Runners with mild anaemia could avoid lengthy investigations and unnecessary treatments by suggesting the diagnosis of 'runner's anaemia' to their concerned doctors. That's the implication of a fascinating case history report published in the prestigious Journal of the American Medical Association (JAMA).

A female lawyer had teams of doctors baffled by her persistent anaemia, which did not respond to iron supplementation. An exhaustive battery of tests failed to shed any light on her symptoms until a review of her history revealed that her usual exercise consisted of an 8k run every other day.

It was then hypothesised, explains her doctor, that her presentation was consistent with the rarely-diagnosed condition known as 'runner's anaemia' - a mechanically-induced destruction of the red blood cells resulting from the pounding of feet on pavement, associated with plasma volume expansion, leading to further dilution of the red cells.
To confirm the diagnosis the patient was advised to stop running for four weeks, after which a significant rise in her red cell volume was apparent. 'Since this change was of no physiological or symptomatic consequence, she resumed running with the comfort of a definitive diagnosis for her persistent pseudoanaemia,' he reports.

Runner's anaemia, also known as 'footstrike haemolysis' was first noted more than a hundred years ago and documented through studies of long-distance runners in 1943. It was not until much later though that an explanation for the condition was provided. What is now known is that the apparent anaemia is caused by a combination of red blood cell breakdown and associated blood loss, complicated by expansion of the plasma volume - the fluid part of the blood.

'Mild anaemia that is tolerated by an avid, devoted runner should raise the possibility of a diagnosis of runner's anaemia,' concludes the author, 'Érecognition of this syndrome is important in patient management, which should include reassurance and avoidance of unnecessary therapies.'

JAMA 2001 Aug 8 286(6), pp714-716

Isabel Walker