Losing weight around your midsection is not easy. You can do a thousand Crunches a day and not see much improvement.Why? Because you burn calories throughout your body, not just in your abs.

To really get results, you need to incorporate interval training into your workout routine—i.e., alternating bursts of high-intensity exercise with short rest periods. A simple ab routine can burn 200 calories—but an hour of intense interval training can burn up to 1,000.

It doesn’t matter what ab exercise you choose. You could even do Crunches. It’s easy to work an ab exercise into an interval routine. Try doing an ab exercise immediately following each set of Squats or Deadlifts. It will spike your metabolism and burn more calories than strength training alone.

To burn calories at a peak metabolic rate, you want you to keep your heart rate around 80% of capacity. To estimate what your heart rate capacity should be (plus or minus 5 to 10 percentage points), subtract your age from 220.

At that rate, you will burn a lot more calories than with just strength training—and there’s a good chance you will lose more weight.

Want stronger abs? Check out these articles:

• Study Identifies Top 5 Abdominal Exercises
• “Anti-Ab” Training: 4 Effective Unconventional Core Exercises
• A Simple Tool for Six-Pack Success