[EllieK]

My blood sugar goes up when I exercise. Sometimes up to 170 or 180. Does anyone else have this difficulty? and what to do if anything? If I walk for about 2 hours it will finally drop.
But usually I walk 45 to 60 min in morning before I eat and 30 to 40 min most evenings. Any ideas?

[Ronin]

Hi Ellie!

Blame your liver, and possibly your form of exercise. I noted from your pubic profile that you are on what you call "an extremly low carb diet." That may be part of the problem if you engage in hard aerobic or anerobic exercise. The reason is that your BG levels are not sufficient to cover the energy needs of your body. Therfore your liver dispenses a large quantity of stored glucose (oh yes, your liver is capable of manufacturing glucose so even the low carb diet can be defeated by your liver). As I understand the mechanism, that "burn" from your muscles is a signal to your system that it desperately needs glucose and as long as it is in your blood stream you liver will deliver. (FWIW: I have a similar problem because I am a very aggressive bicyclist/tandemist. My almost daily rides are longer than 90 minutes and often take me into the "Red Zone" with scads of lactic acid burn. My BG spikes as a result, albeit not above 140 so far. I share your problem in spades.)

I do have a question for you: what is your C-Peptide level? I'm personally finding more-and-more Type-2's who have low to no C-Peptide readings. These people respond well to insulin because their pancreas isn't producing sufficient insulin to use the glucose. You may find you are a Type-1.5. (Personal experience: My fasting C-Peptide is right on the border of below-normal but just on the normal side. While I can handle carbs and my body does respond to the insulin produced, it does so much more slowly than a non-diabetic.)

The long walk will draw down the BG levels because it is not as intense and allows your body to use the available glucose without screaming for more.

[xMenace]

Originally Posted by EllieK

My blood sugar goes up when I exercise. Sometimes up to 170 or 180. Does anyone else have this difficulty? and what to do if anything? If I walk for about 2 hours it will finally drop.
But usually I walk 45 to 60 min in morning before I eat and 30 to 40 min most evenings. Any ideas?

Sounds like there's no intense exercise. Try eating first then go for your walk. Consuming food will cause a release of insulin. By not eating, I suspect your body is becoming defensive and your liver is dumping sugar.

[REDLAN]

You don't specify after what kinds of exercise that your BG rises.

Is it after the walk in the morning and in the evening? Or one more than the other? Is one of greater intensity than the other.

Suggestions (in addition to Ronin's excellent points)

1) high intensity exercise can raise BG - because as Ronin points out that the body's response to lactate is to stimulate the liver to increase cycling of lactate (turning it back into glucose which is released back into the bloodstream), and to increase the rate the liver breaks down glycogen into glucose, which is released into the blood stream. This effect can be quite extreme - I personally have experienced a BG that reached 360 (20mmol/l) just from the effects of intensive exercise.

the answer is, to lower the intensity of the exercise - ensure that you stay in the aerobic zone. The muscles respond to exercise by becoming more sensitive to insulin. This benefit will occur with relatively gentle exercise, such as the 2 hour walk you mentioned.

Another thing to look at is the timing of the exercise - particularly the walk in the morning. Type 2 is characterised by a loss of flexibility in the ability of the body to alter insulin resistance. A normal individual after fasting will have relatively high insulin resistance - this is to preserve glucose for important tissues, and to force the body to use fat as the primary fuel. As soon as they eat, the insulin resistance of the peripheral tissues, particularly muscle, drops, to allow them to absorb the recently digested glucose. In type 2 this response is blunted.

suggestion - exercise after you eat in the morning. With exercising before, you are relatively insulin resistant - if you exercise hard, then your relatively insulin resistant muscles will not be able to properly absorb all the glucose being dumped by the liver. If you eat before, the act of eating should help to lower the insulin resistance of your muscles, and enable them to take up glucose more readily.

