Dear Doctors: I'm a 55- year-old man, and I have been active all my life. I know target heart rates are based on age and was surprised that my heart rate while running is often between 150 and 195.

As you age, many aspects of your body shift, including your heart’s response to physical activity. One of the most important changes is how your heart rate behaves during exercise. Your maximum and ...

I'm a 55-year-old man, and I have been active all my life. I know target heart rates are based on age and was surprised that ...