American Board of Surgery Qualifying Exam (ABS QE) Practice Test

Which change is commonly observed in the pulmonary status of aging individuals?

1. Increased strength of respiratory muscles

2. Lower lung volumes by approximately 50% from 30 to 70 years

3. Enhanced cough reflex sensitivity

4. Improved response to low oxygen levels

The correct answer is: Lower lung volumes by approximately 50% from 30 to 70 years

As individuals age, various physiological changes occur within the respiratory system. One significant change is the reduction in lung volumes, particularly the total lung capacity and vital capacity. By the time an individual reaches 70 years of age, it is common to observe lung volumes decrease significantly, often estimated to be around 50% compared to those at 30 years of age. This decline is attributed to several age-related factors, such as loss of elastic recoil in the lungs, decreased mobility of the chest wall, and atrophy of respiratory muscles. These changes ultimately lead to an increased risk of respiratory disorders and can impair overall pulmonary function. In contrast to this, aging is associated with a decline in the strength of respiratory muscles, rather than an increase. The cough reflex can also diminish, leading to reduced sensitivity for eliciting a cough, which is essential for clearing secretions. Additionally, the ability to respond effectively to hypoxia diminishes with age, meaning the body becomes less capable of responding to low oxygen levels. These factors highlight the importance of understanding the normal physiological changes that accompany aging and their implications for respiratory health.