New device to test athletes' sweat for improved performance

Ireland Track athletes, who are preparing for the 2012 Olympics, have been testing a device designed to improve performance by optimising their hydration levels during training.

Dehydration can undermine both mental and physical performance, including causing tiredness and cramping.

Analysis of sweat samples taken after training is unreliable because the key compounds oxidise when in contact with air.

"It does not give a real measure of what is happening during exercise," New Scientist quoted Fernando Benito Lopez at the Clarity Centre for Sensor Web Technologies at Dublin City University, as saying.

And thus, the researchers have developed a device that assesses hydration levels while athletes are training. It is based on an absorbent pad strapped to the athlete's body, which draws sweat through a narrow channel containing pH sensors.

Benito Lopez is investigating the use of two different types of sensor-One uses a patch of pH-sensitive textile and the other uses an ionic dye which changes colour in the presence of sodium ions.

An LED is used to illuminate the sensor while a second light-sensitive LED detects the colour changes by measuring the intensity of light reflected off it.

The resulting readings, sent wirelessly to the trackside, tell the coach the sodium content of the athlete's sweat and therefore their hydration level.

Based on this information, the coach can fine-tine the athlete's training programme. Initial tests show the pad can continuously monitor pH changes for up to 3 hours.

This could be potentially very useful, said Charlie Pedlar, a research physiologist at the Endurance Performance and Coaching Centre at St Mary's University College in Twickenham, UK, who worked with the British Olympic team in Beijing, China, in 2008.

"We measure body weight before and after training to measure water loss through sweat and breathing," he said.

But he said that this does not give enough information to optimise athletes' water intake and avoid dehydration.

The researchers are investigating whether it is possible to apply the same approach to lactate, which is also present in sweat.
The device will soon be tested on a rugby team in England.

Details of the research will be presented at next month's Lab-on-a-Chip European Congress in Dublin.