"I believe that every human has a finite number of heartbeats. I don't intend to waste any of mine running around doing exercises"

This quote by Neil Armstrong suggests that he thinks that everyone has a restricted lifespan, and therefore a restricted variety of heartbeats in their life. He expresses his desire to not squander his own heart beats by participating in exercise, indicating that he would rather spend his time doing other things he considers more crucial or enjoyable.