I'm not sure why a chiropractic practice should have such specific advice about hyponatraemia for athletes (and 'iron man' participants in particular), but this page makes an interesting read.
These days GPs are just as likely to be asked questions by enthusiastic runners, from semi-professionals to energetic grannies who want to run a marathon.
This article advises that taking so-called sports drinks is not enough to replace the salt that someone exerting themselves for long periods is likely to lose.
It points out that you may lose as much as 3.4g of salt in sweat in an hour, and you would need to drink about six litres of the average sports drink each hour to replace it.
This is clearly impossible, and here you will find suggestions about what should be done before and during the activity.
Why go there: could come in handy.
Downside: but not very often.
Information from: Wellington Chiropractic, Ontario, Canada.
This is fairly complicated advice, but don't worry. It's only a paragraph.
Its value lies in the fact that we have all checked a patient's electrolytes as part of routine screening, only to find a puzzling low sodium.
The first thing I do is to repeat it and hope that it will be normal, but what if it isn't? This short piece gives you some clues.
Why go there: may help avoid a referral.
Downside: hard work.
Information from: British Endocrine Society.
This NHS-backed guideline on the management of hyponatraemia in adults consists of five pages, but all the information is on just two of them.
In this short space, it gives a concise overview of symptoms and diagnosis before discussing the treatment of both asymptomatic and symptomatic patients.
You won't find yourself doing much of this in a Monday morning surgery, but you will be wiser regarding the options available.
Why go there: it's brief.
Downside: hospital orientated.
Information from: Clinical Resource Efficiency Support Team.
Dr Barnard is a former GP in Fareham, Hampshire
Website of the week
This address takes you straight to a well-formatted four-page document. This is aimed at hospital practitioners, but drug-induced hyponatraemia is also associated with many drugs used by GPs. As the article points out, with increasing polypharmacy and an ageing population, the prevalence of drug-induced hyponatraemia is likely to increase. Also interesting to note is that most patients with drug-induced hyponatraemia are asymptomatic and often only detected incidentally.
Why go there: this is relevant information.
Downside: fairly complex.
Information from: Australian Prescriber.
Address: www.australianprescriber.com/upload/pdf/articles/675.pdf .