Running (cont.)
What are the fitness benefits of running?
Cardiorespiratory fitness (aerobic fitness or
"cardio") is the ability of your heart to pump stronger and more efficiently
and your muscles to use oxygen more efficiently. As you get more aerobically fit,
your heart will pump more blood and oxygen with each beat (this is called
"stroke volume") and your muscles will extract (or consume) more oxygen. For
instance, if you have 100 oxygen molecules floating around in your bloodstream,
a conditioned muscle might consume 75 molecules, whereas a deconditioned muscle
might only consume 30, or even fewer than that. In fact, elite distance runners
can be as much as three times more efficient at consuming oxygen than sedentary
individuals. Running improves your aerobic fitness by increasing the activity of
enzymes and hormones that stimulate the muscles and the heart to work more
efficiently.
What about running and burning fat?
For years, I've been asked if running burns more fat than other exercises. My hunch was that it might, but there was
never any proof. In particular, I was always perplexed by the fact that swimming
burns so many calories (in some cases even more than running), yet when you look
at the physiques of Olympic swimmers and compare them to elite long-distance
runners, you see a more defined, cut and leaner physique on the runner.
Adjusting for something called self-selection, where individuals of a certain
body type might select a specific sport (for example, lean people might choose long-distance running because they already have the body type for it), I never fully
understood why swimmers and some other endurance athletes weren't quite as lean
as runners. Then I read a study comparing fat burning in running and uphill
walking to cycling and it turned out that fat burning was 28% higher during
running and walking uphill than it was during cycling. The authors of the study
aren't sure why this is so, but it is suggested that the pounding of
weight-bearing activities like walking and running may cause more fat burning
than a seated exercise like biking, or an activity like swimming where there is
no pounding at all. This is intriguing research, but more needs to be done
before we truly sort out these issues.
Next: What about running and losing weight? »
Running: Related Topics