On your journey to total health, it’s crucial to understand how your heart rate relates to your level of fitness. You may already know that your heart rate is one measure of your workout level. Most cardio machines today offer built-in heart rate monitors, but to help ensure that you’re getting the most benefit from your time at the gym without overtaxing your heart, requires some some understanding on the relationship between your heart rate and your overall health.

1. How Your Baseline Heart Rate Changes Over Time

If you’ve ever heard a baby’s heartbeat during a sonogram, you know that the rate is much faster than an adult’s. Even after birth, a newborn’s resting heartbeat is between 100-150 beats per minute. As humans grow, the maximum attainable heart rate declines with age due to size – not fitness.

2. How to Calculate Your Maximum Heart Rate

The absolute maximum that a young child’s heart can beat – which would be during strenuous activity – is 220 beats per minute. Now you know that with age, that maximum reduces. So to calculate your own maximum heart rate, you would take away your age from 220. If you’re 30 years old, your maximum heart rate is 190.

3. Why You Need to Know Your Maximum Heart Rate

You wouldn’t want to max out your heart muscle with every workout, or for very long periods of time, but you do want to give your heart muscle some exercise. If you constantly push yourself so you’re at maximum heartbeats for your age, your workouts will be brief and exhausting, not to mention potentially dangerous. A good rule of thumb is to aim for around 80 percent of your maximum heart rate, depending on your level of fitness. So if you’re 30 and your maximum heart rate is 190, multiply that by .80 to get your target, healthy maximum heart rate. The answer would be 152 in this example.

To safely workout your body and your heart muscle with this example, you would work up to a rate of 152 beats per minute, maintain that during your peak, and then slow down until you reach your normal resting heart rate. Knowing how your heart rate relates to your level of fitness will keep you healthy, fit and strong.