Fatigue is largely in the mind, not the muscles, research by South African scientists has discovered.
The brain steps in and makes the body feel weary to stop it being overworked, thanks to a signalling molecule that seems to tell the brain when it is time to slow the pace of the body.
Research showed that blood levels of the molecule, interleukin-6 (IL-6), were 60 to 100 times higher than normal after prolonged exercise, according to Paula Robson-Ansley, from the University of Cape Town.
Countering IL-6 might have a similar effect to performance enhancing drugs, enabling cyclists and marathon runners to last that extra mile.
Robson-Ansley injected seven club-standard runners with either IL- 6 or a dummy drug and recorded their times over 10 kilometres.
A week later, the experiment was reversed.
On average the athletes ran nearly a minute faster after receiving the non-active placebo, New Scientist magazine reported.
Most of the group had finishing times around 41 minutes, so this would have been the difference between winning and losing.
Robson-Ansley’s own athletic career was cut short partly due to a condition called underperformance syndrome (UPS). She was training for the British rowing squad for the 1996 Olympic Games when her body failed her.
”Suddenly a five-kilometre run felt like I’d run a marathon the next day,” she said.
She hopes the new research will lead to treatments for UPS and chronic fatigue syndrome. One approach might be to block IL-6 receptors in the brain — proteins that react to the signalling molecule — using antibodies.
Anti-doping experts are already worrying the technique could be abused by unscrupulous athletes wanting to train harder. – Sapa-DPA