Where the numbers come from
The percentiles come from the CDC's National Health and Nutrition Examination Survey (NHANES), 1999-2008, published as Resting pulse rate reference data for children, adolescents, and adults: United States, 1999-2008 (National Health Statistics Reports No. 41, 2011). The data excludes people with a medical condition or medication that affects pulse rate.
The CDC groups adults as 16-19, 20-39, 40-59, 60-79 and 80+. Your result is placed within your group by interpolating between the published percentiles.
How to measure
Sit or lie quietly for a few minutes, find your pulse on your wrist or neck, and count the beats for 30 seconds. Double it. Morning readings before you get up are the most consistent.
