Final answer:
Exercise triggers an increase in sympathetic activity to the heart, leading to an increase in cardiac output. This allows more blood, oxygen, and nutrients to be delivered to the muscles during exercise.
Step-by-step explanation:
Exercise triggers an increase in sympathetic activity to the heart. Sympathetic stimulation causes an increase in heart rate and stroke volume, which leads to an increase in cardiac output. This means that during exercise, more blood is pumped out of the heart, resulting in increased blood flow throughout the body.
For example, when you run, your sympathetic nervous system is activated, causing your heart rate and stroke volume to increase. As a result, more blood is pumped out of your heart with each beat, leading to an increase in cardiac output. This increased cardiac output allows more oxygen and nutrients to be delivered to your muscles, enabling them to perform better during exercise.
Overall, the increase in sympathetic activity to the heart during exercise has a positive effect on cardiac output, helping to meet the increased demand for oxygen and nutrients by the body.