# I just don't understand...



## Amanda102

I don't understand how exercise lowers your sugar levels. This may seem stupid, but it has got me puzzled! If insulin is needed to get the glucose out of your blood and into your cells, how come sugar seems to make it on its own when you exercise??? It doesn't make any sense to me.  I know someone will be able to explain this.


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## Northerner

It works in a couple of ways as far as I know. Firstly, your cells become more insulin sensitive when you exercise. Cells have a certain number of insulin receptors and the number of these increase , allowing the cells easier access to glucose for energy. In a non-diabetic the amount of insuln is finely controlled by the mechanism that spots when BG is too low, so pancreas produces glucagon to get the liver to increase BG. In insulin dependent diabetics this doesn't happen so BG may drop too low unless supplemented by more glucose in the form of jelly babies etc.

Up to a certain point muscles can use their stores of glycogen to perform exercise, and after that either use blood glucose or, if you are sufficiently fit, metabolise fat stores. When I run 5 miles my BG doesn't change, but beyond that the muscles use BG so I have to supplement it with jelly babies.

Sorry, I probably haven't explained it very well!


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## Medusa

also worth bearing in mind the first twenty mins of exercise burn what you have eaten.... the insulin converts what you have eaten (energy you put in your body) into what you are using up whilst exercising (like fuel in a car) so sugar levels will drop and after the first twenty if you have put too much insulin in or not eaten enough you will be low before your body starts burning off the fat reserves in your body.... nope my explanation is not clear either.......


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## Robster65

There's also the anaerobic exercise that causes some complicated chemical bonding to take place and provides temporary fuel in that way. Which is why, when doing anything 'grunty' (weightlifting, sprinting, etc), your BG can rise initially, only to crash later.

I think it ties in with what Northerner was saying about the muscles burning glycogen first, then looking for glucose from the blood.

As far as I know, muscles can't utilise glucose from the blood without some insulin present.

Rob


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## Copepod

Runsweet is a website aimed at helping people with type 1 diabetes to participate in all forms of sport and has some good explanation pages eg http://www.runsweet.com/DiabetesAndSport.html


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## Northerner

I'm going to re-read my copy of The Diabetic Athlete's Handbook!


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## Amanda102

Well I am not a whole lot clearer, but certainly had a chuckle as I read some of the replies. I guess there is no easy way to explain something as complex as the workings of the human body! I might have to accept the age old response of, 'because it just does!'


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## Robster65

Hi Amanda.

Is your question more about why the blood sugar rises after some exercise and drops after others, or just why and how the body uses insulin to get the glucose into the muscles as fuel? 

Rob


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## Amanda102

Robster65 said:


> Hi Amanda.
> 
> Is your question more about why the blood sugar rises after some exercise and drops after others, or just why and how the body uses insulin to get the glucose into the muscles as fuel?
> 
> Rob



I think my question was confusing! When my daughter plays football she either reduces her insulin or eats extra carbs. This indicates that her body is getting the sugar out of the blood stream without or with less insulin. That is the bit I don't understand. Now I'm typing though, the earlier response that exercise makes the body more insulin sensitive would seem to make sense.... I suppose I was wondering if hypothetically a person could totally replace taking insulin by exercising loads (not something I would ever consider as an option, but just curious!). 

You all said no question is too silly when I joined ... I guess I am really putting that to the test now!


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## Otenba

You've hit the nail on the head Amanda... your body uses insulin more efficiently when you exercise.

The highs after exercise can be caused by a lack of enough insulin, particularly if you're very sure that you did not hypo to cause the high. When this happens, be careful not to correct too keenly because your body can be still sensitive which can potentially make you hypo if you do correct. Give your body a chance to use the insulin you do have that's still working (like from your last meal for example) and this can allow it to come down more safely by taking advantage of the insulin sensitivity.

We're so used to hearing that food makes you rise and insulin makes you lower that we can easily find the idea of needing insulin for exercise hard to comprehend. I know I struggled to understand it at first.


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## DeusXM

> I suppose I was wondering if hypothetically a person could totally replace taking insulin by exercising loads (not something I would ever consider as an option, but just curious!).



Even though your daughter is a T1, as long as she is treating her diabetes,  there is always insulin present in her body. As has been discussed, exercise makes your body use this insulin more efficiently and causes muscles to extract more glucose from the blood via insulin. 

I suppose one way of looking at it is like blood glucose is people, muscles are a house, and insulin is like a door on a spring. Usually, the people go into the house, the door shuts behind them, so the door has to be reopened every time and slows down how many people (glucose) can get in. More insulin means more doors, meaning more people get in.

When you exercise, your muscles do the equivalent of shouting 'free beer and money for everyone!', people rush through the doors and because so many people are trying to get in, the springs gets stretched, the doors don't close as well as they should, so more people can get in, so you either need fewer doors (less insulin) or more people (more glucose)

You'll note though that either way, you still need the door. Otherwise you've got muscles shouting about free beer and a load of puzzled people left on the street, getting grumpy and causing damage because they can't get inside. So exercise alone cannot be a treatment for people with T1 - although it can work well for certain types of T2.


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## Otenba

I like the explanation story DeusXM! Very good! XD

"Free beer and money! Woo hoo!" lol


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## pgcity

DeusXM said:


> Even though your daughter is a T1, as long as she is treating her diabetes,  there is always insulin present in her body. As has been discussed, exercise makes your body use this insulin more efficiently and causes muscles to extract more glucose from the blood via insulin.
> 
> I suppose one way of looking at it is like blood glucose is people, muscles are a house, and insulin is like a door on a spring. Usually, the people go into the house, the door shuts behind them, so the door has to be reopened every time and slows down how many people (glucose) can get in. More insulin means more doors, meaning more people get in.
> 
> When you exercise, your muscles do the equivalent of shouting 'free beer and money for everyone!', people rush through the doors and because so many people are trying to get in, the springs gets stretched, the doors don't close as well as they should, so more people can get in, so you either need fewer doors (less insulin) or more people (more glucose)
> 
> You'll note though that either way, you still need the door. Otherwise you've got muscles shouting about free beer and a load of puzzled people left on the street, getting grumpy and causing damage because they can't get inside. So exercise alone cannot be a treatment for people with T1 - although it can work well for certain types of T2.



Wow. It makes sense now. I thought it was all a bit random but will now assess how much insulin is left and how long since eating to see if I can predict when I need more doors.


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