The Effects of Sauna and Cold Immersion on Cardiac Output

a) What is the immediate effect in increasing the peripheral resistance on the cardiac output from the left side of the heart?

a) Decrease

b) What mechanisms in the heart make up for the changes that occurred in part a?

b) Increase in heart rate and force of contraction

Answer:

Increasing peripheral resistance causes a decrease in cardiac output from the left side of the heart, but compensatory mechanisms in the heart help maintain an adequate cardiac output.

The immediate effect of increasing peripheral resistance on cardiac output from the left side of the heart is a decrease in cardiac output. This decrease occurs because the higher peripheral resistance obstructs the flow of blood from the left side of the heart to the rest of the body, resulting in a reduction in the amount of blood pumped out with each heartbeat.

To compensate for this reduction in cardiac output, the heart implements several mechanisms. One of these mechanisms involves an increase in heart rate. When peripheral resistance rises, the heart rate is heightened in an attempt to sustain a sufficient cardiac output. Furthermore, the heart may also enhance the force of contraction to counteract the decreased blood flow.