High blood sugar levels after exercise

By PRP Latest Reply 2010-06-21 13:20:06 -0500
Started 2010-06-01 13:29:02 -0500

I am puzzled by my high BS levels after certain high intensity exercises. I researched on the internet and found plausible reasons for this. One being that during high intensity exercises, the body tends to burn fat for energy instead of sugar and so it is normal to have high sugars after the exercise. Now I have a two fold question. The first is whether that explanation is true and second should I stop doing the exercise. I scheduled a doctors appointment in two weeks. In the meantime I don't know whether I should continue or stop.
As for the background, I was diagnosed type 2 about a month and half back. I had fasting BS levels of 150. Since starting on diet and exercise I was able to bring fasting BS levels down to 110 - 120. I am really happy about my weight loss too and don't want to stop exercising even though I know I will get a medical opinion in two weeks (hopefully a correct one). So I wanted to get some input from you all as a community because of the vast amount of experience and knowledge.

Thanks in advance

17 replies

PRP 2010-06-21 13:14:03 -0500 Report

I could not get any satisfactory answers from my doc. She kept saying 100 - 120 is OK. I personally think that 80 - 100 is OK, but that is a different story. What i wanted guidance from my doc was what kind of exercise I should do and what kind I should not. I had asked the group whether I should see an Endo or a Diabetes Educator to get all these answers. The overwhelming response was that I should see a Diabetes Educator ASAP and see an Endo depending on how the session goes as the Diabetes Educator appointments are easier to get than that of an Endo. So I am planning on seeing the Diabetes Educator in the next two weeks to get as many of my questions answered. I will come back and update this thread on what I learnt. I know most of the people here are very knowledgeable but my answers might help somebody who has the same kind of questions.


UniquelyMe 2010-06-21 07:35:38 -0500 Report

I have the exact opposite problem…my BS drops like a rock after I exert myself. Let me say that I just started 3 shots of Novolin 70/30, and 1 of Novolin R about a week ago. Until then my BS ran in the 300's and the lowest was 200's. Now it drops so fast…If I do my shot then do something that makes me sweat my BS drops fast… I'm new to this so any help would be great…

PRP 2010-06-21 13:20:06 -0500 Report

I learned that that is natural when taking insulin, but I might be wrong. From what I have learned, if you are taking insulin, you are supposed to check you sugar before you exercise and depending on when you took insulin, you might have to eat/consume some carbs to make up for the lows that will result due to the exercise. When you exercise the body uses insulin (whether your own or injected one) much more efficiently and rapidly and this results in reducing the glucose levels faster than in normal conditions. And that's the reason for the snacking advice before exercise.


dyanne 2010-06-21 01:53:16 -0500 Report

I was told once by a dietitian u start to exercise and ur sugars are already a little high it can make them go even higher !! Ask your Dr.about this. Good luck

Anonymous 2010-06-20 17:52:10 -0500 Report

PRP by now you have seen your doctor and I hope he has set you on the right path. He no doubt did a pre and postmeal glucose test to get an idea on what your are doing with the excecise. While general advise is great, every diabetic has some little strange reaction to food and excercise. So take what we are telling you with a grain of salt, (not really salt LOL) You know your own body, so work to keep your self fit.
Good luck and long life. Don't stress out so much over this, you control the diabetes, don't let it control you.

Daskylinegal 2010-06-17 13:06:40 -0500 Report

I believe it is best to get the answer from your doctor. I am a type1 diabetic on the insulin pump, everyone has there opinion on what is best, in my opinion, stress & eating foods that raise your sugar causes high readings.
I pray you find the answer!

PRP 2010-06-05 13:06:14 -0500 Report

Update. I thought that the blood sugars are high after high intensity cardio. But after tracking for the past week I am not so sure anymore. I have seen spike of +10 to +15 after both high intensity cardio and lifting weights and also seen -12 to -5 after both types of exercises. So I have stopped trying to figure out what the reason is and will wait for my endocrinologist visit. I will update the thread after what he says.


John Crowley
John CrowleyCA 2010-06-04 12:45:51 -0500 Report

When my diabetic son was playing competitive soccer, he would often see high blood sugar after playing very hard in a soccer game. Our doctor was mystified for the longest time and was convinced that our son was drinking gatorade or something that was causing the spike. But over time, we determined that our son would get such a rush of adrenaline from the competition that it would release the stored sugars in his liver.

Because our son uses insulin, he was able to try to counteract these spikes by taking a little extra insulin right before games would start.

I'm not sure how that solution translates for you. Perhaps you can talk to your doctor about options.

PRP 2010-06-05 13:09:49 -0500 Report

Thanks John. Somewhere I read the same thing and also read that in a high intensity activity the energy is gained by burning fat instead of sugar even though extra glucose is generated for this purpose. One suggestion that was given was that after the high intensity activity, I should continue to do moderate cardio to burn of the extra sugar. Since I don't take insulin I guess I have to do more exercise. I have to ask my doctor next time.

