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.
Bradycardia is a slow or irregular heart rhythm, usually fewer than 60 beats per minute. At this rate, the heart is not able to pump enough oxygen-rich blood to your body during normal activity or exercise. As a result, you may feel dizzy or have chronic lack of energy, shortness of breath, or even fainting spells.