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Effects of exercise on glucose readings

I'm a female, 60 years old, with type II diabetes, taking 1000mg of metformin daily and have been exercising regularly for well over two years.  My glucose is well under control (I thought), with A1C readings between 5 and 5.5 for the last two years.  Recently I had reason to wonder about my glucose levels after exercising.  I exercise twice a day; early in the AM before work and after work.  I usually do a 45 minute routine on the treadmill or a combination of treadmill, bike or resistance.  I have found over the last several weeks that my glucose levels rise after exercise in the AM (I workout before eating), usually as much as 30-40 points (from 103 to 145 for instance).  In the afternoon, my glucose levels usually fall between 20 - 25 points.  Any ideas about what's going on?  I do have an appointment with my doc in a couple of weeks and will talk with him, too, but I thought I'd try you out.  Thanks!
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Avatar universal
Since I posted the question, not only did my glucose readings go higher than usual in the morning, I began to sweat profusely when I walked and I was finding the whole exercise routine difficult.  I was really fighting to continue through to the end and running way short of breath.  I finally went to my doc (before my scheduled appointment), and found I had a deep respiratory infection.  Now with antibiotics and a prednisone burst, I'm back doing what I've been doing and feeling great.  My glucose levels are down in the AM like always, and while the exercise isn't easy, it feels good.  I've lost a lot of weight in the last two years and I guess I'm just now finding out what being sick in my new configuration is like.  Thanks for the advice and ideas.  Thought I'd better let you know it was a bug!
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Avatar universal
YOu're right, SS.

We shouldn't exercise when our BG is over 225ish because the inadequate insulin onboard will cause a cycle that raises BGs.

It goes soemthing like this.  With a high BG, our muscles are starving for the fuel that's floating in our blood stream.  The muscles, if exercised, call for more fuel.  THe liver responds by dumping glucose into the blood strea, *intending* it to get to the starving muscle cells.  But, alas, ... there's not enuf insulin onboard to deliver the sugar to the cells and so the liver-dumped sugar just stays in our blood .. raising out BG.  The muscles are STILL starving and so they call for more fuel and the cycle repeats.

If our BG is 225+, it's much better to wait 'til it drops below 200 (due to taking more insulin or waiting 'til the insulin on board peaks) and then prepare for exercise.
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Avatar universal
We're not physicians heres, so please do discuss what you read here with your doc when your appt time arrives.  We are experienced with Type 1 diabetes.  I have read a bit about Type 2 and might be able to shed some light on what's going on.

First, it's terrific, super, and great (!) that you're so well committed to your health. YOu've achieved excellent a1c and your dedication to exercise helps in that regard.

Many diabetics, including type 2s, experience a "Dawn Phenomenon" -- it doesn't have to happen at dawn, but it does occur in the morning.  As our bodies ready themselves to sieze the day, hormones are released that raise our blood sugar.  I have read that Type 2s can dampen that phenomemn by having a small snack that has protein and long-acting carbos before bedtime.  APparently, the effect is that blood glucose levels are kept above "the point" at which the liver will dump glucose into the bloodstream to raise it.  "the point" is not something I know and I don't know if anyone does.  On another board, I read several reports that this technique prevented their early morning highs.

In your case, you wake up with a great number, and in your exercising your body is burning whatever carbos are available in the your system.  Then, your liver will dump some more glucose to help you thru.  I'm not a physician, but that's my best guess of what's going on.  If I began exercise with a BG of 100 I would have to have some food on board, or I'd crash with a severe low (I take insuiln).  Check with your doc about taking a small snack (part of your breakfast, not in addition to) with protein & complex carbo before you begin your exercise.  I would expect your BG to remain fairly stable in the morning.

Normally, we expect exercise to lower our BG as you experience in your late date routine (no dawn phenomenon at play).  If the drop seems too much, then chat with your doc about taking a small snack (protein & carbo) to level out your results then, too.

Do let us know how this turns out.  Your numbers & your commitment are an inspiration!
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Avatar universal
Hello  jmrommes,

I am not a medical professional, so my advice / input is based on personal experience from taking care of my 10 yr. old son who was dx with type 1 at the age of 3.

Do you test your BG in the morning before you workout?

Everything I have heard / read mentions that exercise lowers the blood sugar, however, I have also heard that for some that isn't the case.  I have heard that if your BG is over a certain # (cannot remember if it is 250 or 300 - feel free to chime in anyone and correct me:) and then you exercise, for some it will raise the BG even higher.  It is good to keep a note of what it does for you.  (as you are)  For my son, exercise / physical activity lowers his BG.

It is good that you are seeing your doc in a couple of weeks and do talk to him about this.

Your A1C is GREAT!  Good JOB!  You sound like you are on the right track.
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