Which Exercise Works Best?

I seriously have no idea.

But I'm going to find out!

Now that I'm 141 pounds--I started out at 164!--and have a 30" waist, it's not so much about weight loss for me as losing fat.

My electronic scale claims I'm 15% body fat. I started at 20%.

That's right: I used to have about 33 pounds of fat on my body, and now I have closer to 20.

But I would like to remove a bit of pudge, maybe be able to see my abdominal muscles just a bit?

So what should I do? I've been exercising. That helps.

But there's some debate about duration vs. intensity.

Namely, is it better to have a longer duration at a lower intensity? Or a shorter duration at a higher intensity?

Should I take an hourlong walk, or a 20-minute very brisk jog?

Partisans of the first approach claim that the longer you exercise the more of what you're burning is fat. After about an hour, you're burning almost entirely fat, hence the utility of this approach.

On the other hand, you're not burning that many calories overall.

Partisans of the second approach claim that if you raise your heart rate higher, it stays up longer and thus burns more overall calories, both due to the intensity and to the amount of time your heart rate is elevated.

I decided to find out--in my own, compulsive and semi-scientific way.

I figure: I know what foods keep me thin. How hard could it be to find out what exercise does the same?

So last week I went for a two-hour run!

For the first hour, I didn't get my heart above 140 beats per minute (bpm). Truthfully, this involves running a bit, then walking. It's rather pleasant and not terribly challenging.

Then I walked another hour (with short spurts of jogging) to keep my heart rate between 120 and 125 bpm.

A day and a half later, I had lost a pound and a half of fat!

Of course, the following day it was more like half a pound.

Then I jogged for 25 minutes, keeping my heart rate at 150 bpm. (It happened to be on a machine, but that can't make too much difference, I imagine.)

A day and a half later, I had lost over a half a pound of fat--and kept it off.

So the jury's still out. Obviously, one can't take two hours off that often to go running, even running very slowly.

The short-fast burst approach certainly seems less time-intensive.

I did another short, hard run today. This time a 15-minute warm-up and then 30 minutes of keeping my heart rate between 140 and 150 bpm--the wide range because it's harder jogging to get a constant rate than it is on a machine where you control the difficulty precisely.

So I will see! In a couple of days, I'll know if this is the fat-burning approach.

Even if it is, I enjoy the longer, less daunting runs--especially out of doors. (Who wants to be on a machine at the gym for that long?!) So I'm sure I'll try to work both ends.

Before, I was shifting around duration and intensity, but more to surprise my body. Consistently increasing duration and intensity is supposed to provide the famous conditioning effect--improving fitness, given enough time for recovery.

But if I knew the approach which burned more fat, it would certainly make fine-tuning this body of mine much easier.

I'll keep you posted.

--E. R. O'Neill