Calories, Joy, and a Box of Crackers (not in that order)

July 28th, 2010 by Amy Gonsalves Leave a reply »

 (Sad) Fitness Truth #2: Calories Burned While Exercising May Not Be As Many As It Appears

(Happy) Fitness Truth #2: You Continue to Burn Calories With an Elevated Metabolism Even After You Stop Exercising

I guess there isn’t anything worthwhile in hiding it, or even attempting to hide it.  I am an eater.  Yes, there are foods I dislike, but if it’s salty and if it’s crunchy and bite-sized, I’ll nearly always say “yum”.  I can put away a box of crackers at lightning speed. 

It’s not something I can say I’m proud of, but I do an okay job at making it through the day and fitting through the door.

So when I hear people talk about looking down at the treadmill readout, or at their heart rate monitor, and shout they just burned 600 calories, I know where that is coming from.  It’s coming from that place of “yum” that I myself enjoy so much.

And this is why it breaks my heart to tell you this: you really probably aren’t burning as many calories as you think.  I’ll steal from Cathe Friedrich yet again to explain: 

To begin with, cardio machines only give an average value for calories burned. The more accurate cardio machines will ask you to input your weight, sex and even height, but regardless the calories burned value displayed is only an estimate and not an exact value.

Still, the biggest mistake people make in calculating the extra calories burned from exercising is forgetting to subtract the calories they would have burned anyway if they had done absolutely nothing. The average person burns about 12 calories per pound of body weight each day just sitting around. The actual number of calories burned at rest (BMR) also depends on your metabolism. Metabolism rates are influenced by many factors such as height, weight, and age, but can also vary because of genetics and other factors. This is why some people can eat whatever they want and not gain weight, while others must keep to a strict diet to avoid gaining weight.

On average a 150 lb person will burn about 1800 calories each day without any exercise which translates into about 75 calories per hour. Therefore, if this 150 pound person did a one hour workout on the elliptical and the computer display said 500 calories were burned, technically it means only an extra 425 calories were burned from exercising on the elliptical during this hour and not 500 calories as the display indicated (500 – 75 = 425).

Depressing, isn’t it. 

Which is why I love this next little factoid so much: you will continue to burn some calories after you finish exercising.  Now, this depends entirely on how strenuously you exercise, what type of exercise you’ve engaged in, and every other factor that goes into your rate of metabolism to begin with.

You have probably heard about or felt the effects yourself if you live with diabetes and even if you don’t.  When I workout for more than an hour and a half, I need to check about 4 hours after I’m done because I usually head low about that time.  If I do strenuous interval workouts, it takes about 1-3 hours and if I do a long run, more like 6 hours.  Last night I ran 12 miles after work, and made sure to set an alarm for 2am.  I was 76 when I checked at 2am so I had some juice to help me sleep the rest of the night without crashing.

It’s kind of nice to know the effects of my exercise last so long.  It’s like a bonus

Maybe I’ll go open a box of crackers to celebrate.

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