What effect does inspiration-activated sympathetic activity have on heart rate?

What effect does inspiration-activated sympathetic activity have on heart rate?

• A. It decreases the heart rate
• B. It has no effect
• C. It temporarily increases the heart rate
• D. It stabilizes the heart rate

Answer: (C)

Inspiration-activated sympathetic activity temporarily increases the heart rate due to the physiological response of the body during inhalation. When a person inhales, there is a reflex activation of the sympathetic nervous system that comes into play, leading to an increase in heart rate. This phenomenon is a part of the body's mechanism to ensure that more oxygen is circulated and delivered to the tissues during the respiratory phase when oxygen demand is higher.

The increase in heart rate during inspiration is also associated with the respiratory sinus arrhythmia, a natural variation that occurs in heart rate with the phases of the breathing cycle. As you breathe in, the heart rate rises; conversely, when you exhale, the heart rate typically slows down. This dynamic helps optimize oxygen transport and adapts the cardiovascular response during different phases of the respiratory cycle.