ELLSWORTH AIR FORCE BASE, S.D. -- Airman Kaitlin Walker, 28th Bomb Wing radio and television broadcaster, checks her pulse after a three-minute cardio drill during a fitness assessment, March 9. Airman Walker checked her pulse in order to track her resting heart rate after a cardio workouts. (U.S. Air Force photo/Airman 1st Class Anthony Sanchelli)