What finding would necessitate the termination of low-level exercise for a patient in a cardiac rehabilitation program?

The finding that would necessitate the termination of low-level exercise in a cardiac rehabilitation program is a decrease in systolic blood pressure of 15 mm Hg. This significant drop in systolic blood pressure can be indicative of an inadequate cardiovascular response to the physical demands of exercise, potentially leading to insufficient blood flow to vital organs.

In a cardiac rehabilitation setting, maintaining adequate blood pressure during exercise is crucial. A sudden decrease in systolic blood pressure can signal a risk of adverse events, such as fainting or even cardiovascular complications. Such changes necessitate immediate cessation of exercise to ensure the patient's safety.

The other findings, while they may require monitoring, do not typically necessitate immediate termination of exercise. For example, an increase in diastolic blood pressure of 5 mm Hg can be a normal response to exercise, as can a heart rate of 108 beats per minute, depending on the patient's exercise tolerance and baseline cardiovascular condition. Mild lower extremity claudication does warrant attention and careful management, but it does not automatically indicate that exercise must be stopped; the severity and the individual patient's tolerance and condition play critical roles in the decision to continue exercising.