The government tells us to eat less salt. But hard-training athletes give up plenty of the stuff through their sweat and are advised to replenish with electrolyte drinks. As part of his regular series on triathlon nutrition, Joel Enoch explains how to find the right balance.

In the the last article I wrote for T-Zero focused on the importance of electrolytes (such as sodium) in the fluids we consume during training to reduce the risk of hyponatraemia, among other things. However, sodium is simply one part of common table salt, otherwise known as sodium chloride. The advice on electrolyte intake thus seems to conflict with recommendations by the Food Standards Agency (FSA) regarding a low salt diet? Is there an increased risk to athletes’ health with the ingestion of fluids containing high levels of sodium chloride?

In the UK, the FSA recommend a maximum intake of 6g of salt per day for adults without any history of high blood pressure; this is about a teaspoonful a day (the current national average is 8.6g). The FSA also highlights a need to be aware that this figure refers to all salt contained within foods and not just the extra that might be added during food preparation. Up to 75% of the salt in our diet is already added to foods so it can be easy to consume too much, even without the extra sprinkle we apply at the dinner table.

I often comment to those I am working with and advising that ‘sport nutrition’ (and ‘nutrition’ in the wider sense) is essentially the process whereby we replace lost nutrients or the nutrients the body needs to function. In the case of sports performance we know that sodium is lost in sweat and consequently there is a requirement for it to be replaced. Research has shown that typical sodium losses in sweat during 1hr of exercise are around 920mg, but figures as high as 3000mg have been recorded – equating to around 7.5g of salt – thereby emphasising the need to replenish stores.

From a health perspective, general recommendations such as those stated above are therefore not necessarily appropriate to athletes losing large quantities of sodium in sweat through training and racing. Hence the use of electrolyte drinks containing even high levels of sodium (300-455mg) should not be a concern. Research also shows that the body is highly effective at regulating its sodium content and can get rid of or ‘cling onto’ sodium in times of surplus or deficit. However, timing the consumption of drinks containing sodium is still important and so athletes should still look to hydrate 3-4 hours before exercise with around 500mls of fluid, consume fluid during training and also rehydrate after exercise. It is also useful to remember that sodium can be replaced with salty snacks such as pretzels.

To summarise, healthy adult triathletes should look to replace sodium lost in sweat during exercise. However, there is little risk that the level of sodium present in sports drinks (typically 140-455mg which equates to 0.35-1.1g of salt) is likely to increase the risk of conditions linked to a high salt diet. Indeed, for the athlete, the negative effects on heath and performance are more likely to be seen if sodium is not replaced.

About Joel

Joel has competed in both European and World Championship Age-Group level triathlons. In 2009 he also raced Elite on two occasions and if it wasn’t for a dodgy zip on his tri suit he wouldn’t have done too badly! This year is his 3^rd ‘once in a lifetime opportunity’ to prove something on an international age-group level and he hopes to win some medals this time around! He has a BSc in Sports Science from Brunel University, an MSc in Nutrition from Bristol University and has been a Sport Scientist for the Lucozade Sport Science Team since the beginning of 2009. He works with both Olympic athletes and people who have never heard of carbohydrate!

Lucozde has recently launched a new low-calorie electrolyte drink, Lucozade Sport Lite

Previous postings

How, when and why to use sports drinks

Hyponatraemia – what it is and how to avoid it

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