Did Exercise Affect My Blood Test?

Hard exercise can change several blood results for hours to days, and some markers for longer.6 If you have already had a blood test, this tool shows which of your results may have been influenced by your last hard effort. It is based on typical timelines from published studies and on my own clinical experience.

1. What was your last hard effort?
2. When did it end?
3. When was your blood or urine sample taken?
4. Which results were measured?

How to read the results

  • Likely affected: the sample was taken while this marker is typically still changed after this kind of effort.
  • May have been affected: the sample was taken in the window where some people have recovered and others have not.
  • Exercise effect unlikely: the sample was taken after the typical recovery window. If the result is abnormal, exercise is a less likely explanation.

Why timing matters

A result taken soon after a hard effort can look abnormal even when nothing is wrong, but its meaning depends on symptoms and other results.6 The opposite can also happen: CRP can rise with a delay after exercise, so a sample taken in the first hours can look misleadingly normal.10,12 Each marker follows its own timeline, which is why the tool shows them separately.6

References

Every figure and statement in this tool is linked to a source: the original study where my article cites one, otherwise my own article on the topic. The small numbers in the text refer to this list.

  1. Dr. Antti Rintanen: Troponin After Marathon and Endurance Events: When to Worry
  2. Baker et al. 2019. Exercise-induced cardiac troponin elevation: An update on the evidence, mechanism and implications. Int J Cardiol Heart Vasc.
  3. Lippi et al. 2010. Acute variation of leucocytes counts following a half-marathon run. Int J Lab Hematol.
  4. Wu et al. 2004. Effects of 24 h ultra-marathon on biochemical and hematological parameters. World J Gastroenterol.
  5. Risøy et al. 2003. Delayed leukocytosis after hard strength and endurance exercise: Aspects of regulatory mechanisms. BMC Physiology.
  6. Dr. Antti Rintanen: Post-Marathon Blood Work: Understanding Your Blood Test After a Marathon and When Results Return to Normal
  7. Hodgson et al. 2017. Acute kidney injury associated with endurance events-is it a cause for concern? A systematic review. BMJ Open Sport Exerc Med.
  8. Dr. Antti Rintanen: eGFR in Athletes: Why Your Result May Be Misleading
  9. Dr. Antti Rintanen: Proteinuria After Exercise: What Athletes Need to Know About Protein in Urine
  10. Cerqueira et al. 2019. Inflammatory Effects of High and Moderate Intensity Exercise-A Systematic Review. Front Physiol.
  11. Bernat-Adell et al. 2021. Recovery of Inflammation, Cardiac, and Muscle Damage Biomarkers After Running a Marathon. J Strength Cond Res.
  12. Dr. Antti Rintanen: Inflammation Markers in Athletes: CRP and Recovery
  13. Dr. Antti Rintanen: Liver Enzymes in Athletes: When Elevated ALT and AST Are Not a Liver Problem
  14. Kim et al. 2008. Serum activity of alanine aminotransferase (ALT) as an indicator of health and disease. Hepatology.
  15. Siegel et al. 1980. Creatine kinase elevations in marathon runners: relationship to training and competition. Yale J Biol Med.
  16. Mougios 2007. Reference intervals for serum creatine kinase in athletes. British Journal of Sports Medicine.
  17. Baird et al. 2012. Creatine-kinase- and exercise-related muscle damage implications for muscle performance and recovery. J Nutr Metab.
  18. Sierra et al. 2019. Association Between Hematological Parameters and Iron Metabolism Response After Marathon Race and ACTN3 Genotype. Frontiers in Physiology.
  19. Lampe et al. 1986. Elevated serum ferritin concentrations in master runners after a marathon race. Int J Vitam Nutr Res.
  20. Dr. Antti Rintanen: High White Blood Cell Count After Exercise: When to Worry 
  21. Dr. Antti Rintanen: Mean Platelet Volume High
  22. Dr. Antti Rintanen: Creatine Kinase Elevated in Athletes: Truths About High CK After a Workout

Sources

The timelines summarise the studies cited in these articles:

This tool is for general education. It does not interpret your own results or replace an assessment by your doctor. Individual recovery varies with fitness, hydration, heat, medication and the type of effort.