"In the Zone" Question

[Cynthia8828]

Hello Everyone. I hope everyone had a wonderful holiday season.
I have a question about a gift I received. DH bought me a heart monitor for Christmas. I used it last night and noticed something. Of the 40 minutes I did cardio, only 20 of those minutes were in the zone. I had a really tough time staying in there as well, and constantly had to modify in order to not work the high end.

My question is this. When my heart rate is higher than the "zone", am I no longer burning fat. I felt like with all of those modifications that I was making, I was barely working out. It was very hard to keep the energy up, and I was constantly doing low impact trying to keep the rate down. According to the charts, my zone is between 125-150 for my age, etc.

Does anyone else experience this difficulty when working out? I can't think that I am out of shape so bad that my heart rate constantly goes over, but who knows? I feel great and I feel in better shape then ever! I am an advanced exerciser and have worked out 6 days a week for a year now. Does any of this make sense. Some advice would be GREATLY appreciated.

Thanks,
Cynthia

 

[Dawn W]

I dont know your age or fitness level but you probably can burn fat at a higher heart rate. The percentage of calories you butn from fat will just go down. I'm going to make up numbers here, so don't use these as facts.

If your heart rate is between 60-70% of maximum you will burn 40% of the calories you burn from fat. Let's say for an hour that's 300 calories. So 120 calories are from fat. At 70-80% it will only be lets say 30% of say 400 calories, however since the calores you burn are more the total fat you burn should be the same. The other calories you burn will be from the carbs, so you can eat more ;-)

I hope this made sense.
Dawn W

 

[debbieNIR]

I think that many people found they were exercising too hard when they started using a heart rate monitor. It is an excellent tool.
You do not necessarly have to work harder to work smarter.
The above post adresses the truth about working within upper and lower ranges of the aerobic working heart rate range.
I don't know what range you entered into your monitor.
My 60-85% is 110-156. My anaerobic threshold is therefore 156.
The problem is if you are actually going so high that you are in the anerobic region. This region is only meant for short spurts during interval training. It is neither healthy or smart to train in this region other than during interval type training.
I am speaking of > 85% maximum heart rate.
You cannot burn fat without oxygen; so, anaerobic work can only use stored gylcogen or broken down lean body tissue (the body is capable of converting protein to glucose in a situation where all glycogen is depleted and the anaerobic threshold is passed).
So, you are NOT burning fat if you work out too hard!!
As I said, it is actually beneficial to stay anerobic for short intervals (1-3 minutes) followed by recovery in the aerobic zone.
I was surprised at how I had to slow down when I first got mine too! You really will get more benefit if you use it though. High impact work really increases the heart rate and sometimes you are having so much fun, you cannot count on perceived exertion!!
One last issue is that you may have an unusually low resting heart rate. Most people use the general 220-age formula for maximum heart rate. There is a more accurate way to determine maximum heart rate which factors in your resting heart rate. I can get it from my ACE text if you want it. I am drawing a blank off the top of my head!
If you have a relatively normal resting heart rate (say 70-80), the basic formula works fine. You will find though that if you are in excellent shape that your RHR may be as low as 55.
If you factor this in, you will be able to go higher (maybe about 10 BPM) and still be aerobic.
Hope that was not too depressing!