Blood test before or after working out, or does it not matter?

[Clyde]

Hello. I need to go for my annual physical and in the week before, I go for a blood test. Does it make a difference if I work out immediately before? Or does it not matter? Also, I thought I read somewhere that lifters' blood results sometimes show high levels of [??], but I don't recall what it is. Does anyone know if any lifters' metrics are habitually "off" so I can let the doctor know? For the record, my doctor does not look like he lifts, nor does he have razor abz.

[Mark Rippetoe]

CPK. It will be higher.

[Fulcrum]

Depending on how hard you workout and whatnot, I've read your test.levels might be a bit lower.
(might peak a bit immediately after/during strength training, then drops after that)

Heart rate might be still elevated just a tad more than normal (once again, depending how hard you workout)

I would probably schedule on a day off from lifting;
for blood work you normally fast and have blood drawn first thing AM.
I aint lifting fasted and then sitting in a Dr's office. No way. Not me. Nope.

And just say that I did do that, I would be one irritable guy that morning.
Probably score some higher BP and whatnot.

- not a doctor

[Jr_Geezer]

Do you take creatine? If you’ve been taking it for a while, your creatinine levels will be elevated, which the doctor might evaluate as kidney problems.

[Jr_Geezer]

Obviously I should have looked up CPK before posting.

[ColoWayno]

They don’t care about T levels. They might say your liver is going to explode if you get tested up to 10 days after lifting heavy.

[jfsully]

CPK (or CK) will be elevated for a little while after lifting, but that would not be routinely tested, unless you have a boutique doctor who likes to do “all the tests” to convince patients they are getting their money’s worth and a “thorough” evaluation. It may be as high as low triple digits, and if your doctor calls you with concern about it, they should be reassured when you say you were lifting heavy the day before. If your CK is in the thousands, though, don’t blow that off.

The typical “liver tests”, ALT and AST, might be a little elevated from lifting heavy too, from muscle breakdown (not from liver damage). If they are just out of range, probably fine. If they are in the 3-4 digit range, you have a problem, probably in your liver, unless you were run over by a bus the day before and have massive muscle breakdown. In which case you have a different problem.

Creatinine (Cr) is different from CPK/CK, and is pretty much checked whenever routine blood tests are done. It is used to estimate kidney function. Higher than expected creatinine in the blood suggests to your doctor that your kidneys may not be filtering properly. Creatinine in your blood is there as part of muscle turnover, and is filtered out by the kidney. Creatine that you take as a supplement is metabolized into creatinine, so you might have higher blood creatinine than normal, since the “normal” ranges were normed on people who get creatine from food only and don’t supplement. If your doctor is alarmed by a high creatinine level, they may or may not be reassured when you tell them you take creatine. They may not know what that means, and/or they may be under the misapprehension that taking creatine or protein supplements is bad for the kidneys, and THAT is why your Cr is elevated (this has been studied to death and is not a concern). If your creatine (Cr) is like 1.2, that’s probably fine and from creatine and above average LBM. If your creatinine is 3 or more, that’s not good no matter what supplements you are taking. Also, remember, you might have kidney disease someday, and it would be a bummer if you wrote off a high creatinine to taking creatine and missed a timely diagnosis. To reassure your doctor and/or yourself, you can ask for a “serum/urine creatinine ratio,” which corrects for your creatine supplement. This is a hassle (requires you collect 24-hr urine sample), so I wouldn’t do it unless your blood test result is bugging you.

I wouldn’t worry: if you are training and have a reasonably healthy set of habits (e.g. no smoking, meth, or binge drinking), you should be well above average health, and this should be obvious to your doctor, even with a few lab values a bit out of range.