Return to Main Page

Cardiorespiratory Fitness

As mentioned last week, there are five basic components to fitness. One of these is cardiorespirtory fitness. This involves the ability of the body to supply oxygen and blood to the body.

---

Cardiorespiratory (CR) fitness, sometimes called CR endurance, aerobic fitness, or aerobic capacity, is a condition in which the body's cardiovascular (circulatory) and respiratory systems function together, especially during exercise or work, to ensure that adequate oxygen is supplied to the working muscles to produce energy. CR fitness is needed for prolonged, rhythmic use of the body's large muscle groups. A high level of CR fitness permits continuous physical activity without a decline in performance and allows for rapid recovery following fatiguing physical activity.

Activities such as running, road marching, bicycling, swimming, cross-country skiing, rowing, stair climbing, and jumping rope place an extra demand on the cardiovascular and respiratory systems. During exercise, these systems attempt to supply oxygen to the working muscles. Most of this oxygen is used to produce energy for muscular contraction. Any activity that continuously uses large muscle groups for 20 minutes or longer taxes these systems. Because of this, a wide variety of training methods is used to improve cardiorespiratory endurance.

---

FITT Factors

A person must integrate several factors into any successful fitness training program to improve his or her fitness level. These factors are summarized by the following words which form the acronym FITT. Frequency, Intensity, Time, and Type. They are described below as they pertain to cardiorespiratory fitness. A warm-up and cool-down should also be part of each workout.

FREQUENCY
Frequency refers to how often one exercises. It is related to the intensity and duration of the exercise session. Conditioning the CR system can best be accomplished by three adequately intense workouts per week; do these on alternate days. By building up gradually, you can get even greater benefits from working out five to seven times a week. However, recognize the need for recovery between hard exercise periods and adjust your training intensity so you don't have two intense workouts back-to-back. Adding workouts to improve the three other fitness components (flexibility, muscle strength and muscle endurance) should be incorporated to ensure overall fitness.

INTENSITY
Intensity is related to how hard one exercises. It represents the degree of effort with which one trains and is probably the single most important factor for improving performance.
Changes in CR fitness are directly related to how hard an aerobic exercise is performed. The more energy expended per unit of time, the greater the intensity of the exercise. Significant changes in CR fitness are brought about by sustaining training heart rates in the range of 60 to 90 percent of maximum heart rate. Intensities of less than 60 percent are generally inadequate to produce a training effect, and those that exceed 90 percent can be dangerous.

A good training tool, especially in CR or aerobic training, is monitoring your heart rate during exercise.
Info on how best to monitor your heart rate are described below.

---

What factors affect aerobic training?

As mentioned above: Frequency, intensity, time (duration), and type - FITT.
Frequency refers to how often you perform aerobic activity.
Intensity refers to the percentage of your maximum heartrate or heartate reserve at which you work.
Time refers to the duration spent at each session.
Type refers to the method of exercise.
Only aerobic exercises that require breathing in large volumes of air improve CR fitness. Worthwhile aerobic activities must involve the use of large muscle groups and must be rhythmic. They must also be of sufficient duration and intensity (60 to 90 percent of max HR). Examples of primary and secondary exercises for improving CR fitness are as follows:

PRIMARY

• Running.
• Rowing.
• Jogging.
• Skiing (cross-country).
• Walking (vigorous).
• Exercising to music.
• Rope skipping.
• Racewalking.
• Bicycling.
• Swimming.
• Stair climbing.

  SECONDARY

  • Racquetball.
  • Basketball (full court).
  • Handball (singles).
  • Tennis (singles).

  The primary exercises are more effective than the secondary exercises in producing positive changes in CR fitness.
  The secondary activities may briefly elevate the heart rate but may not keep it elevated to at 60 to 90 percent of max HR throughout the entire workout.

  ---

  MEASURING YOUR HEART RATE

  As your fitness improves, your heart rate at rest decreases. It works less at rest as you get more fit.
  Elite athletes who train nearly full time will have resting heart rates in the 50 to 60 beats per minute (bpm) range.
  Typical students who may exercise a bit will have resting heart rates in the 70 to 80 bpm range.

  Heart rate is widely accepted as a good method for measuring intensity during running, swimming, cycling and other aerobic activities. Exercise that doesn't raise your heart rate to a certain level and keep it there for 20 minutes won't contribute significantly to cardiovascular fitness.

  The heart rate you should maintain to improve CR fitness is called your Target Heart Rate and it is generally considered to be 60 to 90 % of your maximum heart rate.
  There are several ways of arriving at this figure. One of the simplest is to first determine your maximum rate based on your age.
  Use the following formulas:
  Men: 220 minus your age
  Example: If your age is 20
  220 - 20 = 200 beats per minute (bpm)
  Women: 226 minus your age
  Example: If your age is 20
  226 - 20 = 206 beats per minute
  Step two:
  To find your zone, take this maximum HR and multiply it by 0.60 and 0.90 to get the 60% and 90% range.
  For example: If your maximum rate, based on age, is 200 bpm, multiply this in this manner:
  200 X 0.60 = 120
  200 X 0.90 = 180
  Your training rate (also the rate we use for MODERATE exercise in this course) is 120 to 180 bpm.

  Resting heart rate should be determined by taking your pulse after sitting quietly for five minutes.
  When checking heart rate during a workout, take your pulse within five seconds after interrupting exercise because it starts to go down once you stop moving. Count pulse for 10 seconds and multiply by six to get the per-minute rate.

  A general guideline for determining intensity level is illustrated in the chart below:
  
  

  
  Your target heart rate zone, as illustrated on the chart, would include the weight management, aerobic and anaerobic threshold zones. This is 60 to 90 percentiles.

  Going to the higher intensities periodically will improve what is called anaerobic threshold and can lead to overall CR fitness improvements.
  The trouble with going to the higher intensities is that most people can't maintain that level for very long.
  Reducing intensity to increase duration is important for CR fitness as well.
  Having a workout plan that incorporates longer but slow sessions, as well as faster but shorter sessions, is a good way to go.
  
  

  Return to Top of Page

  Return to Main Page