Salt vital for intense competitions

I've long been intrigued by the effects of salt on the body, and whether the reality is in line with official recommendations.

The NHS Choices website states that adults should eat no more than 6g of salt a day (about a teaspoon) or it could dangerously raise the blood pressure.

But now, researchers from Spain highlight the importance of adequate salt intake, particularly for athletes. Dr Juan del Coso Garrigos of the Camilo Jose Cela University, Spain, investigated the impact of salt on performance in a triathlon.

The race, a "Half Ironman", involved 1.9 km of swimming, 90 km of cycling and 21.1 km of athletics. In addition to their usual rehydration drinks, a group of the athletes also took 12 salt capsules - in three doses - during the competition. The plan was to replacing 71% of the estimated sodium lost via sweat.

This group finished the race 26 minutes faster on average than a group given rehydration drinks and placebo tablets. The drinks alone replaced about 20% of the lost sodium.

"This positive effect on performance relates to an increase in the concentration of electrolytes in the blood, improving the water and electrolyte balances during the competition," said Dr Coso Garrigos.

"If we choose a mineral water as a rehydration drink in sport, which contains a low level of sodium, we would be replacing only the liquid while the concentration of sodium in our blood would gradually become diluted," he warns.

While sports drinks companies know that adding more sodium would be more beneficial during exercise, "a greater concentration of sodium would also make the drink have a more salty taste and would reduce the possibilities of succeeding in a market where flavour is key to obtaining good sales figures," he added.

This is important to know in the (perhaps unlikely) event of my taking part in a gruelling race lasting over two hours.

J. Del Coso, C. et al. Effects of oral salt supplementation on physical performance during a half-ironman: A randomized controlled trial. Scandinavian Journal of Medicine & Science in Sports 14 February 2015 doi: 10.1111/sms.12427

Kate Richards