To give blood you must: 1  Be in general good health.  Be at least 17 years old. (If you are 16 you can donate with a CBC consent form signed by your parent). There is no upper age limit as long as you have no health restrictions.
Specific radiative intensity. Specific (radiative) intensity is a quantity used in physics that describes electromagnetic radiation. It is a term used in much of the older scientific literature. The present-day SI term is spectral radiance, which can be expressed in base SI units as W mâ2 srâ1 Hzâ1.
Absolute intensity. The amount of energy used by the body per minute of activity. See Measuring Physical Activity for more. Aerobic physical activity. Activity in which the body's large muscles move in a rhythmic manner for a sustained period of time.Aerobic activity, also called endurance activity, improves cardiorespiratory fitness.Examples include walking, running, and swimming, and bicycling.ctivity in which the body's large muscles move in a rhythmic manner for a sustained period of time. Aerobic activity, also called endurance activity, improves cardiorespiratory fitness. Examples include walking, running, and swimming, and bicycling.