Long cardio workouts bad for losing fat?

Originally Published: October 31, 2008 - Last Updated / Reviewed On: August 9, 2011
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Dear Alice:

I've recently read from the Internet that long cardio workouts (e.g. running) are not the best for permanent fat loss. These articles claim that because cardio burns fat, the body stores more fat after the workout to prepare for the next exercise. They say that resistance training and High-Intensity Interval Training (HIIT) are better for fat loss.

I don't know if these claims are reliable. Could you clarify for us? Thanks!

—Wanna Lose Fat

Dear Wanna Lose Fat,

The Internet can be a good resource for health and fitness information, but it's great that you are double-checking your findings. Especially because there is not much support for the claim that long cardio workouts cause your body to store more fat. However, there is good evidence that high-intensity interval training (HIIT) is an effective fat-buster.

HIIT, or interval training, is characterized by alternating between periods of high- and low-intensity activity during a workout. For example, instead of running at a steady pace for 30 minutes, you could alternate between sprinting for one minute and then walking or jogging for two minutes. This fast/slow technique seems to maximize fat-burning. According to a study published in the Journal of Applied Physiology, participants burned more fat (and showed improved cardiovascular fitness) after only seven sessions of HIIT over two weeks. HIIT may work by training mitochondria (the cell's energy centers) to burn fat calories before carbohydrate calories.

In general, high-intensity or aerobic exercise burns more fat than low-intensity exercise. For example, you will burn more fat calories by running for 30 minutes compared to power walking for the same amount of time. What counts as "high" or "low" intensity exercise varies from person to person, and also depends on your heart rate. Check out Body fat and exercise intensity to calculate your target heart rate during a high intensity workout.

Many fitness experts also recommend mixing up your workouts to include weight training along with aerobic exercise in order to build muscle and burn fat more efficiently. Finding a variety of ways to exercise that you truly enjoy (whether it's cycling, dancing, running, or yoga) will also help you burn more fat in the long run — if you're having fun, you may be more likely to exercise longer and more often, and avoid burnout.

Before you begin interval training or start a new exercise regimen, you may want to talk with your health care provider. Columbia students can discuss their fitness goals with a personal trainer at Dodge Fitness Center. You might also want to check out CU Move, which is a good online resource to help keep you motivated for your workouts.

Good luck finding a fitness plan that works best for you!

Alice