Exercise and fasting blood tests

[Joni O]

My doc told me exercise affects blood glucose levels and not to exercise before a blood test.

[Nuggie's Auntie]

Originally Posted by bolieikl

I used to always exercise before my bloodwork. I found out that it is not advised. My GFR showed came out low, which indicated Stage 3 kidney disease and my potassium was high. After repeated testing and being scared to death, I was told by a Nephrologist that when I ran and did weights, it caused my creatinine to raise (which would make me GFR be low) and the plyo moves and running can raise my potassium. I thought I was drinking enough water and that it would flush it out....but I guess not enough time passed between the workout and the blood draw. The doctor told me to always take a day off (or two) before my blood work. They redid the blood work a few times and did several tests before we realized what was really going on. All is well ....but there were several months of being scared for no reason.

I know a lot of people probably are able to work out beforehand and be okay....but that was my experience. My workouts were two hour workouts.

Linda

Oh wow, that's scary! Your workouts sound pretty long/intense... maybe they don't think to advise people to abstain because so few people exercise like that? I don't know, but you'd think they'd caution people against it anyway, just in case.

As someone mentioned upthread, I can see it affecting glucose--all the glycogen stores are tapped to fuel the exertion. But I wonder what the threshold is...

[Usia]

Originally Posted by Joni O

My doc told me exercise affects blood glucose levels and not to exercise before a blood test.

Interesting. My previous PCP who knew very well that I exercise almost every day has never mentioned not to work out before I have my blood drawn.

I'm having my annual physical with blood work this Wednesday before work (new PCP - the old one retired) and I guess it's just as well that the appointment is at the crack of dawn and I won't have the time to get my workout in before I have to be there. I'll ask the new PCP about this.

[Erica H.]

Well, I called my doctor's office and was told that it's fine to exercise before the lab work. I think that's wrong, though. I'd love to do it just because it's more convenient for me, but I don't want to pay for inaccurate results.

Erica

[bolieikl]

Originally Posted by Nuggie's Auntie

Oh wow, that's scary! Your workouts sound pretty long/intense... maybe they don't think to advise people to abstain because so few people exercise like that? I don't know, but you'd think they'd caution people against it anyway, just in case.

As someone mentioned upthread, I can see it affecting glucose--all the glycogen stores are tapped to fuel the exertion. But I wonder what the threshold is...

Yes, it was scary 😞 I was training for a Marathon and ran and then did my STS or Gym Style weights.'(actually I did the weight work and then went directly into running) But I did it for years and never thought a thing about it.

[Erica H.]

Originally Posted by bolieikl

Yes, it was scary 😞 I was training for a Marathon and ran and then did my STS or Gym Style weights.'(actually I did the weight work and then went directly into running) But I did it for years and never thought a thing about it.

This is pretty much how I exercise, but I run first and then lift. My original plan was to run, get the blood work done, and then come home and lift.

Erica

[bolieikl]

Originally Posted by Erica H.

This is pretty much how I exercise, but I run first and then lift. My original plan was to run, get the blood work done, and then come home and lift.

Erica

I hope it all turns out ok😄 I know a of of people exercise and it is ok. But I think I will do it afterwards from now on. 😄

[Sophie]

Originally Posted by Erica H.

Well, I called my doctor's office and was told that it's fine to exercise before the lab work. I think that's wrong, though. I'd love to do it just because it's more convenient for me, but I don't want to pay for inaccurate results.

Interesting. Maybe they are measuring something that is unaffected by exercise, or they're assuming that you won't be exercising long or intensely enough to influence the results. It is a little weird.

[Erica H.]

Originally Posted by Sophie

Interesting. Maybe they are measuring something that is unaffected by exercise, or they're assuming that you won't be exercising long or intensely enough to influence the results. It is a little weird.

I have a lot of tests ordered and, from what I've read online, many could be affected by working out before blood is drawn. Getting this answer from the office makes me doubt their professional advice (I am already wary of most doctors).

Erica

[videofit]

I don't exercise before or after the day I have blood drawn. Just use it as a rest day.