Have you ever started a workout program only to stop after a month or two of not seeing results? If so, don't beat yourself up. Once your heart rate reaches a certain threshold, a metabolic switch in your body gets flipped from aerobic (fat-burning cardio) to anaerobic (muscle-building cardio). Likewise, if you're below a certain threshold, you're doing little more than warming up your muscles.

Your best training tool is your heart rate. To find it, gently place your index and middle finger on the underside of your wrist and feel for the pulse. Count the number of beats you feel during 10-seconds and multiply by six. This result gives you the number of beats per minute. Choose the training zone below that's right for you and we'll calculate your training goal.

Zone 1: Getting Started
In this zone, your blood oxygen flow improves and your muscles and cardiovascular system start preparing for a harder workout. If you're a beginner, use this zone to get started with a consistent fitness routine. If you're training for an athletic event, use Zone 1 at least once a week to let your body recover. If you're looking to lose weight or improve your cardiovascular fitness, you will need to move beyond Zone 1. Calculate >

Zone 2: Burning Fat
If your goal is weight loss, this zone is ideal for you. It's where your body uses energy to metabolize fat and burn it away. If your heart rate goes above the Zone 2 threshold, you'll start to burn carbohydrates instead of burning fat. Calculate >

Zone 3: Building Muscle
In this zone, your metabolism switches from fat burning to muscle building. When your heart rate is high, it causes lactic acid to accumulate in your muscles, which triggers them to tear down and rebuild even stronger. You will still improve your cardiovascular development in Zone 3, but you're not likely to sustain the activity as long as in Zone 2. To lose weight and gain muscle, try interval training among all three zones. Calculate >

Your training goal for:

Zone 2 is: XX-XX beats per minute
Zone 3 is: XX-XX beats per minute

Your training goal for:

Zone 1 is: XX-XX beats per minute
Zone 3 is: XX-XX beats per minute

Your training goal for:

Zone 1 is: XX-XX beats per minute
Zone 2 is: XX-XX beats per minute