[BrianSCohen]

I too suffer from blood sugar rises with hard exercise. More moderate exercise burns off my blood sugar and keeps me low. After adaptation to very low carb, you should not suffer from wild swings in blood sugar during moderate exercise, you should be ketogenic and adapted to burning fat. I would suggest that if you are power walking, 4-5 mph, that you try doing that in either at the begining of your workout or in intervals. End your workout with 15-20 minutes of gentle walking to bring your blood sugar down.

Exercise can really improve your insulin sensitivity, and it is for this reason that it is good to time your exercise to before a meal/snack. I try to have a meal/snack after my workout. Often it is the only carb of measurable quantity that I consume.

[EllieK]

Thank you for all the feedback. I have wayyyyy too much insulin in my body. My pancreas just keeps producing much for than I need which is why I do the low carb to try and get it to back off, and never eat more than 300 cal. at a time.
I do moderate walking with intervals of speed. I try to go to the gym a couple times a week just to shake things up.
I will let you know if eating before hand works.
Thanks again!

[BlueSky]

high intensity exercise can raise BG - because as Ronin points out that the body's response to lactate is to stimulate the liver to increase cycling of lactate (turning it back into glucose which is released back into the bloodstream), and to increase the rate the liver breaks down glycogen into glucose, which is released into the blood stream.

I know this happens when the body is pushed to the limit. But would it happen when walking? EllieK walks for 45-60 minutes. It doesn't sound like this exercise is anywhere near being anaerobic.

[REDLAN]

I know this happens when the body is pushed to the limit. But would it happen when walking? EllieK walks for 45-60 minutes. It doesn't sound like this exercise is anywhere near being anaerobic.

It depends purely on the intensity of the exercise. Walking can be intense enough to produce high enough heart rates.

Traditionally the lactate threshold is the point at which Lactate begins accumulating in the blood - for ordinary people (not athletes) this can be as low as 60% of MHR. But rates around 70% are not unusual for the averagely fit person.

The interest in finding out where the lactate threshold is for an athlete, is because it determines the maximum performance he/she can maintain without fatigue.

What matters for us is not strictly the lacate threshold, but the intensity at which lactate is produced by the muscles - as lactate will stimulate the liver to recycle the lacate back into glucose, and release glucose from glycogen. This can then be a problem if you experience insulin resistance - rising BG from moderate exercise.

I can happily produce a heart rate of around 150 bpm with a fast paced walk up a hill - that's around 70% of my MHR, enough to stimulate lactate recycling, and break down of glycogen by the liver. For me it's not a problem, because I'm insulin sensitive, and my BG tends to drop rather than rise.

[shutterbug]

For me it has gone both ways. When I exercise 1 or 2 hrs after a meal, mine goes up to 120-130. When I do it before the meal I don't see any increase more than my usual PP reading.

I'm not sure if this helps

[kstreeter513]

I run pretty regularly. And it never fails that when I run a 5k, my BG always soars to levels of 250-300. Im still trying to work out the insulin issues, but the last thing I want to do during a race is get a hypo. A 5k is a fast race. Im red-lining the whole thing, so the liver metabolizing the lactate thing makes sense.

[jen_slc]

Yes, my BG goes super high with extremely intense exercise. After an hour of a dance/cardio class, my BG goes up from ~100 to anywhere between 300-400. Doesn't feel so good. I've found that 1u of rapid insulin prior to working out prevents the spike.

My workouts are after work at the end of the day, and if I'm hungry, I will have a little snack and cover it with ~1/2 of the insulin I would normally use, and that usually keeps me from spiking too.

[Ronin]

EllieK, et al.,

I did and experiment this morning. My FBG was 94, my two hour post-breakfast reading was 91 (Breakfast: 3-Egg White omlette with Turkey ham and FF-cheese, one slice of The Baker Whole Grain Bran toast, coffee, and 1/4 cup of OJ). Then Linda and I went out on our morning tandem ride of 22 miles which we completed in 1:19:11 rolling time (avg about 16 mph). When we got back I checked my BG levels (something that I don't do often) and it was 136.

The question is: where did all that glucose come from? Breakfast was digested, nothing except water during the ride, so where-oh-where did the glucose come from?

