Creatinine level after exercise?

I just went for a check-up and had a treadmill exercise test and a blood test. I’d fasted for 13 hours.

I was very surprised they had me do the treadmill test before the blood test, and asked about that twice, but they insisted. Results were good (87% of max age-adjusted heart rate with no ischemia (*)), and hearing that reassurance made me feel healthier than I’d been feeling! :wink: I want to discuss this peculiar form of hypochondria I have, but first ask a question:

The one thing on the blood test that disturbed the doctor was my 1.5 level of creatinine – 1.4 is the maximum recommended level. I Googled briefly and what I read made me wonder if a rise in blood creatinine would be normal after exercise?

(If my hunch is right, and testing blood after exercise was bad idea, you may tell me to find a better doctor/hospital. But I’m afraid I drove over an hour there, to the best hospital in my region! )

(* - EKG was abnormal before the test, but that’s normal since my heart’s infarcted once or twice; it didn’t get more abnormal during the test. :smiley: )

It is not unusual for serum creatinine to rise post exercise although it should stay within a normal range. The more vigorous the exercise the more likely you are to see a rise, particularly if you are not well hydrated.

The difference between 1.4 and 1.5 mg/dl is trivial, but it may be that what raised a medical eyebrow is being at the upper range of normal.

The above is my opinion, obviously, but would this post not belong in GQ?

FWIW, Wikipedia writes

My exercise was fairly vigorous – I was breathing hard and feeling tired – and I was not well hydrated – I’d had no water at all for 13 hours. (They insist “nothing by mouth” is permitted before blood test, perhaps assuming that saying “water is OK” will lead patients to think soft drinks or beer is OK. :wink: :smack: )

:confused: Yes, the difference is trivial, though so is the difference between 1.3 and 1.4. Or between 1.5 and 1.6. As shown above, “typical” is 0.7 to 1.2. Young doctor may have been slightly … well, Pedant-ic (;)) to draw the line just where the computer did, but it’s logical to “draw a line” somewhere.

The doctor was concerned enough to tell me to repeat the creatinine test every month. :dubious: :eek:

My understanding is that IMHO is only forum where seeking medical advice is allowed.

I’m a little confused by your thought process. You asked twice if doing the stress test prior to the blood test would mess up the results, and you were told it would not. The doctors, who spent years studying medicine and anatomy and were hired at the best hospital in the region, told you this. But if strangers on the Internet tell you otherwise, you’d believe them over the doctors? Why? (Just to clarify, I’m not saying the doctor’s always right, and I have personally been in situations where I would have been better off not listening to the experts. So please don’t take this post as being snarky or accusatory. But I am still curious.)

I asked the tech and the nurse. Doctor was busy, though he was present for the actual stress test. I accepted the answer I was given, but had second thoughts when Googling (and Chief Pedant’s response) suggested that the exercise would have increased my creatinine level.

I have much respect for expertise at SDMB; there is at least one M.D. who answers questions here.

I do trust the doctor at this, the best hospital in the region, but not 100%. I would definitely not trust many of the doctors in the government hospitals and even private clinics here in rural Thailand. If you think I’m prejudiced to feel this way, then you are under-informed.

I agree with being skeptical of “the internet” as a source for information, but as a physician I can tell you it’s OK to be equally skeptical of your physician as a source of information. None of us know everything and most of us need to shorthand nuances lest every patient become too time consuming. I’ve spent a few decades in medicine, have current American Board certifications in Internal Medicine and Emergency Medicine, and nice scores on my competency exam. But of course I could be just faking it and I’m really a 13 year old who likes to post.

Anyway, the thing I suggest is a combination of sources, and these days you can even do a literature search as a lay person to corroborate or expose statements. In addition, many of these common questions are addressed for the lay person. Here, for example.

The real difficulty is handling the nuances, and that’s where a live physician who knows you is vastly superior to me or the literature.

Take the issue at hand: an individual who has a creatinine level at the upper limit of normal–perhaps even into the abnormal range. Because creatinine is normally cleared close to 100%, and because an even marginally elevated creatinine can (not necessarily does) mean there is significant renal impairment, the physician who sees a value of 1.5 mg% is concerned. Because ordinary exercise does not typically raise serum creatinine levels, the physician shorthands to the patient that this does not happen and that it’s fine to have an exercise test first. On a message board, though, the nuances of this discussion don’t take place. A simple question is raised: “Is a rise in creatinine normal after exercise?” The correct answer is that it does rise, transiently, and not by much unless the exercise is vigorous or something else–such as dehydration–retards clearance. And the further fine point is that it should not rise into an abnormal range. This is a technical answer and not the practical one the patient’s doctor is being asked: “Does it make any difference if I exercise before my blood test?” The answer to that question is “No,” because any abnormal (or high normal) creatinine should be followed carefully, and antecedent exercise would not be considered a sufficient reason to ignore such a result.

This is a good reason why it’s difficult to give good medical advice over the internet…

Thank you, Chief Pedant. I will follow Doctor’s instruction and repeat the creatinine measurement (but without antecedent exercise) in a few weeks.

I should start a different thread to discuss my peculiar hypochondria. I’d been feeling weak and tired for weeks before the doctor’s visit but now, despite that no remedy was prescribed, I feel much healthier! The same effect – vanishing of real-seeming symptoms after a simple doctor’s check – has happened to me several times before.

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FWIW, Wikipedia writes
I understand. I am a large athletic guy and avidly like to lift weights. I have been doing so for many years. I have changed doctors 3 times in the past 20 years. I get asked the same question from every one of them. “Do you take Steroids?” I say no and they look at me skeptically. They can see I have a big barrel chest, huge arms shoulders and chest and automatically assume that my high creatinine levels are caused by steroids and not natural production. It is frustrating so I have learned to not work out for a few days before any lab test and guess what…when I don’t work out my levels are normal. Now my question for the doctor is why do I create so much and is there anything wrong with my kidneys that I need a few days to filter out the high levels. They shrug their shoulders.