Glucose + 0xygen ---->

[-V-MuayThai-V-]

So,

Glucose (C6H12O6) + Oxygen (O2) -----> ATP + CO2 (Carbon Dioxide) + H20 (Water)

This is what is known as aerobic glycolysis. It's funny, I learned that formula in high school when I took Bio Technologoy but I had no idea what it meant, where it happend in the body or what it did. Mainly because I didn't pay much attention in high school. So recently I learned what aerobic glycolysis was and what it meant and how it applied to real life by taking a nutrition class in college.

So you breathe out the water, and use the ATP for energy, but what happens to the water? I mean I thought excercise dehydrated you (from sweat loss). It's intresting to me that aerobic excercise produces water. How does this extra water affect hydration? Does this mean that lifting weights in very hot weather will dehydrate you faster than running?

Anyone care to discuss?

 

[Grady]

Hydocarbons are the fuel of life. Burning any hydrocarbon (sugar, gasoline, etc) produces water and carbon dioxide as the waste products. You expel the water just like you do any other excess water - perspiration, exhalarion, urination.

One thing to understand though is that the body is far, far more efficient than any gasoline engine. Therefore, the amount of fuel used up to provide you with energy is compartively very little. If you look at 2000Kcal/day as a baseline, and make a small pile of dextrose sugar (C6H12O6) that equals that, and then do some more math computing the amount of water liberated from that pile, and put that into grams or ounces, I doubt it would be more than a small glass or two of water at most.

 

[Rjkd12]

The body is not extremely efficient. The vast majority of energy consumed it given off as heat, and it is only slightly more efficient than a car. I just took biochem, so give me some time and I can get an exact number on this. Also, much energy is used to keep yourself alive (dna transcription, protein making (not for muscle) etc...) but those things are needed. I would assume a VERY small would contribute to muscle contraction, but I don't know if you were asking this at all.

So, what happens to the water? I would assume you breath the vast majority of it out. On a cold day you can see your breath because its full of moisture. You also urinate a lot of it out, and if you sweat. The vast majority of ATP that is produced is not used for muscle contraction. I mean, you can eat 2000 calories and not work out and not gain weight because you burn it staying alive. You burn those 2000 calories living, yet a hard workout may be anywhere from 100-500 calories, and 500 calories is a VERY hard workout. So, working out doesn't produce a lot of extra water for you at all, and the body can easily take care of it with the above resources.

Hope this helps.

 

[Grady]

The body is not extremely efficient. The vast majority of energy consumed it given off as heat, and it is only slightly more efficient than a car. I just took biochem, so give me some time and I can get an exact number on this. Also, much energy is used to keep yourself alive (dna transcription, protein making (not for muscle) etc...) but those things are needed. I would assume a VERY small would contribute to muscle contraction, but I don't know if you were asking this at all.

Thanks for the correction. My err.

If you have some numbers, I'd like to see em. A cursory web search found me the following source, which indicates that the human body is about 18% efficient, and a gasoline engine is 20% efficient, which is about what you stated, but the gasoline engine is only 1% efficient when used to haul around a car, a typical application, which makes it 18x less efficient than human legs to move proportional amount of weight.

Anyway, the relevant exerpts from the doc I read, if you are interested:

Human: "The human body, viewed as an engine that converts chemical energy from food into glucose, then into mechanical work is about 18% efficient (This number would increase if we included our heat production as well

 

[-V-MuayThai-V-]

Very intresting, thanks for the response. I learned about the body wasting most of the energy produced as heat. What's strange is that outside factors do not play a major role in this (unless of course we're talking about extreme temperatures). So basically humans are Glucose engines that release water and oxygen as a byproduct. Kinda like Hydrogen powered cars.

I just wanna get one thing clear, ATP is the only compound broken down for direct muscle contraction or energy use by the body, right? So your body creates ATP and uses it to create more by converting other Phospho-Creatine and Glucose to ATP?

 

[Rjkd12]

Grady, ok, this is whats in my notes. This is only for the electron transport chain though, and not for the whole body. But he said its 42% efficient, and an automobile is 30%. So, with phospho creatine and other methods of ATP production, I would assume that number to go down quite a bit. Also I don't know where my professor got this information, so I wouldn't trust it 100%. I think the 42% is correct though because he had some calculations regarding delta G and whatnot so in theory thats what it should be.

I just wanna get one thing clear, ATP is the only compound broken down for direct muscle contraction or energy use by the body, right? So your body creates ATP and uses it to create more by converting other Phospho-Creatine and Glucose to ATP?

Not quite. ATP is broken down, but so is GDP (but mostly for signaling), as well as cAMP. The last two are not as much for energy, but are similar to ATP.

The body has a few things that make ATP though, mostly NADH and FADH, also pyruvate and acetyl coA. All of these things are used in different types of reactions to get either products to make ATP, or ATP itself.

PCr (phospho-creatine) is used to make ATP from an inorganic phosphate and ADP. Glucose can either be aerobically or anaerobically made into ATP. ATP is used to make more ATP though, which is normally seen in the investment of 2 ATP to breakdown glucose and get 4 ATP plus a few other things.

Hope this helps and isn't more confusing haha.