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Calorie Burn
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Chgosportsgal posted:
I have lost 40 lbs since last May. I work out 5 x's a week with various cardio and resistance training. However, I am noticing that my calorie burn is not what it used to be. Example: Yesterday, I did weight and core training for 40 min at burned 223 calories, where as the burn for this workout combo was well over 400 cals a month ago. So I guess my question is: The better shape you get into, does it take awhile to get the same calorie burn? Also, my resting heart rate used to be in high 80's or low 90's, now it's down to the mid 70's.
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Rich Weil, MEd, CDE responded:
First off, congratulations on your weight loss. It must feel great. As for calorie burn, you will burn fewer calories when you weigh less. However, the difference would not be 177 calories. It's too many. For example, a 200-pound man walking a mile would burn 160 calories. A 160-pound man walking a mile would burn 128. I don't know how you're monitoring your calorie expenditure, but do keep in mind that all equations that estimate it have error. It's very difficult to estimate energy expenditure accurately with equations as opposed to measuring it in the lab. You can try the WebMD exercise calorie counter:
http://www.webmd.com/diet/healthtool-fitness-calorie-counter

As for your resting heart rate decreasing, that could be partly a function of losing weight, and definitely a function of getting more aerobically fit. What happens is the heart gets more efficient and doesn't have to pump as fast to sustain life. Instead of the heart rate pumping faster, stroke volume of the heart increases. Stroke volume is the amount, or volume of, blood that the heart pumps per beat. Conditioned athletes have very low resting heart rates and very high stroke volumes for this reason.

You may also notice that at the same intensity while you're working out your heart rate may be lower now than when you first started training. For example, say your heart rate was 160 beats per minute while you jogged at 6.0 miles per hour on the treadmill when you started. Today, it could be 154 beats per minute at the same speed. Again, the heart is more efficient and so the stroke volume is higher now; that means the heart doesn't have to beat as fast.

http://www.webmd.com/a-to-z-guides/cardiac-output-topic-overview

Congratulations on getting more fit! Keep up the good work.


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Rich is an exercise physiologist and certified diabetes educator. He is director of the New York Obesity Research Center Weight Loss Program at St. Lu...More

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