If you want to hit your fat-burning zone, you have to exercise for a longer period of time. Your body uses mostly glycogen stores during the early stages of exercise, and uses more fat stores the longer you work out.
If youâ€™re really trying to burn fat and lose weight, aim for an hour of low- or moderate-intensity exercise. Why not high-intensity? Because the harder you work out, the less time youâ€™ll be able to keep doing it. Intensity and endurance are inversely related. When one goes up, the other needs to go down â€“ until you get in shape. So, for fat burning, keep the endurance up and the intensity down.
Experts recommend working out at 70% of your heart rate max, which is considered to be the optimal intensity level for improving aerobic endurance. To calculate your fat-burning zone, subtract your age from 220 to find your maximal heart rate. Then, multiply this by 70% to find your ideal heart rate intensity.
For example, a 35-year-old person would have a heart rate max of 185 beats per minute (bpm) and their ideal intensity for reaching their fat-burning zone would be about 130 bpm.
You can monitor your heart rate by using a heart rate monitor or checking your heart rate manually during exercise. Staying within this zone will allow you to exercise longer and burn more overall calories in the long run.