AskNadia: Is It Bad If My Blood Sugar Goes Up After Exercise

Dear Nadia:

 I’m 56 and underwent bypass surgery four months ago. Normally, in the early morning, I check my blood sugar level. It shows an A1c as low as 4.0% (68 mg/dL) and up to 5.5% (111 mg/dL.) But after doing exercise, my blood level goes up to 6.3% (134 mg/dL). Is this good or bad? I’m on medication.


Dear Katherasan:

Your question is one that comes up frequently. How is it that vigorous exercise can actually increase your blood sugar levels? Shouldn’t it do the opposite and lower them because of all the glucose your body is burning?

The answer to your  question requires more information than you’ve given me:

What type of exercise are you doing? Mild, such as walking, or hard, such as weights or running up stairs?

How about the intensity, and duration of your exercise?

Do you have  high blood sugar numbers an hour or two after exercising?

Are you consuming quick, easily assimilated carbohydrates to bring your sugar levels up just before exercising? If so, that could be one reason why your level ratchets up to 134 mg/dL despite exercise.

A reading of 134 mg/dL is equivalent to an A1c of  6.3%. This figure is below the 6.5% to 7.0% that the American Diabetes Association recommends as a normal target range.

Dr Richard Bernstein, an advocate of tight control and a  low carbohydrate pioneer, will argue that your A1C should be below 6.0.

Why Exercise Can Increase BG Levels

One of the most important recommendations physicians and endocrinologists offer people with diabetes is to exercise. Generally speaking, there are two factors that may be at work in your situation:

  1. The amount of insulin in your system, whether from your own pancreas or from an external source, may be low to start. Exercise may “burn” off blood sugar but not be enough of a burn to assist what insulin you have.
  1. Intense exercise, such as sports or weightlifting, can make the body release stress hormones that force the liver to release more glucose. Combined with a low level of insulin, the effects of exercise-induced stress can make blood sugar levels increase.

To fine tune your blood sugars when exercising, make an appointment with your healthcare professional and have the answers to some of these questions. This way they can assist you in adjusting your medications and advice you an achieving your desired blood sugar post exercise.



Nadia’s feedback on your question is in no way intended to initiate or replace your healthcare professional’s therapy or advice. Please check in with your medical team to discuss your diabetes management concerns.

View Nadia’s Videos 

 About Nadia:

Nadia was not only born into a family with diabetes but also married into one. She was propelled at a young age into “caretaker mode,” and with her knowledge of the scarcity of resources, support, and understanding for people with diabetes, co-founded Diabetes Interview now Diabetes Health magazine.

Nadia has received 14 nominations for her work as a diabetes advocate.
Her passion for working in the diabetes community stemmed from her personal loss of family members to diabetes. She has used her experience as a caretaker to forge a career in helping others.

Nadia has been featured on ABC, NBC, CBS, and other major cable networks. Her publications, medical supply business, and website have been cited, recognized, or published in the San Francisco Chronicle, The Wall Street Journal, the Ann Landers advice column, former Chrysler chairman Lee Iacocca, Entrepreneur magazine, Houston News,, Brand Week, Drug Topics, and many other media outlets.





Leave a Reply

Your email address will not be published.