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
Where:
HRmax
= maximum heart rate
HRrest = 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 | %HR Max |
Perception of Effort |
||||||
| Exercise Level | |||||||||
| Sedentary/no habitual activity/ | 30% to 45% | 57% to 67% | Light - Moderate | ||||||
| extremely deconditioned | |||||||||
| Minimal Physical Activity/ | 40% to 50% | 64% to 74% | Light - Moderate | ||||||
| no exercise/moderately- | |||||||||
| highly deconditioned | |||||||||
| 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 | |||||||||
| exercise | |||||||||
| High amounts of habitual | 70% to 85% | 84% to 94% | Somewhat hard - Hard | ||||||
| activity/regular vigorous intensity | |||||||||
| exercise | |||||||||
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.
Bibliography:
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
