Best Length of cardio in order to burn fat?

**YouAintKnow330** · 02-17-2009, 08:02 PM

What is the recommended cardio time for burning fat.

I was one time told that at medium pace you do not start to actually burn fat until 40 minutes into your cardio... is there any truth behind this?

***FireGuy*** · 02-17-2009, 08:05 PM

It really depends how full your glycogen stores are. This is why so many people advocate doing cardio first thing in the morning or after working with weights. Your glycogen is much more depleted forcing the body to find an alternative fuel source. If you are in the right aerobic range most of this fuel source will be from stored adipose tissue sometimes referred to as bodyfat.

**xXthehulkXx** · 02-17-2009, 09:41 PM

^^^ x2. that's why i do mine after an intense workout.

**Lemonada8** · 02-18-2009, 03:37 PM

as long as u can keep ur HR down, you will burn fat instead of glycogen... u need to keep ur ur RER below ~.85 (that is the ratio of CO2 released compared to O2 consumed, which required a fancy pants test which if you are completely serious then u should do it, but for here....) keep ur HR at roughly 75% max HR and u should be fine..

**xnotoriousx** · 02-18-2009, 05:10 PM

I would say no less then 30 minutes, if you're very determined to burn some get a hour in. Like Lemon said, keep the HR around 75%

**POPS** · 02-18-2009, 05:56 PM

are you using 75 % just as a guide or using the formula : 220 - age x 75%. Doesnt the fat burning zone start at 65%?

I have been doing 45 min on treadmill m/t/t/f 12 deg inc. 3.8 mph and my h.r. stays between 120 and 130. On Wed I change it up by doing the eliptical for 30 min and h.r. is around 130. For me, everything is working just fine unless you guys think otherwise.