The puzzle that is BG
2t9nty
Posts: 1,630 Member
So today I took a car to the shop to get two new tires. The wait was too long, and so I walked the 4 miles home and figured I would get a ride back when it was done. I walked at a reasonably brisk pace, and it took me a couple of minutes over an hour. Feeling all self-righteous about actually getting some exercise, I wondered how the glucose had responded to all this. I checked and it was 113. I was expecting lower.
I was 3 net carbs into my day at this point. I had taken meds. It was an hour after lunch when I started the walk.
What is up with this reading? I was expecting something under 100. If I had had more fat grams in my lunch might his have been different?
I was 3 net carbs into my day at this point. I had taken meds. It was an hour after lunch when I started the walk.
What is up with this reading? I was expecting something under 100. If I had had more fat grams in my lunch might his have been different?
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Exercise increases blood sugar. There's glycogen being used by muscle and replenished by GNG and a rise in cortisol too.
I doubt having more fat would've changed anything.
You might have a nice low reading a little while after. But not too close after.2 -
My uninformed guess is that the elevated BG is a result of elevated cortisol caused by the stress of exercise and that it drifted back down relatively soon.
I wonder about the effect of being in ketosis, as your body may not be sure what to do with the extra glucose...
I'll hunt around when I have a moment, but there are others who probably have this down cold. @cstehansen @midwesterner852 -
You say it was a brisk pace - do you have any idea what your HR was? If not, was this at a high level of exertion for you?
The reason I ask is because at a high level of exertion, or whenever you get over your "lactate threshold," exercise will increase BG due to production of lactic acid. This is at about 70% of your max HR. I'm assuming you live in the northern hemisphere? If it is warmer, your HR is elevated already and it takes less effort to reach that lactate threshold.
Also, what happened earlier in the day - the 12 hours prior? If you give a timeline of macros and insulin, that might help too. I assume you are a type 2 diabetic?2 -
midwesterner85 wrote: »You say it was a brisk pace - do you have any idea what your HR was? If not, was this at a high level of exertion for you?
The reason I ask is because at a high level of exertion, or whenever you get over your "lactate threshold," exercise will increase BG due to production of lactic acid. This is at about 70% of your max HR. I'm assuming you live in the northern hemisphere? If it is warmer, your HR is elevated already and it takes less effort to reach that lactate threshold.
Also, what happened earlier in the day - the 12 hours prior? If you give a timeline of macros and insulin, that might help too. I assume you are a type 2 diabetic?
I am T2. In terms of the previous 12 hours, I had bacon and eggs with coffee and HWC for breakfast and an ounce of peanuts with a chicken leg quarter for lunch. I left on the adventure about an hour after eating lunch. I took my metformin dose with breakfast, and I am not on insulin.
I was not winded or anything. It was not an especially high level of exertion. I was just just doing a 4 mph clip and having a good walk. I was not stopping to smell roses though. It might have been instructive to check heartrate, but that never crossed my mind. It was a warm day - 85 degrees probably. I was dressed in black (long sleeves too) and clergy collar with sandals. I am in the northern hemisphere.
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Sunny_Bunny_ wrote: »Exercise increases blood sugar. There's glycogen being used by muscle and replenished by GNG and a rise in cortisol too.
I doubt having more fat would've changed anything.
You might have a nice low reading a little while after. But not too close after.
I had a reading of 101 an hour after eating supper. I probably should have given it an hour after getting home and checked again.
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midwesterner85 wrote: »You say it was a brisk pace - do you have any idea what your HR was? If not, was this at a high level of exertion for you?
The reason I ask is because at a high level of exertion, or whenever you get over your "lactate threshold," exercise will increase BG due to production of lactic acid. This is at about 70% of your max HR. I'm assuming you live in the northern hemisphere? If it is warmer, your HR is elevated already and it takes less effort to reach that lactate threshold.
Also, what happened earlier in the day - the 12 hours prior? If you give a timeline of macros and insulin, that might help too. I assume you are a type 2 diabetic?
