What is the expected effect on heart rate during hypothermia?

During hypothermia, the body experiences a drop in core temperature, which can significantly affect the cardiovascular system. As body temperature decreases, the metabolic activity slows down, including the electrical conduction system of the heart. This leads to a decrease in heart rate.

Specifically, hypothermia affects the Sinoatrial (SA) node, which is responsible for initiating the heartbeat. The lower temperature results in a slower depolarization rate of cardiac pacemaker cells, ultimately leading to bradycardia, or a slower than normal heart rate. Hence, a decrease in heart rate is expected during hypothermia. Understanding the physiological impact of temperature on heart function is essential in recognizing how the body responds to extreme conditions.