Chapter 15: Improving Cardiovascular Endurance

CHAPTER OBJECTIVES

At the completion of this chapter, the reader will be able to:

1. Explain the importance of cardiovascular endurance in the overall health of an individual.

2. Describe the physiology of the cardiovascular system.

3. Describe the various types of energy and how each is generated.

4. Explain how the various muscle types are involved with endurance and aerobic activities.

5. Outline the precautions with aerobic conditioning.

6. Discuss the various methods by which aerobic conditioning can be enhanced through a rehabilitation program.

OVERVIEW

Physical activity has been defined as “any bodily movement produced by the contraction of skeletal muscles that results in a substantial increase in resting energy expenditure.”¹ When a person undertakes work or exercise, several body systems adapt to the demands of the required tasks, particularly the cardiorespiratory and neuromuscular systems. The maximum work capacity of the cardiorespiratory system is a factor of the maximal amount of oxygen that can be taken in and used by the body, or VO₂ max, whereas the capacity of the neuromuscular system is a factor of the maximum tension that the working muscle or muscles can develop—the maximal voluntary contraction. The cardiovascular system assessment allows the clinician to justify monitoring activities during a patient’s rehabilitation or providing modifications in the exercise prescription.²

It is recommended that individuals aged 18–64 years perform at least 150 minutes per week of moderate-intensity aerobic activity, at least 75 minutes per week of vigorous-intensity aerobic activity, or equivalent combinations.³ Physical activity increases cardiorespiratory fitness, and this fitness may be a stronger predictor of mortality than smoking, blood pressure, and other established risk factors.

If our sedentary society is to change to one that is more physically active, clinicians must play their role in communicating the amounts and types of physical activity that are needed to prevent disease and promote health because patients respect their advice. Health professionals should also be physically active to benefit their health and make their endorsement of an active lifestyle more credible. Whenever possible, the clinician should address the negative impact on the patient resulting from the loss of physical activity. This loss of activity affects both the cardiovascular and musculoskeletal systems and can occur very rapidly. Thus, the rehabilitation program must include exercises that maintain, or improve, the patient’s cardiovascular endurance while monitoring safety concerns. Patients should be routinely counseled to adopt and maintain regular physical activity. While policymakers improve reimbursement for preventive services, clinicians should develop effective ways to teach physical activity counseling.