8.6: Blood Flow in Muscles

Muscle cells depend on the circulatory system to supply oxygen, nutrients, and other needed materials and to remove wastes. Service of muscle cells diminishes somewhat even when no disease of the circulatory system is present. Exactly how much of this decrease is due to age changes and how much is due to a reduction in exercise is not known.

Reasons for the reduced ability of the circulatory system to meet the needs of muscle cells include the decrease in the density of capillaries among muscle cells and age changes in capillary structure. These changes may contribute to the decline in the maximum rate of working and the faster onset of muscle fatigue as people advance in age. These and other age changes in and diseases of the circulatory system that can affect the muscle system were discussed in Chapter 4. (Suggestion 180.01.02)

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