This evening I did a low intensity run (10km - 46'), a very easy workout based on my standard.

Tomorrow morning (about 12-13h after the run) I should do the blood test..

There is the possibilities to get an altered result due to this workout few hour before the withdrawal or not? If yes, should I wait until the day after tomorrow?

I will do these exams:

  • Complete Hematocrit
  • Hemoglobin
  • Cholesterol LDL & HDL
  • Triglycerides
  • Cortisol
  • Folate
  • Vitamin B12
  • Ferritin
  • Serum iron
  • Transferrin
  • sodium
  • potassium
  • copper blood test
  • magnesium
  • thyroid

I wrote that list because maybe there is the possiblity that the workout has an effect only on some tests.

I'm not english nor american, so I am not really sure about the translation accuracy

Thank you...

1 Answer 1


If it's low-intensity, the workout won't have any relevant effects on the blood test. Even if it was a high-intensity workout, the test results might be influenced by it, but probably not to the extent that you'd get a false positive of any abnormal indication.

There are countless other factors which influence these tests, such as time of day, amount of sleep, nutrition, temperature, altitude, immune status, and even psychological stress, which is why blood levels are given as a range, not a fixed point. There's no point trying to balance out all these influences – it's impossible.

That's also the reason why blood tests are only be relevant if their result is pathological, that is, far outside the normal range. Where exactly the result is within the normal bounds is important to analyze for research purposes, but generally not something your doctor will be interested in. Your doctor can only tell you whether there's something seriously wrong with your blood – he can't distinguish between a "barely healthy" person and a "perfectly healthy" person, as both will be within the normal bounds. HDL/LDL cholesterol might be one exception to this, since few people are in the optimal range, but nevertheless it holds true by and large.

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