Muscles get stronger with exercise. Your heart is a muscle, so the same rule applies. Just like your other muscles, your heart needs time to recover. It’s recommended to alternate vigorous runs with easier workouts in order for your heart to grow stronger. Resting in between is very important to your heart’s long-term health. Your ideal heart rate while running is different for each person. That’s because it may be influenced by: Age
Fitness level (Runners tend to have a lower resting heart rate than less active people)
Heat and humidity may raise heart rate
Medications may slow your heart rate or raise it depending on what kind
Stress may slow or quicken your rate
Most runners between the ages 20 to 45 will want to stay between 100 and 160 beats per minute (bpm), on average. But that average depends on a number of factors, including your maximum heart rate and current fitness level. You can use the formula below to determine your target heart rate range.