exercising below your target heart rate will

Exercising below your target heart rate may mean that you are not working out intensely enough to get the most benefit from your exercise, particularly if your goal is to improve cardiovascular fitness or to lose weight. The target heart rate is a percentage range based on your maximum heart rate (MHR), which decreases with age. It is generally recommended to exercise within 50% to 85% of your maximum heart rate to ensure you are working out effectively and safely.

If you exercise below your target heart rate zone, you might still gain some health benefits, such as better mood and some level of cardiovascular maintenance, but these benefits might be less pronounced than if you exercised within or above the target zone. It's also important to note that the target heart rate zone is not a strict boundary; fitness benefits can occur outside of this range, though this range is a guideline for optimal cardiovascular benefit.