Fat Burning Question - Heart Rate Monitor ...

So my fancy new HRM which I TOTALLY adore - tells me that in my workouts (outside biking) I am only in a fat burning zone 35% of the time. I know that my 'hard' work out is almost the entire workout and that I might be working out too hard - but I LOVE pushing myself. HOWEVER, does this truly mean that I'm only burning fat 35% of the time? (Obviously it does) and what is the percentage I should be burning fat? I hate the idea that of 40 minutes I'm only burning fat 14 minutes or so (my math is usually really bad).

Any thoughts? Anyone know ... what should I do?

Bah don't even pay attention to that....go ahead and push yourself.  It just means that you are burning a high percentage of fat at that time....BUT that means 30% of the cals you are burning are fat (in the fat burning zone) and maybe 20% the rest of the time.  But if you are pushing yourself that that 20% is still going to be a lot more cals of fat burned.

Let says you workout moderately and burn 300 cals that means 90 of those are fat cals at 30%.  However if you push your self and burn 600 that means 120 are fat cals even at a lower percentage of 20%....clear as mud I hope.

I totally made up those percentages but the point is keep pushing yourself burning more cals is better...end of story

The "fat burning zone" is kind of a 50/50 proposition. If you burn calories slowly you'll burn a larger % of fat but if you go hard and burn more calories a smaller % will be from fat but because you are burning more calories more are fat-

 

Try looking thru the links posted on this thread for better explanations.

http://caloriecount.about.com/forums/post/287 56.html

Thanks guys I'll look thru it - so my question is - will I lose fat regardless of whether I'm burning fat or not burning fat - I guess I know the answer to that .......... the whole thing is a bit confusing to me - I'll read about it in the thread.

But it sounds like you're saying - go ahead and push yourself - I'm still burning calories?

Yes you are burning calories and you will burn fat as well. 

When you get above your "fat burning zone", you move from aerobic to anaerobic effort.  This is a fancy way of saying that you are working so hard you can't get enough oxygen to your muscles so you use up stored glycogen.  When you are in an aerobic zone, you only burn 50% fat because you still need glycogen to convert the fat to more useable forms.  So, for example, on my commute to work I do a lot of hill climbing and my HRM typically tells me that my %Fat is around 35 to 40.  But on the flatter route that I use for my commute home, my HRM typically registers 45 to 50%.  You can't count the glycogen based calories, i.e. calories that don't come from fat, toward weight loss because you have to replenish them for your next work out.  I know people who adjust their riding style to get high numbers from their HRM.  I gear my riding style to get from one place to another as fast as I can.