THis appear in The Times newspaper last week....
Fatigue acid may help curb tiredness
By Mark Henderson, Science Correspondent
THE theory of why muscles tire during exercise may have been overturned by research that could transform the training regimes of athletes.
Scientists have discovered that lactic acid, the compound blamed for muscle fatigue, actually prevents tiredness.
At present, athletes minimise the accumulation of lactic acid in their muscles after exercise using techniques such as ice baths and warm-down sessions. But the theory has been challenged by evidence that people whose muscles do not accumulate lactic acid get tired just as quickly as those whose muscles do.
The research team, led by George Stephenson and Graham Lamb of La Trobe University in Melbourne, and Thomas Pedersen and Ole Nielsen of the University of Aarhus in Denmark, stripped the surface membrane of rat muscle fibres so they could alter the chemical conditions inside.
As lactic acid levels were increased, the scientists found that the muscle fibres fatigued less quickly. This appears to happen because rising acidity interferes with the effect of chloride ions, which normally damp down the muscle’s excitability. The findings, published today in the journal Science, suggest that lactic acid helps the muscles remain responsive to nerve signals for longer, and therefore tire less.