In order to stay within the fat burning zone and get consistent results from different cardio activities, a heart rate watch is highly recommended. A good heart rate watch will track calories burned and allow you to measure your progress consistently between different activities.
You can set alarms on the heart rate watch to let you know when you are no longer in your fat burning zone. You’ll then know when to exert more effort or lay off the gas a little bit.
Without a heart rate watch, you have no idea what your heart rate is without stopping to take your pulse. I highly recommend a heart rate watch – you will be using for all of the WLC programs.
You can choose between a variety of heart rate watches here: Heart Rate Watches.
Read the reviews on the watches at the link above and choose one that fits you and your budget. I personally use a FitBit now. I love a FitBit because it gives you so much. Silent alarms in the morning so you don't wake up your spouse or anyone else with an alarm, calories burned, stairs achieved, etc. They are great.
You don’t have to have one of these watches for this program… but it will help you to make better progress and burn more fat during your workouts. You’ll understand which activities allow you stay in your heart rate zone more often.
You can even set alarms to go off when you go outside your set fat burning zones. Be sure to read about the watch and its capabilities before purchasing.
If you go at a medium pace and work up a good sweat, you should be okay without a heart rate watch. It's always good to know exactly where you are, though. I do recommend a heart rate watch.
You can even wear them throughout the day or during your weight lifting workouts to see how hard you’re working.