heart rate for fat burning


Jan 25, 2003
West LA
first off, does anyone go in here?

i know if you work out too hard, you burn muscle rather than fat. my question is where is the line drawn when working out at a high heart rate so that you don't burn more muscle than fat? i am trying to get very lean and losing any extra excess fat. im around the 10% body fat range. for the past 2 months i've been running about 5 miles a day for 4 days/week at an 8 min/mile pace. i have definitely lost fat, but i feel like i have lost lots of muscle too since i look smaller, and when i lift i can't lift as much as i did before.

If I follow the break down for heart rate between the 3 workout zones: fat burning, endurance, and cardio (increasing with heart rate). i don't get tired at all in the lower two zones. i can't even go slow enough to stay in the fat burning and break a sweat.
if i work out in the cardio zone, i obviously burn way more calories, but how much of that is muscle? i know that 9 calories = 1 gram of fat.

what should i do? work out more in the lower heart rate zone despite not feeling tired?


Oct 17, 2002
~60% HR for fat burning during exercise.

However, if you want to feel like you got a work out -and- burn fat... intervals. You'll boost your metabolism and burn fat after the workout.

Lastly, just a reminder... fat in food is NOT the same thing as fat on your body. You NEED fat in your diet, especially good fats.


Jan 25, 2003
West LA
what kind of intervals and how long? how is 2 minutes at a moderate pace and 1 minute sprints over a 20 minute period?


unique white person
Sep 21, 2001
I think you're suggesting cutting out beer and the good stuff in life.

You're fockin' nuts.
Whiskey and ice/water or vodka/oj kills beer dead.

To the original poster, cleaning up your diet is an easy way to lose some fat.

If you are worried about losing muscle mass, eat more protein.