November 25th, 2009 How Many Calories do I burn while walking/running?

PONY ESPRESSO EXPRESS

Dear PE’s:

One of the things I have learned over the years is that there is no need to reinvent the wheel. I recently came across an excellent blog from Runners World, which I have reprinted below. It is a topic dear to my heart. I frequently deal with bariatric  (weight) issues in my practice. I have long been an advocate of jogging or running as a preferred method of exercise for weight control. Of course, for those who have significant orthopedic, cardiac or pulmonary issues, these may not be possible. Also, some individuals just abhor the thought. But, if you do run (which is likely if you’ve visited this site), here is some interesting information:

November 10, 2009

Nov. 10: Burn, Baby, Burn–Of Exercise and Calorie Burning

This blog has taken me longer to write than any other I’ve attempted–about 9 months. Here’s why: I can’t decide whether to make it simple or complex. It could go either way.

The topic is the energy expenditure (“calories burned”) of popular aerobic activities like running, walking, bicycling and swimming. It’s an important subject, especially for the millions who would like to use their exercise habits to maintain a healthy weight, or to drop pounds from an undesirably high body weight. And you’d think it would be simple. You just look up the food calories you consume every day, which are available from food labels, and web sites like NutritionData.com (a favorite of mine), books and lots of other places. Then you subtract your daily calorie output–the sum of your daily metabolism including work and family life, your thermogenesis (the calories your body expends in burning foods), and your exercise calories. What could be easier?

The metabolism and thermogenesis calculations are relatively easy to find on various web pages. But energy expenditures, particularly in useful forms (like miles and minutes), are not so easy to locate. Hence this blog.

For some reason, basic exercise calorie burning information is clouded in false assumptions and misconceptions. It’s one of the most misunderstood areas of fitness I know. For example, many if not most exercisers believe that walking a mile burns the same number of calories as running a mile. They figure: You move your body weight around a 400-meter track four times, and the work done is the same, whether you walk or run. Indeed, I believed this myself until five years ago when I read an insightful study, and then consulted with several experts in the field.

Here’s the real deal: running burns about 30 percent more calories per mile than walking, because running involves a completely different form of locomotion than walking. Yes, both use two feet and two legs. But runners “hop” or “bounce” across the ground, while walkers skim along without raising their center of gravity. All that hopping burns a lot of extra calories.

Other calorie-burning misconceptions arise because people get easily sidetracked by ideas like the “fat burning zone.” A recent New York Times “Well” blog confused many readers, to judge by the jumble of Comments, because it mixed “fat burning” into a column about calorie burning. But the former is almost completely unimportant, while the latter is critically important for those who want their exercise to help them control their weight.

In the table at the bottom of this blog, you’ll find a simple list of activities–running, walking, bicycling, and swimming–and the calories that a 150-pound male would burn doing them for a distance (per mile) or a time period (per minute). The per mile figures include both a “gross” amount and the much more meaningful “net” calorie burn. Also, since we all live our lives by the appointment book and the too-many activities we must do each day and week, I believe the per-minute, net burn view is the most important one. This is to the far right side of the table.

Here are a number of  other things you should know about the calorie burning table.

*** I’m confident of the running and walking figures. The others are a little less accurate because it’s difficult to get good research relating to them, and because they involve strange activities–like moving fast through a resistant layer of air, or moving slow through water, a much more resistant medium than air.

*** I’m not saying all the intensity levels (the speeds; or efforts) are the same. In fact, they surely aren’t. This would require some very advanced physiological testing. The intensities are simply ones I could find and feel relatively confident about.

*** The “gross” number of calories burned is the figure that everyone talks about, because it’s bigger than the “net” number, and we like bigger results. But the “net” figure gives a much clearer picture of the “extra calories” you’ve burned above and beyond your basal metabolic rate. For a 150# man, this is about 66 calories an hour. He burns these 66 calories even if he sits totally still for an hour. So they shouldn’t be counted as exercise calories, and they ARE NOT COUNTED in the two “net” calorie columns.

*** The far-right column, the net calories/minute, is the one you should look at when you only have 30 minutes for a workout, and you want to burn as many calories as you can. Here’s where the high-intensity exercises show their stuff. They don’t burn much fat, but they burn plenty of calories, which is the name of the game. Conversely, a low-intensity workout like walking doesn’t give you much bang per minute.

*** Running and walking are by far the two most popular calorie-burning exercises, so it’s interesting to know a few things about them. Your running calorie burn/mile doesn’t change as you go faster, or changes only minimally. This is a difficult concept, but has been proven many times. It would not be true if you could run 20mph, because then wind would become a big factor (as in cycling), but you can’t run that fast, so you don’t have to worry about it. Walking also has the same calorie-burn-per-mile up to about 5mph. But then it skyrockets; it actually surpasses running. Of course, almost no one walks that fast, and few even get up to 4mph.

*** For running and walking, your gross calorie burn/mile is directly related to your body weight, so we can produce simple formulas that you can use for your specific weight. In running, your gross calorie burn per mile = .75 x wt in lbs. For walking, it = .57 x wt in lbs.

The point of all this? First, to establish some benchmarks. Second, to make sure you understand that the harder you exercise, the more calories you burn per minute. Which is how we live our lives, minute by minute. This doesn’t mean that 6 miles of slow walking can’t burn as many calories as 5 miles of modest running. It can … almost. But the walking will probably take you two hours, and the running only about one hour.

Thirdly, to be just a little more honest with yourself about your exercise calorie burning, use your “net” calories burned per mile or minute.

So, there you have it. Now, take that Thanksgiving run, and ENJOY your TURKEY and FOOTBALL today

Happy Trails,

JRB