Fasting Blood Sugar

Schlep · #1 (**permalink**) 01-18-2008, 06:18 AM

I have to go in for a blood test and as usual have to have nothing to eat after 12 pm.

My question is can I get the test after I do my walk or does it have to be before my exercise, as the numbers do change.

During my walk I may hav a couple gulps of plain water. I have nothing to eat before my walk.

Thanks

princesslinda · #2 (**permalink**) 01-18-2008, 06:34 AM

In my opinion since your numbers may tend to rise after exercise (at least for a little while afterwards), i'd get the blood drawn first, for the most accurate fasting reading.

Schlep · #3 (**permalink**) 01-18-2008, 06:42 AM

Quote:

Originally Posted by princesslinda

In my opinion since your numbers may tend to rise after exercise (at least for a little while afterwards), i'd get the blood drawn first, for the most accurate fasting reading.

Linda when I started my exercise routine the numbers did rise but now that the routine is more intense the numbers are dropping by at least 1 point after exercise.

princesslinda · #4 (**permalink**) 01-18-2008, 06:46 AM

Looked up "what can affect results of fasting glucose test"....

The Fasting Plasma Glucose Test - Understanding the Fasting Plasma Glucose Test

"What Can Affect Test Results?
Results may vary from lab to lab, or -- in the same lab -- from day to day. As a result, two abnormal results from tests taken on two different days are required to confirm a diagnosis.
Results may be lower if blood is drawn in the afternoon rather than in the morning. And a glucose level sometimes can be “falsely low” if too much time passes between when the blood is drawn and the lab processes the sample. The results can also be affected by previous or current medical conditions or by personal habits, such as smoking and exercise. "

When i'm having lab work drawn that has to be fasting, I fast x 12 hrs, no water or anything until after the blood has been drawn.

Schlep · #5 (**permalink**) 01-18-2008, 06:50 AM

Thanks Linda I appreciate the time you spent looking for that. Just a n FYI I just got off the phone with my doctor and he said to keep to my ususal routine and it does not matter if the test is before or after exercise.

Thanks again Linda as I did not think I would be able to get an answer that quick from the doctor, he must have been sitting beside the nurse having coffee.

DCaplinger · #6 (**permalink**) 01-18-2008, 06:56 AM

Absolutely have the blood drawn BEFORE any exercise! Exercise can cause brief increases in BGLs, or it may cause sudden decreases in them.

Regards,

princesslinda · #7 (**permalink**) 01-18-2008, 07:10 AM

Quote:

Originally Posted by Schlep

Thanks Linda I appreciate the time you spent looking for that. Just a n FYI I just got off the phone with my doctor and he said to keep to my ususal routine and it does not matter if the test is before or after exercise.

Thanks again Linda as I did not think I would be able to get an answer that quick from the doctor, he must have been sitting beside the nurse having coffee.

Glad you got in touch with your doc so soon Schlep...thanks for sharing his information with us. Interesting how different doctors want different things...I find that to be true in the practice I work in...5 doctors, 5 opinions on the best way to do things. Let us know your results.

DCaplinger · #8 (**permalink**) 01-18-2008, 09:06 AM

WAIT! I cannot believe what I just heard. Is that doctor an Endo? If not, IGNORE what you were told!!! The doctor is deadpan wrong.

When I worked at the clinic, we had to ask 2 questions to diabetics before we did their draws:

1) Have you fasted for at least 8 hours prior to this test, eating nothing at all, and only drinking clear fluids or coffee?

2) Have you performed any exercise in the past 4 hours?

If the answer was yes to #1, and no to #2, we could do the test. If #1 was no or #2 was yes, we had to get permission from the doctor first, and that was usually denied.

I would strongly suggest getting a second opinion on that before having a test done.

Regards,

morrisma · #9 (**permalink**) 01-18-2008, 09:56 AM

Might be just as important to do it the same way each time - either before or after but not both.

Read somewhere that students who studied while drinking did better on tests when they'd had some alcohol before the test as well. Explains a lot of MY college career

I'd tend to go with the before exercise since that has the fewest variables and best repeatability for comparing future results.
Mike