Which of the following is NOT a way the cardiovascular system can increase output during times of need?

The cardiovascular system has several mechanisms to increase output, especially during times of increased demand, such as exercise or stress. These mechanisms include increasing the stroke volume, which is the amount of blood pumped by the heart with each beat, and enhancing the efficiency of the heart muscle, which allows it to pump more effectively with less energy. Physiologic heart enlargement can also play a role, as it refers to a natural adaptation where the heart grows to accommodate the increased workload, allowing for improved cardiac output.

On the other hand, a diaphragmatic hernia is a condition in which there is an abnormal opening in the diaphragm that allows abdominal contents to move into the thoracic cavity, which can impair normal respiratory function. This condition does not contribute to increasing cardiovascular output. In fact, it can create complications that lead to diminished cardiac efficiency and can impair the overall functioning of the cardiovascular system. Thus, it stands apart from the other options, which are directly related to enhancing cardiac performance during increased physical demands.