Intensity of Exercise and Blood Glucose levels

[Soror]

I'm curious to know what effects others have seen from various types of exercise on BG levels. I have good after meal readings but have struggled with my fasting levels for a couple of years, not horrible but in the pre-diabetic range(105-110 on my normalish paleo diet and 115-120 with some indulgences). I recently started running and have noticed the morning after a run my bg levels are in the normal range, interesting to me is that I show more improvement in bg levels from a 1 mi run (at a slow 11 min pace) than 2+ hrs of moderate hiking.

 

I avg about an hr of walking a day(various paces with some sprinting to keep up with dd3yo on her bike), do Yoga(moderate intensity- I leave sweaty), Silks(kicks my butt but not heavily cardio), have tweaking the timing of my meals, tried various pre-bed snacks, different supplements and various amounts of carbs but none of those things have been close to having the same effect as the running has so far. I told dh that I might need to take up daily mile run solely for the effect on my BG. The only problem is that my body only tolerates so much and when I have too much activity it revs me too much and I can't sleep(like tonight).

 

Yesterday instead of running we did fairly intense biking for around an hr(to be fair I also did about 45 min of Silks and a short brisk walk) and yet again my bg levels are in the normal range. I did some searching yesterday and I kept coming up with hits about how moderate exercise is good but did not find more intense exercise mentioned. Even more curious to me is that the 1 mi run did more for my bg levels than restricting my carbs to sub 50g a day and with carb restriction I'd have difficulty with it going too low if I didn't eat after waking but I haven't had the same problem with running so far with a lot higher intake of carbs(still paleo).

 

 So, does anyone else have data on exercise intensity and how it effects their bg levels? I know individuals vary but I'm very interested to hear from others.

[nevergiveup]

No idea about the exercise but excess protein can be converted to glucose through gluconeogenesis, so even though you are low carb with paleo, you might be eating too much protein?

[JumpyTheFrog]

More intense exercise uses up more glycogen and glucose (as a percent of calories) while lower intensity burns more fat (as a percent). If you burn up some glycogen, the next time you have carbs the glucose first goes to refill the depleted glycogen, leaving less behind for your blood. (I may have also read that muscles refill glycogen stores without the use of insulin, but don't hold me to that.) This is aside from exercise reducing insulin resistance or affecting cortisol levels.

[Laurie4b]

What is your heart rate? If you use the 220-your age as your maximum formula; 50-70% of that is moderate. 70-85% is vigorous.  I would check your heart rate and keep track of the results in terms of impact on blood sugar. You may have hit your sweet spot. 

Edited March 6, 2016 by Laurie4b

[Soror]

Yes, I've read that about protein. I've tried varying my diet this way and that with little effect. When I try to go more veg it is worse. I'm just really tired of tweaking it trying to find some magic thing that will fix it. I had thought I would just live with my fbg elevated come what may and was surprised to see this effect from more intense exercise when I haven't had an effect before.

 

 

[Soror]

What is your heart rate? If you use the 220-your age as your maximum formula; 50-70% of that is moderate. 70-85% is vigorous.  I would check your heart rate and keep track of the results in terms of impact on blood sugar. You may have hit your sweet spot. 

 

I don't have a heart rate monitor so I don't know. I go for the level that is a challenge but sustainable, not panting but sustained conversation is challenging. The running (and biking for that matter) naturally vary in intensity though with the hills.

More intense exercise uses up more glycogen and glucose (as a percent of calories) while lower intensity burns more fat (as a percent). If you burn up some glycogen, the next time you have carbs the glucose first goes to refill the depleted glycogen, leaving less behind for your blood. (I may have also read that muscles refill glycogen stores without the use of insulin, but don't hold me to that.) This is aside from exercise reducing insulin resistance or affecting cortisol levels.

I do believe there is something to do with cortisol b/c it certainly gives me energy and as I said if I do too much I got too much energy- which is bad of course- I'm trying to find the sweet spot of enough to lower bg but not so much to effect sleep. I'm also thinking that perhaps my body will adjust as long as I don't push too hard, of course I don't know what too hard is until after the fact. 

[Soror]

I was thinking of my day yesterday this is what I ate:

 

am snack: apple w/ cocomilk(full fat) + chopped pecans+ coco flakes (lightly sweetened)

brunch: 6 oz tuna +2-3 cups homemade coleslaw (hardly any sugar in this)

lunch: 2- 1/4th lb burgers w/ 3 cups kale 

after bike ride snack: banana 8oz GT's kombucha

supper: 6 oz sirloin, sweet potato, green and wax beans

 

Pretty high in proteins and not really low carb either, usually that would be at least 100+ fbg level, I was at 92 this am

[EmilyGF]

How about this article?

 

From the article:

"In intense exercise (>80% VO2max), unlike at lesser intensities, glucose is the exclusive muscle fuel.30Catecholamine levels rise markedly, causing glucose production to rise seven- to eightfold while glucose utilization is only increased three- to fourfold."

 

"A single session of continuous high-intensity exercise resulted in 60 minutes of postexercise hyperglycemia,49 while both a single session of HIT,50 and a 2-week training program51 have been shown to improve postprandial glucose control over a 24-hour period following exercise."

 

"In type 2 diabetic patients, a low-volume 2-week HIT program increased GLUT4 protein, a marker of insulin sensitivity, and decreased average blood glucose 48 to 72 hours postexercise. The protocol used was less intense than SIT and was acceptable to study participants. However, unlike with moderate-intensity exercise, blood glucose levels tend to be higher in both type 1 and 2 diabetic patients during and in the 2 hours immediately following intense exercise due to rising catecholamine levels promoting glycogenolysis, and these levels may remain high in the 2-hour post-exercise period. HIT depletes muscle glycogen and it is possible that after catecholamine levels decrease in the post-exercise phase, a period of increased peripheral uptake of glucose follows as glycogen stores are replenished."

 

And see the article for more -  I am (thankfully) not that familiar with this subject, so you'd probably do a better job reading it than I did! But it looks like HIIT may be a good thing for us all (but not for me until I heal my postpartum core, but that's a different issue).

 

Emily

[Soror]

Thank you Emily for your sleuthing. I'm heading out the door now but want to read this more in depth later. I'm not actually a big fan of HIIT as it is generally too intense for me, will have to read as to what it says about various types of exercises and decipher.

[Laurie4b]

I don't have a heart rate monitor so I don't know. I go for the level that is a challenge but sustainable, not panting but sustained conversation is challenging. The running (and biking for that matter) naturally vary in intensity though with the hills.

 

 

I don't have a heart rate monitor either. You just need a phone or a watch or something with a second hand. At a couple points of your walk (or you can stop your bike), stop for 10 seconds and count your heart rate, then multiply by 6. It's easiest to pick it up on your carotid artery. Don't press with any firmness though because it elicits a response that will slow down your heart rate. You will of course vary in rate. But I often take mine on a flat stretch, at the top of a hill, etc. so I get an idea of the general range. The perceived exertion scale is good, too, but if you are really wanting to know what it is that is now helping your blood sugar, I'd suggest the heart rate because it may be more at one end or the other. 

[Rosie_0801]

Fasting levels- do you eat supper?

 

When I had gestational diabetes, any exercise above a gentle walk sent my blood sugar levels rocketing because it was a form of stress.

[Soror]

Yes, I eat supper :) I've tried timing supper at various times still ending up with elevated fasting levels. It seems I'm the opposite IRT to intensity of exercise.