So low intensity cardio burns calories from fat and not glycogen?

[1800_Cool_Guy]

Is this correct?

[heinstein]

Sorta. It's more like you burn the glycogen and turn fat into more glycogen at a similar rate.

[MarkSuave]

Is this correct?

To my understanding, your body's first line of fuel is sugar already in the blood, then glycogen (stored sugar), then it starts to metabolize fat into acetyl-COa (which is what blood sugar, glucose, is metabolized into to start the ATP production). So low intensity for a long time would burn fat, but that I mean long. Some people do HIIT to speed it up, you can apparently burn just as much doing 15 minutes of High Intensity Interval Training (HIIT). You do really fast, hard exercise to burn glycogen stores away and then do a longer period of low-moderate intensity cardio to keep burning fat as energy.

[1800_Cool_Guy]

Just wondering. I've been walking on the treadmill at 3.5mph for 1hr 20mins maybe 3-4x a week depending on my schedule. I burn about 380 calories each time according to the thing. 2 other days I do high intense for 30 minutes.

[DrJKiel]

Is this correct?

Not really, but it depends on several factors. It depends on your blood sugar when you start. It depends on when your last meal was. It depends on how much intense physical activity you have had in the last few days (i.e. what are your glycogen stores). The bottom line is your body will almost always use glycogen first . This is smart in an evolutionary sense if you think of glycogen as a "short term energy" supply and fat as a "long term energy" supply.

Learn more

Dietary fat metabolism- https://www.youtube.com/watch?v=DJEeqogKiJI

Carb metabolism- https://www.youtube.com/watch?v=U7E_Fgk8Q20

Protein metabolism (if interested) - https://www.youtube.com/watch?v=YWooxqV18kc

[MarkSuave]

Not really, but it depends on several factors. It depends on your blood sugar when you start. It depends on when your last meal was. It depends on how much intense physical activity you have had in the last few days (i.e. what are your glycogen stores). The bottom line is your body will almost always use glycogen first.

this

[1800_Cool_Guy]

So low amd high intensity cardio are the same if you burn the same amount of calories?

[heinstein]

So low amd high intensity cardio are the same if you burn the same amount of calories?

No!

[Paranoy]

Sorta. It's more like you burn the glycogen and turn fat into more glycogen at a similar rate.

The body can only produce around 20g of glucose from glycerol in an entire day, so during the course of a session it wont be much at all.

So low amd high intensity cardio are the same if you burn the same amount of calories?

Not during the time of the session but during the course of the whole day it may very well work out to be the same. During low intensity you will use more fat as a fuel source compared to high intensity which favors glycogen more. But if you burn more of one source during this activity, your body simply burns more of what is left during normal activities across the rest of the day so it cancels out. The only advantage of high intensity is you burn more calories in a shorter period of time so its a more time efficient activity.

[SuffolkPunch]

So low amd high intensity cardio are the same if you burn the same amount of calories?

Yes

For the same net daily calorie balance, the same affect will be achieved. You shouldn't worry about substrate utilisation at the time of exercise because high intensity will have a greater fat burning effect at other times (i.e. when the body is replenishing glycogen and dealing with lactate etc)

[TheRedHerring]

Yes

You shouldn't worry about substrate utilisation at the time of exercise because high intensity will have a greater fat burning effect at other times (i.e. when the body is replenishing glycogen and dealing with lactate etc)

How does the body burn fat during glycogen replenishment?

[Chaosvash]

High intensity is good for heart/cardiovascular health, the increased heartrate is also good for your overall metabolism for a while after the cardio.