Showing posts from February, 2015

pH Threshold as a Predictor of Endurance Running Performance

Lactate and pH Lactate threshold as a percentage of VO2max has long been associated with distance running and cycling performance. But lactate is not a cause of fatigue. Rather, the accumulation of lactate is an indication of what's occurring. Lactate can accumulate without a change in muscle pH. In fact, lactate production prevents or delays changes in pH. So, could pH threshold be a more sensitive indicator of performance capacity than lactate? Below is data and a graph from a pH threshold test conducted on a treadmill in a lab. From the graph, you can see the lactate threshold falls at roughly 9.5 mph or 6:19/mile. Here, we saw an increase from 3.02 mmol/L to 4.78 mmol/L (+1.76 mmol/L). But note that blood pH did not change from 9.5 to 10 mph (7.38 to 7.37). But, pH did fall between 10 and 10.5 mph. This demonstrates that even though lactate starts accumulating, pH does not necessarily change. In theory, an athlete should be able to maintain a pace in that w