Lactic acid gets some pretty bad press, but it doesn’t exist in the body for more than a few seconds. It is quickly converted into lactate and hydrogen ions and it is these little guys that drop the pH in the muscles making them acidic and painful. This article from World Rowing explains more..
Lactic acid has been cast in the role of nemesis, as the necessary evil to higher athletic performance; not just in rowing, but in many sports over the years. The scientific knowledge, however, has advanced in recent decades and lactic acid seems to play a more complex role than is often assumed.
“First of all,” explains Dr Trent Stellingwerff, lead of Innovation and Research at the Canadian Sport Institute Pacific, “we should call what we are measuring lactate and not lactic acid. Within the muscle, 99 per cent of the lactic acid (LaH) separates immediately into lactate (La-) and hydrogen ions (H+). It is the H+ that is the problem.”
“Lactate is both fuel and metabolic waste product,” says Alex Hutchinson, author of the Sweat Science articles for runnersworld.com. “The body has different ways of mobilising its fuel stores and it all depends on when you need the fuel.”
“When you are performing over your V02 max (maximal aerobic capacity),” says Stellingwerff, “you have to draw on anaerobic metabolism to provide the required energy. A 2000m rowing race is done at 98 to 110 per cent of power at V02 max. This is why rowers produce so much lactate.”
“Professional marathoners, by comparison, run at 85-90% of V02 max and would probably never have a lactate measurement over 4 mmol (millimoles),” he says, “but in rowers it can be around 15-18 mmol and sometimes even a bit higher.”
Measuring lactate, however, is an indirect measure, since it is not the lactate itself that causes the acidosis (or drop in pH inside the muscles). The hydrogen ions (H+) produced with the lactate cause the drop in the muscle’s pH. Normal pH in the body is 7.2, but can drop as low as 6.6 if it were to be measured in rowers after a race, according to Stellingwerff.