Can anyone tell me which of these two days is the better workout for losing fat? Day 1 I ran slow for 3 miles; day 2 I ran slow for a mile and then walked fast for the last 2 miles. Here are the stats from my Polar watch:

Day 1: 46 minutes; 236 calories; 45% fat; heart rate @ 90% with a high of 151, average of 125, or 74%.

Day 2: 48 minutes; 181 calories; 56% fat; heart rate @ 106% with a high of 178, average of 106, or 63%.

If someone could break down exactly what the watch is telling me, I'd be appreciative. Thanks!

First of all, it sounds like you haven't set your HR correctly in the monitor. I'm not sure how old you are, but if 151 is 90% of your max, that would mean you are about my age - 58. However, if that's the case, I doubt very much you would be able to get up to 178 bpm; you'd be dead first.

So figure out how to set your max hr correctly first.

The best way to lose fat is to burn more calories - period. Also, it's good to break up your cardio sessions -- 1 day do steady state; the next intervals; the next, HIIT, etc.

I'm 52. The watch automatically adjusts the max heart rate, I believe. It just asks me for my age, height, weight, sex, and it tells me where the heart rate should be.

On day 2, it lists 236 calories as opposed to day 1, which is 181 calories, but the fat percentage is higher. So which is better?

It says the fat percentage is higher because you stayed in the fat burning zone longer, which is misleading. You may have burned more fat while actually doing a lower intensity exercise, but since you burned more overall calories, you'll burn fat past the point where you stopped exercising. The fat burning zone should pretty much be ignored, especially if you're only exercising for less than an hour. You don't go straight to burning fat anyway, it takes awhile for that to kick in. So yeah, the higher intensity workout is definitely the winner.

Thanks Corndoggy. I'll stick with the running. I say, "running," but obviously if you look at the stats, I'm barely "running." It took me only 2 minutes more to walk the same course. But, as you pointed out, I did burn more calories running. So, I think I'll stick with that. Thanks again for your input!

At 52, your max hr using the 220-age formula is 168. However, this formula is often way to conservative for people over 40, and is even more wrong for people over 40 who are in good shape.

Here's a site with 3 different calculation methods that will probably yield more accurate results for you.