Can You Trust the Heart Rate & Calorie Counters on Your Cardio Equipment?

With the New Year comes another surge in fitness-related resolutions. You’re ready to eat better, exercise more, and achieve the calorie deficit needed to lose weight. But before you step on that elliptical, can you trust what it says? If you are using any kind of cardio machine and rely on the information displayed, chances are it may not be as accurate as you’d think (or hope).

Does 400 Calories Really Mean 400 Calories?

Even with all of the new technology popping up in gyms everywhere, the cardio machines -- ellipticals, treadmills, Stairmasters, and stationary bikes -- still come pre-programmed. Many times, you press a button made specifically for fat burning or cardio, and you are prompted to enter your duration and weight. Fast-forward to the end of your workout 30 minutes later, and the machine says you’ve burned off 400 calories. Great work!  

Not so fast. Unfortunately, these machines cannot accurately measure each person’s individual caloric burn or metabolism. They are usually based on general calculations using numbers calculated from the male physique. In fact, the only thing that’s truly accurate is the heart rate monitor (usually in the form of two metal sensors that pick up your heart rate via your hand pulse).

Cardio machines with a premade “Fat Burn Zone” or “Cardio Zone” button can also be misleading. By default, these programs have a fairly low intensity.  Since the programs are not strenuous, chances are you are exercising at only 30 to 45 percent of your body’s capacity. After 30 minutes of low intensity cardio, you may only burn around 200 calories... even though the machine may be telling you it’s more like 300 to 400 calories. This is not an effective way to lose weight, since you’ll be more inclined to eat an extra 400 calories to make up for the deficit when in reality the gap was a lot smaller.  

Losing Fat Effectively

The key to losing fat effectively is doing cardio at low to moderate intensity for a longer period of time, ideally 60 minutes or more. To determine if you are exercising at an appropriate intensity level, try the “talk test.” If you are able to hold conversations and form complete sentences during exercise, it’s not intense enough. You should only be able to speak short sentences or yes or no answers. Being able to have a full conversation may indicate that your heart rate is barely above rest level, rendering your workout ineffective.

Listen in as Allison (Ally) Bowersock, PhD, discusses the numbers you get from all those devices and monitors and what to take as an approximate average and what you can trust is hard fact.