PT  - JOURNAL ARTICLE
AU  - Steven Whatmough
AU  - Stephen Mears
AU  - Courtney Kipps
TI  - Serum sodium changes in marathon participants who use NSAIDs
AID  - 10.1136/bmjsem-2018-000364
DP  - 2018 Dec 01
TA  - BMJ Open Sport & Exercise Medicine
PG  - e000364
VI  - 4
IP  - 1
4099  - http://bmjopensem.bmj.com/content/4/1/e000364.short
4100  - http://bmjopensem.bmj.com/content/4/1/e000364.full
SO  - BMJ OPEN SP EX MED2018 Dec 01; 4
AB  - Introduction The primary mechanism through which the development of exercise-associated hyponatraemia (EAH) occurs is excessive fluid intake. However, many internal and external factors have a role in the maintenance of total body water and non-steroidal anti-inflammatory medications (NSAIDs) have been implicated as a risk factor for the development of EAH. This study aimed to compare serum sodium concentrations ([Na]) in participants taking an NSAID before or during a marathon (NSAID group) and those not taking an NSAID (control group).Methods Participants in a large city marathon were recruited during race registration to participate in this study. Blood samples and body mass measurements took place on the morning of the marathon and immediately post marathon. Blood was analysed for [Na]. Data collected via questionnaires included athlete demographics, NSAID use and estimated fluid intake.Results We obtained a full data set for 28 participants. Of these 28 participants, 16 took an NSAID on the day of the marathon. The average serum [Na] decreased by 2.1 mmol/L in the NSAID group, while it increased by 2.3 mmol/L in the control group NSAID group (p=0.0039). Estimated fluid intake was inversely correlated with both post-marathon serum [Na] and ∆ serum [Na] (r=−0.532, p=0.004 and r=−0.405 p=0.032, respectively).Conclusion Serum [Na] levels in participants who used an NSAID decreased over the course of the marathon while it increased in those who did not use an NSAID. Excessive fluid intake during a marathon was associated with a lower post-marathon serum [Na].