Which of the following is a normal cardiac output at rest?

The normal cardiac output for a resting adult is typically estimated to range between 4 to 6 liters per minute. This value represents the amount of blood the heart pumps in one minute and is crucial for ensuring adequate blood flow to meet the body's metabolic demands. At rest, the body requires a stable and consistent supply of oxygen and nutrients, which is facilitated by this level of cardiac output.

In individuals who are healthy, this range reflects how well the heart is functioning under normal physiological conditions without the stress of physical exertion. While cardiac output can vary based on factors such as age, fitness level, and health status, the typical resting output aligns with the selected range of 4 to 6 liters per minute. Understanding this value is fundamental for assessing cardiovascular health and for making appropriate clinical decisions in geriatric physical therapy.

The other ranges presented would either indicate a low cardiac output, which may signify poor heart function, or an elevated output, which is often associated with heightened physical activity or stress on the cardiovascular system. Therefore, the range of 4 to 6 liters per minute is consistent with physiological norms at rest, making it the correct answer.