Health and Diet Online Glossary
Rating of Perceived Exertion (RPE): The level of effort a person feels they are putting into an activity. Lower numbers indicate lower levels of exertion. This is often used as a means to measure performance trends over time.
RDA: Recommended Dietary Allowance. The amount of an essential nutrients or calories that have been established by the Food and Nutrition Board of the National Academy of Sciences, to meet the average daily nutritional needs of most people according to age group and sex. Obviously the caloric or nutritional RDA is different for everyone, but does provide a great reference point.
Resting Heart Rate: or (RHR): A measure of heart beats per minute when the body is completely at rest. Typically the most accurate results can be obtained immediately after waking up in the morning.