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.
About tachycardia, the fast beat. Tachycardia is a rapid heart rate that is faster than 100 beats per minute, and it causes the heart to work too hard. This means that the heart does not have enough time to fill and that not enough blood is being pumped forward. This results in symptoms including palpitations, chest pain, dizziness and fainting.