My only guess is that my "Liver delivered" the glucose needed to power the muscles during the ride and kept it at an exercise level.

Can/does exercise increase BG levels? Yeah, it does. The good news is that exercise increases the insulin sensitivity so that whatever insulin your body produces (apologies to the Type-1's who don't procuce any insulin) works better.

Okay, this is a one-off experiment, but my sense is that this is what happens to me all of the time. It may also happen to others.

[REDLAN]

The question is: where did all that glucose come from? Breakfast was digested, nothing except water during the ride, so where-oh-where did the glucose come from?

This is my take on that one

1) once you go above a particular threshold of effort, your fast twitch muscles will start to kick in to provide the extra power. These muscles mostly burn glucose anaerobically, and the byproduct of this is lactate, which is dumped into the blood stream. Your liver responds by turning the lactate back into glucose and releasing it into the blood stream. This glucose is then absorbed by the muscles. So one source of glucose is muscle glycogen.

2) the body's response to exercise is to release a variety of hormones including catecholamines (stress hormones). These hormones typically counter the effects of insulin. In the liver they stimulate the breakdown of glycogen into glucose. The so called liver dump, and is your second source of glucose.

3) If you exercise for long enough and hard enough, you can leave your muscle cells low in stored glycogen and fats. The muscles respond to low energy levels (in this case high concentrations of AMP) by manufacturing more glucose transporters, making them markedly more sensitive to insulin. The onset of this effect is relatively slow, and tends to take place in the hours after exercise has finished

In someone with insulin resistance, effects 1 and 2 can become quite a problem. Glucose is dumped into the bloodstream, but high insulin resistance slows absorption by the muscles, so it builds up in the bloodstream - aka the high blood sugar of exercise. Effect 3) peaks several hours later, so doesn't help until after the exercise has finished.

[BlueSky]

Originally Posted by Ronin

... The question is: where did all that glucose come from? Breakfast was digested, nothing except water during the ride, so where-oh-where did the glucose come from?....

Ronin,

It is also useful to see the quantity of glucose in your blood stream in perspective. At normal levels, there is about a teaspoonful of glucose dissolved into our 5 litres of blood. That isn't much. So when your blood glucose went up by 45% (from 94 to 136), that represented about an extra half a tespoonful of glucose. That is about 2.5 grams of glucose, or 10 calories worth. The amount is tiny in relation to all the glucose you burned up during your ride. If you used, say, 1,000 calories during your ride and 50% of that was from glucose (500 calories), the extra glucose in your bloodstream represents less than 2% of your glucose consumption.

I don't know if my maths are right here, but the amount of glucose in your bloodstream is relatively small anyway. Your BG went up because glucose wasn't being used/stored quite as quickly as it was being created.

[Ronin]

Redlan, Blue Sky, et al.,

Interesting. I kind of knew how this works, but not in so much detail. I also know the reality of our tandem rides, we are not casual cyclists -- we ride hard most of the time and actually have to force ourselves to "take-it-easy" some days. I know that I will have depleted what little energy is flowing in my bloodstream pretty fast and then shift into using the reserves. For longer rides (over 25 miles) I do have the practice of eating something every 10 miles so that I have a continuing supply of energy. When I finish the ride I know I am depleted and working off the stored energy in my liver for upwards of an hour following the ride.

What was most interesting was the calculations of how much glucose is actually flowing -- when we think about it, it isn't all that much. I now realize that the human engine is pretty darned efficient even though a lot of that energy is wasted as heat. No wonder the bicycle is considered to be the most efficient machine invented by humans.

The 1000 calorie number for that particular ride is probably close to my actual consumption, albeit I'm probably using more like 1200+ due to terrain and speed. The output is usually a bit lower when I ride my single bike on the same routes.

As to the issue of Insulin Resistance, that is a problem that I don't have (thankfully) and largely due to my exercise. The great news for everyone is that it works regardless of age or general condition -- I've heard a lot about how many people would not have a problem if the did even moderate exercise on a regular basis.

I do think that we have answered EllieK's question quite well.