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 heart is a vital organ that pumps oxygenated blood throughout the body, which is essential to keep the body's cells functioning properly. According to the Mayo Clinic, a normal heartbeat rate is 60 to 100 beats per minute, but there are several factors that can cause the heart to beat faster. (Stockbyte/Stockbyte/Getty Images) The most common reason for an elevated heart rate is physical exertion.