Diabetes in Control has a lessons learned section for health professionals. Although we commonly think of exercise that will lower our blood sugars some insulin users find the opposite occurs. This is the case report.
A man with type 1 diabetes started an exercise program to help him manage his early morning highs. He exercised every evening, at which time his glucose levels would drop during and after exercise. Thinking that exercise would lower his early morning highs, he did not take his insulin before exercise. He was surprised to see his glucose would go up after exercise rather than go down….
He discussed this with his endocrinologist who recommended he take a very small amount of fast- or rapid-acting insulin before exercise. His glucose levels did well. He was surprised to see his levels did not get low, nor were they high after exercise anymore. This became his regular regime.
Lesson Learned:
•Even though exercise makes an individual more insulin sensitive, one still needs insulin for muscles to use glucose. Without enough insulin, glucose levels can rise.
•Individuals can and usually do have different insulin needs throughout the day.
•To lower post-exercise highs, start low and go slow to learn the amount of insulin your patient needs. Some need only one unit.
•Check before, during, and after exercise, or better yet, use CGM and track trends.
Anonymous
Copyright © 2015 HIPER, LLC
From Diabetes in Control 27 April 2015
Diabetes Diet 
I had a similar conversation about diabetes and coffee. It tends to make my blood sugar skyrocket, others believe it has no impact at all. I appreciate the thought that we are all the same, yes we are different.
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I am type 1 diabetic with some remaining beta cell function, my doctors put me in the T1 LADA category (but I know certain diabetes experts such as Dr. Bernstein don’t agree on the LADA classification of diabetics).
Anyway, I regularly perform morning exercise before eating breakfast, sometimes at a low intensity (walking, jog, stretching), sometimes at a high intensity (weightlifting, interval sprinting). I also noticed the same effect on the BG levels when I performed high intensity exercise. I would start out with a normal BG in the range of 5-6mmol and straight after the exercise the BG level is much higher, even as high as 10+mmol depending on the intensity. It seems to go highest when I do interval sprinting.
I believe Dr. Bernstein suggests that you take a small dose of insulin before high intensity exercise to counteract this BG rise. However, I worry if I took even a small amount of insulin before a high intensity workout that my BG would go too low. The reason I say this is that even though my BG initially goes up to say 10mmol for example straight after my workout, it rapidly comes back down within the normal range and it is not unusual for it to go below 4.0mmol without any insulin an hour or so after the workout. The beauty of this type of exercise I find is that it also helps keep the BG levels lower throughout the remainder of the day. Also, for me this increase and then reduction in BG from high intensity exercise occurs after each session, no matter what time of day. The only thing that I have noticed is that perhaps the rise is not so high when I perform this type of workout in the afternoon or in the evening, and I believe that this is because I have a higher insulin sensitivity in the afternoon & evening.
With low intensity exercise I never experience this affect, it does seems help keep my BG in check (together with low carb eating of course), but it definitely does not provide the same prolonged BG lowering effect that I get from high intensity type workouts.
Love the blog!
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Hi there Edward, thanks for taking the time to comment and share your experiences. I’ve always found that high-intensity exercise can send my blood sugar levels soaring, but I’ve never paid as much attention to the overall, longer term effects the way you have. (I should, really.) I think we all respond differently. Like you, I’m more sensitive to insulin in the afternoon/evening. I rarely feel like exercising in the morning, though… Anyway, thanks again for sharing. It seems as if you are managing your diabetes very well indeed.
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Thanks Emma. Blogs like yours, Diet Doctor, Dr. Bernstein’s book and you tube videos and Jimmy Moore’s podcast show help me a lot!
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That’s what we are here for. Thank you!
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