A Straight Dope Classic from Cecil's Storehouse of Human Knowledge

Does running burn more calories than walking?

January 21, 2005

Dear Cecil:

I'm a runner, and I'm always having to take grief from people (especially my wife) who happily point out that you'll get the same benefit walking three miles as you will running the same distance, and you won't risk crippling arthritis of all your major body parts. So the other day I had a flash! Going back to high school auto mechanics and some hot-rod magazines, I explained to my wife that since I'm exerting the same force to move the same mass the same distance, I'm doing the same amount of work — but since I'm doing it twice as fast, I'm exerting two times the power and probably using twice the calories. My wife is pretty bright, though: she pointed out that if I run and exert twice the power in half the time, and then sit on my butt desperately trying to catch my breath for the other half of the time, then average power exerted is a wash. Is she right? Does running have any calorie advantage over walking, or am I really being that dumb (not like it would be the first time)?

Cecil replies:

A complicated question, often answered wrong even by those who ought to know. We'll take it by steps:

1. The unschooled view, which springs from the ancient instinct that pain = gain, is that running is better than walking because afterward you're sweating like a horse and gasping for breath.

2. Those with a semester or two of physics under their belts, on the other hand, reason that since the amount of work involved is the same, running a mile has the same impact as walking an equal distance.

3. However, this assumes that running and walking are equally efficient means of locomotion. Generally speaking they're not — running requires substantially more energy per unit of distance. Several factors contribute to this. Shall we start with entropy and the second law of thermodynamics? Eh, maybe not. How about aerodynamic drag, which increases with the square of the speed? Probably not something you need to worry about unless you've really been hitting the steroids. Here's something a little more relevant: Analyses of the biomechanics of walking vs. running suggest that walking is a more efficient gait except at higher speeds. The crossover point is somewhere around 5 mph, varying with the individual. At that speed, walking and running are equally efficient. Below the crossover point, running is less efficient, apparently because you lose energy absorbing the impact of the ground with your bent knees. Above it, walking falls behind because of the awkwardness of the racewalking gait. Gait is the critical issue, incidentally — running speed is irrelevant. Subtracting out the energy required just to keep you breathing, you'll use about the same amount of juice finishing the marathon in two hours or four.

4. To return to our main point, running consumes more calories per unit of distance than walking. For a person who weighs 70 kilograms (about 154 pounds), walking at 5 kilometers per hour (3.1 miles per hour) consumes 50 calories per kilometer, whereas running at 10 kph (6.2 mph) consumes 78 calories per kilometer.

5. Aha, you say, running is better than walking! Not necessarily, even if we narrowly define "better" as "consumes more calories." When you begin a workout your body is metabolizing carbohydrates, but as the minutes tick by you start burning fat — at minute 50 of light exercise, you're chugging along on a 75/25 fat/carb mix. Sixty percent of your maximum aerobic capacity (reached at roughly 75 percent of maximal heart rate, which is generally calculated as 220 minus your age) is optimal for fat burning; as exercise becomes increasingly strenuous you start burning more carbs. Some have seized on these facts to claim that sustained low- to moderate-intensity exercise is a better way to shed flab than going all out. The point is hotly disputed; I merely note that for the significantly overweight, walking can be easier on the heart, joints, etc.

6. At any rate, calorie consumption isn't the chief goal of exercise; cardiovascular fitness is. The American College of Sports Medicine says you should exercise three to five times a week in 20- to 60-minute sessions intense enough to raise your pulse to between 60 and 90 percent of your maximal heart rate. Such exercise should be aerobic, meaning something like running, brisk walking, biking, swimming, or cross-country skiing, as opposed to, say, weight training. Is running better than walking for this purpose? Depends. Running is certainly more of a workout per unit of time, but if your idea is that 15 minutes of running equals 30 minutes of walking, forget it — sustained exertion is the key. Then again, while any exercise is better than none, if your wife thinks a no-sweat half-hour amble around the neighborhood is the equivalent of your three-mile run, she's kidding herself too.

Related Posts with Thumbnails

Last Articles

arabian man wikipedia pronounce vietnam rose std mythical daggers constantly moving feet midget animals river rice brand touchscreen laptop games western sounds greyhound boarding number manly drink western movie music china doesn't exist mexican wedding ring vision exam dmv garcon meaning mount shoria retainer brite ingredients comfortmaker reviews tremolo lock dark coated pan lewis and hathaway midget newborn mp3 alarm clock donate encyclopedias dan coscino wehrmacht veterans birthday limerick dirty lolly pop guild general contractor rates mice in furniture japanese thank you cards can bolt cutters cut a master lock estes igniters not working how much is a bowling lane is marginata poisonous to cats tools to cut metal pipe how to watch the wire cost to move washer and dryer upstairs using steel wool to clean windshield rolling code garage door opener growing taller at 30 how to figure out what sound card you have no open toed shoes what does it mean when someone calls you boss average temperature of ice water 2001 ford taurus egr valve according to his business card, what did al capone do for a living woah oh oh oh oh techno song longest straight road in the usa contact keeps sticking to my finger best back to the future movie how long does it take flomax to work why are pistacios red ball drop live central time zone when was the last time a republican won new york will rayon shrink in the wash buy car no title women in mens dress shirt catch a cold idiom heaven and hell doors window film block view from outside energy to freeze water

Recent Additions:

A Straight Dope Staff Report by SDStaff Hawk, Straight Dope Science Advisory Board
A Straight Dope Staff Report by SDStaff Ken,
A Straight Dope Classic by Cecil Adams
A Straight Dope Staff Report by SDStaff Doug, Straight Dope Science Advisory Board
A Straight Dope Classic by Cecil Adams
A Straight Dope Staff Report by SDStaff Chronos, Straight Dope Science Advisory Board
A Straight Dope Classic by Cecil Adams
A Straight Dope Staff Report by SDStaff Doug, Straight Dope Science Advisory Board
A Straight Dope Classic by Cecil Adams
A Straight Dope Staff Report by SDStaff ScottInLA, Straight Dope Science Advisory Board