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Exercising before a fasting blood test?

Hi,

I just recently had a fasting blood test. That morning, about 3 hours before the test, I engaged in a 25 minute jog ( 5.5mph, as I do nearly every morning). Unfortunately, no one had informed me that I should abstain from exercise prior to bloodwork like this. So I'm wondering, how would exercise affect my results?

Of particular (though not exclusive) interest are the following:
-> Triglycerides (Total was 39. Normally it's around 50 for me, so this is an obvious improvement.)
-> Glucose (Total was 88. Last test done was 2 years ago, and was 79)
-----> Regarding the glucose: would the amounts be higher (due to the liver releasing sugars into the blood) or lower (due to the body's insulin response)?

I'm 32, 6'0, 220lbs. I have also started juicing a lot lately (over the past month), mostly vegetable juices flavored with apples and a lemon.

My biggest concern is insulin sensitivity: 2 years (and about 15lbs) ago I was diagnosed with flatline hypoglycemia (Results: Fasting: 79; 1hr: 81; 2hr: 71). I've since been working towards improving my insulin sensitivity.

Can I generally trust the result that I received (ie, it's under 99, so I'm OK), or was this blood test way skewed due to the exercise? Should I re-test?
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Avatar universal
Exercising in a fasted state is actually smart.

Think about it from an evolutionary standpoint.  If you're an animal or a human living in a primal state, without access to supermarkets or refrigerated food, you go out to hunt or forage not when you've just eaten, but when you're hungry.

Intermittent Fasting (IF) is an approach to fitness which works well for many people.  I've fasted for 18-36 hours, twice a week, and waited until the end of that fast to do 20-30 minutes of high-intensity strength/interval workouts.  I do not do aerobic exercises, like running, as those can be counter-productive to dieting (increasing appetite) and don't increase muscle mass.  Increased muscles improves metabolism as they burn more calories, by weight.

I have skipped the workout when I don't feel up to it, but nearly all of the time, I do just fine lifting weights, doing lunges and sprints, without eating for about a day beforehand.  In a fasted state, the body kicks into high gear, burning fat like crazy.
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Avatar universal
Last time I took a fasting glucose it was 99. Since then I've lost 20 lbs, started exercising, and eating super healthy (lots of fruits, veggies, protein, and healthy fats). And my most recent fasting glucose was 101! How can this be? I exercised about 1.5 hours before the test for an hour and it was very intense weight lifting. I hope the weight lifting is what caused that or else I am going on medication because I am doing everything anyone could do eating and activity wise. :(
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Avatar universal
The percentage points varies to each individual!
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Avatar universal
Actually, that's how I do it every morning, taking a jog (usually 30 mins to 1 hr) before breakfast. On this particularity morning the run was as normal (a bit slower, actually), and for about 20 minutes. It was approximately 3 hours before the test. (Run ended at 6:45, test took place around 10am.)

Gymdandee
I had read that study as well, but what I wanted to know is, more specifically, approximately how many percentage (or total) points of a drop or rise are we talking about?

I doubt the result were too heavily affected either way (ie, I doubt I'm a diabetic, or even pre-diabetic) so I won't worry too much about it, and remember this for next time. If I find I keep thinking about it I'll pick up a cheap glucose monitor and test myself. No need to have the lab redo the test just for this.
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Avatar universal
The University of Michigan Health System advises that exercise can result in either an increase or a decrease in blood sugar levels. During exercise, insulin becomes more efficient. This effect can persist, lowering blood sugar levels for hours afterward. An hour of afternoon exercise may lower glucose levels until the next morning, affecting the fasting blood sugar test. Exercise can also affect glucose levels by releasing adrenaline. This raises blood sugar temporarily. Physical exertion or other activities that cause excitement may increase fasting sugar levels if performed shortly before the test.


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1829282 tn?1325591658
I'm confused how exercise can have an affect on a blood test... explain?

I thought this thread was going to be something along the lines of... should I exercise because I haven't eaten anything since the day before... not smart, btw.
Helpful - 0
1 Comments
I read your comment I've been messing with high glucose for bout 5 years. Dr. has me on meds and finally said if your readings stay high we need to start shots of insulin. I got me really thinking, Bout the same time I injured my back with 2 crushed discs, or about 7 months later I started getting high readings. I figured it was from no exercise My job was physically demanding 8 hrs.' a day so I never had to lift weights. I looked around the house and the yard n found suitable scrap metal 10lbs to start an just started doing curls n n presses with different weight. Also started 1/4 knee bends until I could do deep knee bends after a month Calf raises things like that. Now a two months later my readings are much better, for instance after a meal say Lunch my reading was 155 . I did light weight Bicep curls 4 sets high reps Then did knee bends and calf raises also some curls for the back of my legs. I did it all in 20 Min. sat down an rested 10 min. took a reading an it was 93. 1/2 hr later it was 82. and I took no meds that day. Basically you need to experiment in the morning an see if this light weight high rep. will bring yours down. it works for me. thanks

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