Final answer:
The maximum heart rate is the highest number of times your heart can beat in one minute. It usually ranges from 200-220 bpm and decreases as you age. During exercise, the heart rate can increase significantly, resulting in a higher cardiac output. Monitoring the heart rate within the target heart rate range is important to maintain optimal cardiac output.
Step-by-step explanation:
The maximum heart rate (HR) is the highest number of times your heart can beat in one minute. It is an important measure in the cardiovascular system. Maximum HRs usually range from 200-220 beats per minute (bpm), but it may vary depending on individual factors such as age. As you age, your maximum HR decreases. A rough estimation can be made by subtracting your age from the maximal value of 220 bpm. For example, a 40-year-old individual would have a maximum HR of approximately 180 bpm, while a 60-year-old person's maximum HR would be around 160 bpm.
During exercise, the heart rate can increase significantly. In healthy young individuals, HR may reach up to 150 bpm. This increase in HR is accompanied by an increase in stroke volume (SV), the amount of blood pumped by the heart in each beat. This results in a higher cardiac output (CO), the total amount of blood pumped by the heart per minute. The CO during exercise can be 4-5 times higher than the resting rate. Elite cardiovascular athletes can achieve even higher levels, increasing resting CO by 7-8 times.
It's important to note that there is a correlation between heart rate and cardiac output. Initially, as HR increases, the SV also increases, leading to a higher CO. However, as the HR continues to rise, the filling time for the ventricles decreases, causing the SV to gradually decrease. At very high HRs, CO may eventually decrease as the increasing rates are no longer able to compensate for the decreasing SV. It is recommended to monitor the heart rate during exercise to ensure it stays within the target heart rate range of 120 to 160 bpm to maintain an optimal CO.