Original Article: Received 20 February 2020 Accepted 4 May 2020
Association between collapse and serum creatinine and electrolyte concentrations in marathon runners: a 9-year retrospective study
Daniel Fitzpatrick | Edward Walter | Todd Leckie | Alan Richardson | Mike Stacey | Alex Hunter | Steve Short | Neil Hill | David Woods | Rachael Grimaldi | Rob Galloway | Luke Hodgson
Objective: Abnormal biochemical measurements have previously been described in runners following marathons. The incidence of plasma sodium levels outside the normal range has been reported as 31%, and the incidence of raised creatinine at 30%. This study describes the changes seen in electrolytes and creatinine in collapsed (2010รขโฌโ 2019 events) and noncollapsed (during the 2019 event) runners during a UK marathon.
What difference could the outcomes of the research make to treatment / prevention?
This paper examines the prevalence of changes in renal function and sodium levels after a marathon. Again, this is in healthy and collapsed individuals. It found rates of low sodium were similar between both groups, and at a much lower level than previously reported before changes in drinking advice.
It also showed a similar change in creatinine which is a blood test used to measure kidney function. There was a risk compatible in acute kidney injury in most runners, either collapsed or healthy. However we donรขโฌโขt know if this is a รขโฌโขtrueรขโฌโข kidney injury as again it reversed very quickly and there are reasons that running itself would cause a rise, without an actual kidney injury.
How would a medical practitioner use this information?
To understand that low sodium is less common that previously thought in marathon runners, and doesnรขโฌโขt always cause collapse. Also that renal injury appears to be prevalent in marathon runners.
Would the public gain anything from knowing this information and if so, what would that be?
They can know that using the รขโฌหdrink to thirstรขโฌโข strategy, instead of drinking to a schedule is effective in reducing risk of having a dangerously low sodium level.
Note: further research is being done, so it may be that these are potential outcomes rather than actual ones.
The Brighton Marathon Research Group’s ongoing research includes a study of biomarkers or kidney cell injury in runners. This is a much more direct measurement than creatinine, which is a proxy measure. Tests (TIMP2 and ILGFP1) have shown a marked increase in healthy runners. This suggests that there is an actual renal injury occurring in runners. This may be important for long term heath in these taking part in a large number of marathons.
Additional research the Brighton Marathon Research Group are doing monitors temperature in runners using thermometer pills that the runners swallowed. The data collected so far shows many runners with core temperatures raised to above 40 degrees C, who were well and healthy. This provides more information to help out understanding of exertion heat illness. Watch this space for the completed research.
Commentary written by:
Dan FitzPatrick (He/Him)
Sport and Exercise Medicine Registrar (ST3), Charing Cross Hospital
Honorary Research Fellow, SASME, University of Brighton
First Team Doctor, Rosslyn Park FC
Independent Match Day Doctor, Premiership Rugby
Council Member, Royal Society of Medicine Sport and Exercise Medicine Section