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After completing this chapter, you should be able to do the following:

  • Relate the importance of cardiorespiratory endurance to overall fitness and health.

  • Contrast aerobic and anaerobic activity.

  • Explain how maximum aerobic capacity determines your level of cardiorespiratory endurance.

  • Describe the principles of continuous, high-intensity interval, and fartlek training and the potential of each technique for improving cardiorespiratory endurance.

  • Analyze specific aerobic activities that can be used to improve cardiorespiratory endurance.

  • Identify methods for assessment of cardiorespiratory endurance.


  • aerobic activity

  • anaerobic activity

  • stroke volume

  • cardiac output

  • aerobic capacity

  • maximum aerobic capacity

  • fast-twitch muscle fibers

  • slow-twitch muscle fibers

  • FIT principle

  • continuous training

  • target heart rate

  • heart rate reserve

  • Karvonen equation

  • rating of perceived exertion

  • interval training

  • fartlek

Why Is Cardiorespiratory Fitness Important for You?

Of all the components of physical fitness listed in Chapter 1, none is more important than cardiorespiratory endurance, also referred to as cardiovascular endurance. Cardiorespiratory endurance is the ability to perform whole-body activities and continue movement for extended periods without undue fatigue. We rely on the cardiorespiratory system to transport and supply the oxygen needed by the various tissues within our bodies. It is the basic life-support system of the body. Without oxygen, the cells within the human body cannot function, and ultimately death occurs.

Everyone needs some degree of cardiorespiratory endurance to carry out normal daily activities. If you are engaged in any physical activity, the cardiorespiratory system must work harder to deliver enough oxygen to sustain that activity. Thus, as the cardiorespiratory system becomes more efficient at supplying the needed oxygen, your level of cardiorespiratory fitness improves, and you are likely to be more resistant to fatigue (Fig. 4-1).

Figure 4-1

Challenging the cardiorespiratory system. Engaging in exercise forces the cardiorespiratory system to become more efficient at supplying needed oxygen and thus improves fitness. Courtesy of Dirima/iStock/Thinkstock.

For older individuals such as nontraditional college students, the health benefits of improving cardiorespiratory endurance may be more important than the fitness benefits.

Engaging in regular physical activity will also improve your cardiovascular health and can greatly reduce your chance of heart disease. If you have low levels of cardiorespiratory endurance, your risk for developing heart disease is higher than normal.

What Is the Difference Between Aerobic and Anaerobic Activities?

Without oxygen, the body is incapable of producing energy for an extended period of time. Muscles must generate energy to move. Three energy-generating systems function in muscle tissue to produce a chemical compound called adenosine triphosphate (ATP), which is the ultimate usable form of energy for muscular activity. They are the ATP, glycolytic, and oxidative systems. During sudden outbursts of activity in intensive, short-term exercise, ATP can be rapidly metabolized to meet energy ...

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