i keep hearing that when u start doing cardio, it takes about 20 minutes for the body to start burning fat....meaning the first 20 minutes ur not burning fat. i also heard if u start off real intense, ull end up burning muscle. (these online articles are confusing).
but then when i get on the elliptical at the gym, it says for my age and weight, my heart rate has to be 127 to be in the "fat burn" stage....so if i get on the elliptical and 2 minutes later im at 127, am i burning fat? Or does it REALLY take about 20 minutes for the body to use fat as fuel...
i typically do cardio right after a nice workout, for about 20 minutes. so when i read these articles, i was like "wait, so the whole 20 minutes im not burning fat???"
05-01-2008, 03:45 PM #1
How long does it take to start burning fat??
05-01-2008, 05:08 PM #2
- Join Date: Nov 2004
- Location: Texas, United States
- Age: 48
- Posts: 1,704
- Rep Power: 312
If you stick to the 127 HR then you are burning fat the whole time after a workout. You are glycogen depleted from lifting, so you are going to be using stored fat for fuel unless you get above that HR. If you go higher then you are going to be breaking down stored protein (muscke) for fuel for the higher intensity work you are doing.
The 20 minute threshold is for someone that is not glycogen depleted. Supposedly it takes you about 20 minutes to use up your current glycogen and switch over to stored fat for fuel. Again, this is if you're HR is 127 or less.
You can also get a similar workout first thing in the morning before eating anything because you will be glycogen depleted. Low intensity "cardio" is the way to go to loose fat and spare the muscle IMO.
05-01-2008, 05:37 PM #3
- Join Date: Jul 2006
- Location: Washington, United States
- Age: 33
- Posts: 6,231
- Rep Power: 4941
You still burn fat even in the first 20 minutes you're doing cardio, the percentage just increases more the longer into the session you get.Only Those Who Risk Going Too Far Can Possibly Find Out How Far One Can Go
Forever Cutting (My Road to 10%):
05-01-2008, 06:17 PM #4
05-01-2008, 06:19 PM #5
- Join Date: Apr 2008
- Location: United Kingdom (Great Britain)
- Age: 33
- Posts: 1,374
- Rep Power: 255