A Level Biology Practice Exam

What physiological condition might result in increased oxygen uptake in the lungs?

1. Exposure to cold environments

2. Engagement in high-intensity exercise

3. Becoming dehydrated

4. Sitting for extended periods

The correct answer is: Engagement in high-intensity exercise

Increased oxygen uptake in the lungs is closely associated with the body's demand for oxygen, particularly during situations where energy expenditure is heightened. Engaging in high-intensity exercise requires a significant amount of energy, which in turn necessitates a greater supply of oxygen to fuel metabolic processes. As physical activity increases, the body's muscles require more oxygen to sustain aerobic respiration, leading to an upsurge in the rate of breathing (ventilation) and, consequently, an increase in oxygen uptake in the lungs. During such activities, physiological adaptations occur, including an increase in heart rate and deeper breaths, to maximize the amount of oxygen transported to the working muscles. This process allows the body to perform optimally under stress and maintain homeostasis. Therefore, high-intensity exercise is a well-recognized condition that effectively illustrates the body's acute response to increased metabolic demands for oxygen.