When working out, your heart rate should generally be between 50% and 85% of your maximum heart rate. The maximum heart rate is roughly calculated as 220 minus your age. Staying within this target heart rate zone helps ensure you are exercising at a moderate to high intensity that benefits cardiovascular fitness without overexerting yourself. Here are some key points for target heart rates during workouts:

• Moderate intensity exercise corresponds to about 50% to 70% of your maximum heart rate.
• Vigorous intensity exercise corresponds to about 70% to 85% of your maximum heart rate.
• For example, if you are 30 years old, your estimated maximum heart rate is 190 beats per minute (bpm). Your target heart rate zone for moderate exercise would be about 95 to 133 bpm, and for vigorous exercise about 133 to 161 bpm.
• Starting with the lower end of your target zone and gradually increasing intensity is a good approach.
• Using the "talk test" can help gauge intensity: being able to talk but not sing means moderate intensity; only managing a few words without catching your breath signals vigorous intensity.

Following these guidelines helps improve heart health, endurance, and overall fitness safely and effectively.