Thread: How do I know I am glycogen depleted ?

Originally Posted by elpasso1900

The 2-hours eating interval is to maintain my metabolism. .

Do not worry about this. You're metabolism will be just fine.

your body can store approximately 1000-1500 calories worth of energy in the form of muscle glycogen, depending on your size and level of conditioning. so, if you are not "topped off" to start with and if one of your workouts (the cardio ones perhaps?) burns about 1000 calories, you theoretically could be treading the depletion line.

this can be alleviated by eating carb-rich things during exercise - that is why you see tour-de-france cyclists snacking constantly during a 5-hr stage. also, if your urine has smells like ammonia, it means you have used up all your glucogen stores and your body has begun to breakdown muscle for fuel. basically means you need more pre/during-workout carbs.

Originally Posted by ErikTheElectric

My 0.02$: You WILL KNOW when you're glycogen depleted, it takes ALOT.

^ That.

Run into a brick wall at full speed, what you feel like afterwards is probably fairly similar to glycogen depletion.

Originally Posted by jj121591

your body can store approximately 1000-1500 calories worth of energy in the form of muscle glycogen, depending on your size and level of conditioning. so, if you are not "topped off" to start with and if one of your workouts (the cardio ones perhaps?) burns about 1000 calories, you theoretically could be treading the depletion line.

this can be alleviated by eating carb-rich things during exercise - that is why you see tour-de-france cyclists snacking constantly during a 5-hr stage. also, if your urine has smells like ammonia, it means you have used up all your glucogen stores and your body has begun to breakdown muscle for fuel. basically means you need more pre/during-workout carbs.

More like 2500-4000kcal, you store a lot in your liver.

One workout is nowhere near enough to become depleted unless it's ~2 hours of high intensity cardio with added maximum sprints and that's still only going to drain leg muscle glycogen(or whatever muscle you use) glycogen.
You are still burning fat along with glycogen during exercise, the glucose is more of a top off to provide the fast energy required unless you are doing full out sprints for 1 hour (and I mean sprint) you are burning a good chunk of fat.

It usually takes 3 days of zero/extremely low carbs and energy deficit with a ton of added cardio,HIIT etc. to become depleted for the Average Joe. It's not something that's easily achieved unless you are doing marathons etc. where it may become an issue after several hours.

Ammonia smell doesn't necessarily mean muscle breakdown, it simply means Gluconeogenesis rate is increased (non-carb substrate to glucose, usually protein) , so if you have a high protein intake it simply means excess circulating protein gets broken down to glucose.

Originally Posted by Znik

More like 2500-4000kcal, you store a lot in your liver.

Nah, it's not that much, you only store around 100g of glycogen in the liver. So the total would be around 2400 kcal.

Originally Posted by EmperorRyker

Nah, it's not that much, you only store around 100g of glycogen in the liver. So the total would be around 2400 kcal.

It is relative to size! But yeah you are correct, not sure why I wrote that, probably still sleepy from waking up.

~2400kcal is for the average Joe. High carb intake, more LBM and resistance training further increase glycogen stores.

~12-16g/kg LBM , with another ~ 500 packed on top, more with supercompensation.

Originally Posted by jj121591

your body can store approximately 1000-1500 calories worth of energy in the form of muscle glycogen, depending on your size and level of conditioning. so, if you are not "topped off" to start with and if one of your workouts (the cardio ones perhaps?) burns about 1000 calories, you theoretically could be treading the depletion line.

Per my polar watch with a chest HR monitor, I burn 1300cal per cardio session (1h and few minutes, 320+ watt if I am not mistaken). For my strength training, it usually goes for 3h and my HR monitor says 2500cal, which I think are overestimated.

this can be alleviated by eating carb-rich things during exercise - that is why you see tour-de-france cyclists snacking constantly during a 5-hr stage. also, if your urine has smells like ammonia, it means you have used up all your glucogen stores and your body has begun to breakdown muscle for fuel. basically means you need more pre/during-workout carbs.

The only time I eat during exercise is when I do steady cardio for more than 1h. I use energy gel 100cal (is this too low?) with caffeine mid cardio. Never felt the need during strength workout, I only feel the crash 3-4 hours later. Maybe that's the problem (no carbs or not enough inter workout)?

Regarding ammonia, I am not sure how that smells but true that sometimes, urine smells like hot vapor or funny.

Btw, thanks all who replied, really great informative feedback...

Originally Posted by elpasso1900

Per my polar watch with a chest HR monitor, I burn 1300cal per cardio session (1h and few minutes, 320+ watt if I am not mistaken). For my strength training, it usually goes for 3h and my HR monitor says 2500cal, which I think are overestimated.

You most likely burn one third of that for your cardio session and between a third and a quarter for your strength training session.

Originally Posted by elpasso1900

Are you sure ? I think 1/3 is way too low. Even when I use an incline treadmill or stairclimber, the calories these machines give me are just 100cal lower than my HR watch, usually at max difficulty level. So yes it does overestimate but I doubt to this extent.

Heart rate monitors have a 9-43% error rate.

The percentage error for heart rate was small across the devices (range: 1-9%) but greater for energy expenditure (9-43%). Similarly, limits of agreement were considerably narrower for heart rate (ranging from -27.3 to 13.1 bpm) than energy expenditure (ranging from -266.7 to 65.7 kcals) across devices.

http://www.ncbi.nlm.nih.gov/pubmed/2...?dopt=Abstract
The gym machines always overestimate energy expenditure by a lot as well, not sure if their calculation method just suck or if they do it on purpose to boost happiness among people who exercise.

http://www.runnersworld.com/peak-per...-will-you-burn

Op, give this a look.

As for glycogen depletion, for endurance workouts I usually feel very lightheaded.
For strength training, I usually can't train with the same intensity and volume and have less of a pump during workouts.

Originally Posted by elpasso1900

This article refers to optical HRM (wrist based), which I know are highly inaccurate. I am talking about chest based HRM, which are known to be quite precise in getting the real time HR.
Now remains the issue of calculating the caloric expenditure using HR data.
My view in this matter is this:
1)- those calculating caloric expenditure during an actual workout when the HR is high are accurate enough (+/- 100cal for 1h)
2)- those calculating total daily caloric expenditure are usually very inaccurate, for instance HRM based activity trackers. I suspect their algorithm is wrong for lower HR

For #2, do you know of a reliable application where I can upload my daily HR data and get a precise caloric expenditure out of it ?

The point of that study is that they are great for measuring HR, but HR is a terrible method of calculating calorie expenditure.

Originally Posted by Znik

, but HR is a terrible method of calculating calorie expenditure.

this^^^^^^^