PRP 2010-06-02 12:01:18 -0500 Report

Just checked my levels today. Fasting levels before lifting weights 113 and fasting levels after lifting weights 97. I am surprised and felt really good as my levels have never dipped below 100 (maybe they have , but I have never seen it when I test). So looks like lifting weights seem to be good thing. I will have to figure out how to fit in the high intensity cardio stuff without spiking my levels. I hate to give it up for a moderate cardio over longer period of time because I know I will be bored and will not keep up the regimen. Any ideas?


GabbyPA 2010-06-01 18:19:27 -0500 Report

How much does it raise your levels? When do you test after you exercise? Those are a couple of things to look at.

Another reason you go up instead of down is that your levels start to drop and your body responds by giving you glycogen from your liver. It should get used up in your workout, but if you test right after the workout, it might not have been absorbed into your muscles.

Don't stop exercising, and if the rise is not a bad one, keep striving for your success. You body is probably all new to this as well, since you were just diagnosed. It takes us a while to acclimate to our new habits.

PRP 2010-06-01 19:35:44 -0500 Report

Thanks for the advice, Gaby.
On my lifting weights day it goes down from 110 @ 5:00 AM to 100 @ 6:00 AM on my Tabata cardio days it goes up from 110 to 122- 126. But I think it comes down to approx 125 @ 8:00 AM after breakfast @ 6:00 AM ( cheese sandwich or PBJ sandwich using whole wheat bread) on both days. The reason why I say "I think" is that I just started this in the past 3 to 4 days. As for if the "rise is not bad one", I am kind of lost and that's why I need help. I really don't know which one is a good rise and which one is bad. Is the increase from 110 to 125 a bad one or not? I think I forgot another piece of information that I am not on any medication.
I don't want to give up exercising because I love the results. I have lost a good amount of weight but I am still ways to go before I reach my goal.


GabbyPA 2010-06-01 20:21:43 -0500 Report

Your rise is not that bad. As long as you are staying under 140 you are doing great. I would keep an eye on it and test 30 minutes after your exercise to see the results. Your body will adjust to it all and level out. Then one day you will see it changes and wonder what is different. LOL.

PRP 2010-06-01 22:06:13 -0500 Report

Thank you very much for the prompt reply. I guess I will continue to monitor it until I go see my doctor. I have been seeing my PCP who is internal medicine. I plan to request a referral to an endocrinologist. I have a whole bunch of questions. May be at that time he might clear up a bunch of questions I have. I read the "Diabetes solution" by Dr. Bernstein. It is a good inspirational book but it scared the heck out off me. He talks about keeping the BS levels around 80 to 90 even in diabetics. After reading that book I was kind of scared to notice that my levels are in the 120's. If I read correctly even a short duration of high BS levels is harmful for your body. I would love to reach those level but it is impossible for me to do that because the diet regime he suggests is very very strict low cabo diet with lots of meat. Me being vegetarian it would be impossible to follow that plan. In fact that is one of the main reasons I want to meet an endocrinologist and see where I stand in relation to my pancreatic health and insulin production. Sometimes I do feel like maybe "ignorance is indeed bliss" after reading a bunch of books on diabetes by different authors. Any way I have to see what my endocrinologist will say. After my appointment I might come back and ask whole set of new questions to you all and get feedback and most importantly positive reinforcement that it is not all gloom and doom.
Again thank you very much for the encouraging words and the assurance that the rise in my BS is not all that bad.


GabbyPA 2010-06-02 18:51:10 -0500 Report

I do suppose in a perfect world our levels would stay between 80-90 but that is asking a lot. After a normal person eats, even they have levels that top out around 140. I have not read his book, but I have heard it is very good. Very strict, but good. I worry about too much meat for my kidneys, so I would talk to your endo when you meet.

Ignorance is never really bliss, just dangerous. But it does keep the stress levels down. All you have to do is find what works for you as an individual and chances are it will be a blend of many of the things you learn.

Roy531 2010-06-01 14:42:20 -0500 Report

Try easing up on your exercise some and see if it will make a difference. I walk every night for 90 minutes, walking 3.5 miles, have treadmill, at 2.3 miles a hour and my blood sugars will go down. I will walk for 45 minutes take a short break then finish with another 45 minutes.

PRP 2010-06-01 15:57:37 -0500 Report

Thanks for the reply. I already observed that non intensive workout reduces my BS levels. I lift weights for three alternate days a week(Mon, Wed, Fri) and do high intensity cardio (Tabata Protocol) on the other three days (Tue, wed, sat). I like the Tabata because of its perceived weight loss capabilities. Also it only takes up 4 minutes to complete it. Granted I am completely winded after 4 mins, I still like it because I see it as a maximum return for minimum time spent. I was more concerned about the short term increase in blood sugars due to that exercise. I have not timed how quickly the levels drop. I have to do that on a one of these days to document the rate of fall. As I said, I am more concerned about the effect of regular temporary spike. Physically I feel OK after the exercise (I think) as I don't feel any different that the days I lift weight.

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