Sports drinks aren’t enough to boost performance - salt may help: Research

The scientists, led by Juan Del Coso of the University of Camilo Jose Cera, suggest that salt supplementation increases the amount of fluid drunk, compensates for electrolyte loss and promotes its retention through osmosis, thus improving performance.

According to Cera the concentration of sodium, potassium and chloride in sports drinks are well below the levels lost in sweat, therefore reducing their efficacy.

The study​

Researches carried out a randomised double-blind trial involving 26 experienced triathletes who were matched for age, body type and training status.

During a real half-ironman triathlon, the salt group ate a total of 2580 mg of sodium, 3979 mg of chloride, 756 mg of potassium and 132 mg of magnesium while the control group was given cellulose.

Blood samples were taken before and after the triathlon to measure electrolyte levels in serum and subjects completed a questionnaire rating tiredness.

The salt group completed the triathlon at a “significantly”​ lower time (307 minutes compared with 333 for the placebo), outperforming the placebo for speed across all three categories ( 8.26 metres/second compared with 7.74 in cycling, for instance).

However there was no difference in perceived exertion or muscle soreness between the groups.

“These benefits were probably driven by a higher voluntary fluid intake during the race and higher serum electrolyte concentrations. Moreover, oral salt intake did not produce side effects when compared with a placebo. Thus, oral salt supplements might be an ergogenic aid for long-distance triathlon events,” ​the study says.

Sodium – a single message that ignores scientific advice​

Sodium alone was approved by the European Food Safety Authority (EFSA) in 2011 for its role in muscle function​​ but the claim failed to make the permitted list because EU member state authorities deemed it to contradict public health advice to reduce sodium intake.

According to European Specialist Sports Nutrition Alliance (ESSNA) officer, Dr Mark Tallon: “This is an example of the EU regulating on an issue for policy reasons rather than science reasons. There are two different issues, one to do with repeated daily consumption of salt from food sources and then one-off consumption for sport."​

He called for the EU to revise its sodium stance.

“With adequate labelling on a product specifying the conditions for use – only to be taken during intense activity where there is a risk of dehydration – EFSA could provide good health policy for the general population that is not at the expense of those engaging in a special activity.”​

Source: Scandinavian Journal of Medicine and Science in Sports​

Published January 2015, doi: 10.1111/sms.12427

"Effects of oral salt supplementation on physical performance ​during a half-ironman: A randomized controlled trial"​

Authors: J. Del Coso, C. González-Millán et al.