I am T2. In terms of the previous 12 hours, I had bacon and eggs with coffee and HWC for breakfast and an ounce of peanuts with a chicken leg quarter for lunch. I left on the adventure about an hour after eating lunch. I took my metformin dose with breakfast, and I am not on insulin.
I was not winded or anything. It was not an especially high level of exertion. I was just just doing a 4 mph clip and having a good walk. I was not stopping to smell roses though. It might have been instructive to check heartrate, but that never crossed my mind. It was a warm day - 85 degrees probably. I was dressed in black (long sleeves too) and clergy collar with sandals. I am in the northern hemisphere.
Hmm... the lunch might explain part of it - pairing the carbs of peanuts (though only 1 ounce, so...) with the fat in peanuts and chicken hind quarters (higher fat than breasts) and protein might explain it. Fat paired with carbs slows absorption. Restaurant pizza is the worst combination food with a big rise in BG many hours after eating it simply because of the carbs combined with fat and protein. However, your food isn't terrible. I might suggest 1 time isn't enough to worry about - try testing sooner after the meal next time (1 hr.) before exercise.
The good news is that if you are at 113 all the time, you don't have much worry about long-term complications. The concern with that as a fasting BG (especially for those who eat higher carb) is that you would have spent several hours at a much higher and more concerning level since the last meal. A prolonged time period over 140 has been found to greatly increase the risk of long-term complications. I bet you were never that high, but you might check sooner after eating just to see.0 -
The peanuts are just one net carb.
I have not seen a reading over 120 in a while - like maybe months, so I doubt it was ever 140. Typically I am 110(ish) an hour after eating and 105(ish) two hours after. Fasting has settled down to mostly low 100's. The last 5 days the fasting has been 99, 105, 98, 102, and 100.3 -
The peanuts are just one net carb.
I have not seen a reading over 120 in a while - like maybe months, so I doubt it was ever 140. Typically I am 110(ish) an hour after eating and 105(ish) two hours after. Fasting has settled down to mostly low 100's. The last 5 days the fasting has been 99, 105, 98, 102, and 100.
That is fantastic progress.0 -
That is fantastic progress.
Given where I started and the relatively short time, I am pretty pleased with where I am these days. I do get the occasional odd number for no good reason, and I have not quite wrapped my head around all the cortisol/glucose business. I had always worked on the assumption that exercise would burn off some of the free glucose roaming around the arteries. I will eventually sort this out in my head.
I am a very practical guy and have never really understood the "get in the car to go to the gym" thing. I try to stay reasonably active and will walk down to get the mail from the PO or walk the dog maybe. I am mostly the same way with my macros too. I try to eat fairly authentic food and don't go the protein powder route. I am mindful of the macros and will eat some olives if the sodium is low, but then I like olives and am looking for an excuse really.
The best bit about the LCHF for me is that it is well suited to my palate. I mean what I really want for breakfast is bacon and eggs. I really want butter and not some corn based butterlike product. Greens are better when cooked with some bacon grease. The diet gives me license and it is not a train wreck with glucose or the waistline.
The last blood draw had my liver enzymes at the (very) low end of the normal range, and I see that as a good sign after years of pursed lips and mumbling about NAFLD from the doctor. I see the enzymes as huge progress and a thumbs up for the WOE in general.
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My highest readings are ALWAYS after working out. I work out fasted in the morning or sometimes after BPC only. If my FBG is say 100, post workout will be between 125 and 155 depending on how strenuous the workout was. Cardio seems to raise it more than weight training. My highest post cardio was 176.
Generally it comes down within 2 hours to a more normal level.
Also, as was mentioned above, temperature plays a role as well. Higher temps = higher BG. If it is warm enough to break a sweat that is.
One of the reasons I fired my PCP was he basically called me a liar when I told him my highest readings were post workout. I had already done searches and found several articles on this topic so I knew it was not only possible but common.1 -
My blood glucose is always higher after exercise, including walking. I have heard it is common, more the rule than the exception. It comes down to a respectable reading 1-2 hours after. I don't worry about it because it's a normal occurring reaction to exercise.
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