Nan,age 70,feels more out of breath while exercising.This is probably because
A) the blood flow to her circulatory system has increased.
B) her heart muscle is more responsive to signals from pacemaker cells.
C) her vital capacity has reduced significantly due to aging.
D) her T cells are becoming more effective and efficient.

Question

Quizplus · Accepted Answer

As people age, the vital capacity of the lungs (the maximum amount of air that can be forcefully exhaled after a deep inhalation) tends to decrease. This means that older individuals may find themselves feeling more out of breath during exercise, even if their heart and circulatory system are functioning normally. Option A is incorrect because increased blood flow to the circulatory system during exercise is a normal response and would not necessarily cause shortness of breath. Option B is incorrect because while pacemaker cells do play a role in regulating heart rate, they do not directly affect breathlessness during exercise. Option D is also incorrect because T cells are part of the immune system and not directly involved in respiratory function.

Nan,age 70,feels More Out of Breath While Exercising