiovascular exercise, this is based on the RPE scale or heart rate calculations presented earlier in this article. The difficulty would, again, depend on the initial conditioning of the client or person. The more deconditioned the person is, the lower the intensity to start with, and again, gradually building up the intensity. However, for persons with special needs, intensity is often substituted for time.
· Time: This is the duration of the exercise session. The ACSM suggests a minimum of 20 to 30 minutes per day, a minimum of 150 minutes per week, of aerobic exercise. If continuous exercise is not possible, several intermittent exercise bouts of 10 minutes are suggested, totalling 30 minutes per day.
· Type: The type of exercise suggested is one that uses large muscle groups. So, running, cycling, swimming are suggested. Use of treadmills, cross trainers, and stationary bikes are recommended also, if available. The trainer, if there is one, should also ask the preference of the client.
A single exercise training session should always contain the following phases: 7
· Warm-up: about 5 to 10 minutes of low to moderate intensity exercises designed to raise body temperature and allows the body to adjust to the physiologic demands placed on it during exercise
· Stretching: This is distinct from the warm-up and cool-down. It may be performed after the warm-up phase or the cool down phase
· Conditioning phase: This is the exercise proper where the aerobic or resistance training occurs and follows the FITT principle (Frequency, Intensity, Time, and Type 3,6,7)
· Cool down: Ideally, this phase contains low to moderate intensity aerobic activity for about 5 to 10 minutes. This is to allow the HR (heart rate) to gradually recover and to aid in removal of metabolic by-products.
1. Corbin, Charles B., William R. Corbin, Gregory J. Welk, and Karen A. Welk “Concepts of Fitness and Wellness 9th edition” 2011
2. Earle, Roger and Thomas Baechle “Essentials of Personal Training” 2004
3. Fahey, Thomas D., Paul M. Insel, and Walton T. Roth “Fit and Well: Core Concepts and Labs in Physical Fitness and Wellness 9th edition” 2011
4. Franklin, Barry A., Senior Editor “ACSM’s Guidelines for Exercise Testing and Prescription 6th edition”, 2000
5. Heyward, Vivian H. “Advanced Fitness Assessment and Exercise Prescription 4th edition” 2002
6. Hoeger, Werner W. K. and Sharon A. Hoeger “Lifetime Physical Fitness and Wellness 11th edition” 2011
7. Thompson Walter R., Senior Editor “ACSM’s Guidelines for Exercise Testing and Prescription 8th edition” 2010