Here's the answer from Dr. Dean Ornish, a clinical professor of
medicine at UC San Francisco:
"All things being equal, you will burn more calories by running an
hour than walking an hour. It is true that walking a mile will burn
more calories than running a mile -- although it takes longer to do
so. When you run a mile, you're burning mostly sugar, or
carbohydrates, which is how your body gives you fast energy in bursts.
When you walk a mile, it gives your metabolism time to switch from
burning carbohydrates to burning fat."
WebMD - Dean Ornish, MD Q A:
How many calories you burn depends on a variety of factors such as
fitness level, metabolism, weight and the intensity of the workout.
"Larger people burn more calories than smaller people,
particularly with activities like walking or stair climbing where they
have to carry their own weight," says Robert McMurray, professor of
exercise and sports science at the University of North Carolina at
iVillage - "How Many Calories Are You Using -- and Other Burning
Questions" by Carol Krucoff:
As far as how intensity affects a workout, according to an example
from the The President's Council on Physical Fitness and Sports, if
you were walking briskly for one mile and your friend was jogging,
you'd burn about the same number of calories if you walked for 15
minutes and he jogged for eight and a half minutes.
The President's Council on Physical Fitness and Sports - "Walking for
Exercise and Pleasure":
As far as a being better on the joints, walking is, without a doubt,
the better exercise. It's one of the safest exercises you can do and
it provides great cardiovascular benefits without all of the stress
that running puts on the body.
Yahoo! Health - "Walking Workouts" by Carol Krucoff:
According to Dr. Ann Gerhardt, a Sacramento, CA doctor who was forced
to walk for exercise after tearing her anterior cruciate ligament
"The other plus about walking is that if you do the technique
correctly and put as much effort into walking as you would running,
you can get the same aerobic benefit. You are moving almost every part
of your body."
CityXpress - "On the Run: Walking vs. Running" by By James Raia:
Calorie burning charts:
More fitness tools (calorie counters, etc.):
"walking vs. running" on WebMD and Google
So I guess this means that you win the bet? :-)