You may have heard personal trainers and doctors stressing the importance of heart rate without ever really answering a simple question: Why does it matter? And how should heart rate be measured? Get the details on why measuring your heart rate during exercise is important — and how to effectively use a heart rate monitor — below.

Why Does Heart Rate Matter?
Keeping tabs on your heart rate during workouts allows you to check in on your current health status and helps determine the proper recovery time you need after a workout or set of intervals. Your heart rate will also give you information about the intensity at which you’re working during a particular exercise, which helps to make your workouts more effective.

Measuring your heart rate also prevents you from working too hard (which can lead to injury), and helps monitor weight loss and cholesterol levels. Measuring your heart rate is especially helpful for cardiovascular training like running, biking or swimming. These activities keep your heart rate aerobic (meaning muscle movement uses oxygen to burn fat, produce energy and build your endurance) versus anaerobic (which are short bursts of energy that don’t require oxygen).

Measuring Heart Rate
Measuring your heart rate without a monitor can seem tricky, but it only takes about 30 seconds. Start by placing your index and middle finger on your neck or wrist to take your pulse. Count the number of beats for six seconds then add a zero, or count the number of beats for 30 seconds and double it. Ideal heart rate ranges vary depending on your age and fitness level, but you can use a rudimentary equation of 220 – age = maximum heart rate to create “easy,” “moderate” and “difficult” heart rate zones. For example, the difficult heart rate zone for a 40-year-old person would range between 160-180 beats per minute (bpm), while moderate would be 140-160 bpm and easy would be 120-140 bpm.

How to Use a Heart Rate Monitor
Exercising at the proper intensity level will improve your overall fitness and, as a result, help you get the results you’re looking for. Once you’ve determined your ideal heart rate zones, try interval training (which can be done on a bike, treadmill or elliptical machine) to increase the intensity of your workouts. Using a heart rate monitor throughout these workouts to monitor heart rate will allow you to stay within your target zones during exercise, making your workouts more effective while preventing you from maxing out too early or injuring yourself.

With a wide range of costs and features, there’s a heart rate monitor on the market for nearly every price point and fitness goal. Top-rated brands include:

Keep in mind that your heart rate is just one tool at your disposal to evaluate a workout, and it can be affected by a variety of factors including dehydration, temperature and lack of sleep. Learn to listen to how you feel throughout your workout in addition to keeping tabs on your heart rate.