Can anyone explain?...

Finzi

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366
I'll start with an apology - I know that these figures are really not bad, and that some people are battling much higher figures (cos I know I always mind a bit when someone complains that they can't get below a 6 or whatever...)

BUT, that said, I just don't understand the relationship between my bg's and eating. To take today as an example - I never actually test first thing, because I think I have dawn phenomenon. So, bearing in mind I had a breakfast that had 7g carbs total: I went for a long walk after breakfast, and a long walk before lunch, no snacks or anything in between (I never snack) - my 1pm pre-lunch reading was 7.6. That's very much on the higher side for me - I'm thrilled with fives, sixes are typical, sevens are disappointing, and eights even more so (although I've only ever had one 8). Then, two hours post a zero carb lunch - 5.9. How can my sugar be lower after a meal than before it? (And that seems to happen quite often). And two hours after a 21g carb dinner it was 6.6. So still lower than my pre-lunch. Could I still be having dawn phenomenon at 1pm? Does exercise raise sugar in the short term (the reading was immediately after a long walk).? Am I over thinking this? :)

One reason I want to know reasons is that the 7g of carbs in my breakfast came from a slice of Burgen bread, and if it means I shouldn't have Burgen again, that's fine, I don't really mind much, I'm trying to keep to as close to zero carbs as possible.


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Yorksman

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2,445
Type of diabetes
Type 2
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Finzi said:
BUT, that said, I just don't understand the relationship between my bg's and eating.

Hi Finzi,

It's not a direct relationship. In theory, what you eat is absorbed but if you don't eat anything or don't eat enough, your liver will still put extra in your blood. A healthy person could, for example, not eat anything at all for three or four days and still have decent BG levels.

Just as eating causes changes in blood glucose and insulin, so does exercise. Your muscles need extra energy. In your example, it may be that having gone for two walks has told your liver to put glucose into your blood to cope with the requirement for that extra energy. It can do that before the insulin response. Your insulin response is working however because it did bring it back down. Perhaps not as quickly as with a healthy person, but better late than never.

You could try taking a blood test, going for a walk and then taking another blood test as soon as you get home and then another one hour after. That way, you will get to see the effect of exercise on BG levels without clouding the issue with food. Overall, exercise is good because it improves insulin sensitivity but that is longer term.
 

Finzi

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366
Yes, maybe I should test before and after exercise. Oh dear, I'm going to get through a lot of strips lol. But what you say does make sense, and in fact the highest reading I've ever, ever got (to my knowledge) was 9.8 and that was immediately after a *very* vigorous hill walk (much more strenuous than I'd ever normally do), on an empty stomach.

I'll have to try to not mind that exercise might raise my blood sugar. That seems a bit demotivating :(




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Yorksman

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2,445
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Type 2
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Normally healthy people get the same dawn phenomenon and the same spikes after carby food and exercise, it's just that their insulin response is swifter that a type 2. Exercise improves that response in the long term but there are a number of processes going on. Exercise anyway can be of several different types with changing levelsof activity and periods of duration. Here is a paragraph from a study entitled Exercise and Type 2 Diabetes:

"Fuel mobilization, glucose production, and muscle glycogenolysis. The maintenance of normal BG at rest and during exercise depends largely on the coordination and integration of the sympathetic nervous and endocrine systems.

Several factors influence exercise fuel use, but the most important are the intensity and duration of physical activity. Any activity causes a shift from predominant reliance on free fatty acids at rest to a blend of fat, glucose, and muscle glycogen, with a small contribution from amino acids. With increasing exercise intensity, there is a greater reliance on carbohydrate as long as sufficient amounts are available in muscle or blood. Early in exercise, glycogen provides the bulk of the fuel for working muscles. As glycogen stores become depleted, muscles increase their uptake and use of circulating BG, along with FFA released from adipose tissue. Intramuscular lipid stores are more readily used during longer-duration activities and recovery. Glucose production also shifts from hepatic glycogenolysis to enhanced gluconeogenesis as duration increases."

You're measuring two things, changes in BG levels due to exercise and changes in BG levels due to lunch but, you're doing them at the same time, so the results are not clear. On the positive side, since your BG has come down from 7.6 to 5.9, you know something is working right. You say your lunch was zero carb so, the meal shouldn't really affect the readings. The only thing you don't know is why you had the 7.6 before lunch. I guess that's exercise. They're all respectable figures anyway.
 

Finzi

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366
Thank you Yorksman! That's really interesting! Trying to figure out now from that what is the best kind of exercise to do -prolonged and moderate, or short and intense (I can't do long and intense I'm afraid!)


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PhilT

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94
Type of diabetes
Family member
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How can my sugar be lower after a meal than before it? (And that seems to happen quite often).

Eating protein often gives an insulin response, even without carbs, so if your body responds it will reduce the blood sugar.
 

Yorksman

Well-Known Member
Messages
2,445
Type of diabetes
Type 2
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Finzi said:
Trying to figure out now from that what is the best kind of exercise to do

I have no option but to do three or four short periods of 3 or 4 mins. Started with just one session but will work upto 6 or 7. I used to do some floor exercises but have now got a rower. Best way of describing it is like walking up a moderately steep hill for 3 or 4 mins without stopping. The more times you do it, the easier it gets. The legs start to feel the strain, the pulse quickens and towards the end breathing is faster.

You may be interested in the BBC2 Horizon programme entitled The Truth About Exercise. Although the exercise bit is interesting, there is a lot about blood glucose and insulin response. The presenter is worried about getting diabetes. It's worth a watch as it might answer some of your questions.

http://www.bbc.co.uk/iplayer/episode/b0 ... _Exercise/
 

Finzi

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366
I will definitely watch that! I have a vague memory of watching that when it came out, but I wasn't diabetic then and the insulin stuff would have gone in one ear and out the other.


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