A patient who recently completed a 12 week program of phase III cardiac rehabilitation will MOST likely demonstrate a decrease in:

A patient who recently completed a 12 week program of phase III cardiac rehabilitation will MOST likely demonstrate a decrease in:

• A. CO2 elimination in maximal work
• B. Cardiac output in maximal work
• C. Stroke volume at a given level of submaximal work
• D. Heart rate at a given level of submaximal work

Answer: (D)

Endurance training shifts the heart’s response to submaximal exercise so the same amount of work is achieved with a lower heart rate. After a period of rehabilitation like 12 weeks, the heart becomes more efficient: stroke volume increases due to favorable cardiac adaptations (greater preload from improved venous return, enhanced contractility, and bigger left ventricular filling), and autonomic balance shifts toward more parasympathetic and less sympathetic activity during steady, submaximal effort. Because each beat delivers more blood, the heart doesn’t need to beat as fast to meet the same metabolic demand, so heart rate at a submaximal workload decreases. It’s less likely for max heart rate or max cardiac output to go down with training; maximal measures can stay similar or improve, and stroke volume at submaximal workloads is usually higher, not lower. The key, and the most consistent training effect, is the reduced heart rate for a given submaximal effort.

Endurance training shifts the heart’s response to submaximal exercise so the same amount of work is achieved with a lower heart rate. After a period of rehabilitation like 12 weeks, the heart becomes more efficient: stroke volume increases due to favorable cardiac adaptations (greater preload from improved venous return, enhanced contractility, and bigger left ventricular filling), and autonomic balance shifts toward more parasympathetic and less sympathetic activity during steady, submaximal effort. Because each beat delivers more blood, the heart doesn’t need to beat as fast to meet the same metabolic demand, so heart rate at a submaximal workload decreases.

It’s less likely for max heart rate or max cardiac output to go down with training; maximal measures can stay similar or improve, and stroke volume at submaximal workloads is usually higher, not lower. The key, and the most consistent training effect, is the reduced heart rate for a given submaximal effort.