You must be at least 17 years old to donate to the general blood supply, or 16 years old with parental/guardian consent, if allowed by state law. Learn more about the reasons for a lower age limit.
Other Causes of Elevated Heart Rate. Elevated heart rate when sick is actually your heartâs aid in order to quell the sickness. However, there can be other causes for elevated heart rate as well. Electrical signals produced and sent to the heart tissues are responsible for controlling the heart rate.
The body must work harder than normal when we are sick in order to fight infection, especially with fevers (when it's battling higher body temperatures, too). To do this effectively, it needs to maintain higher energy levels (which can be tough when it's already working so hard).