(Top) Patterns of PCr recovery after exercise in a normal control subject (open circles) and in patient no. 12(closed circles), who reached the same level of cytosolic acidification during recovery. The rates of revovery are expressed as TC of the monoexponential equation best fitting the experimental points.(Bottom) Rate of PCr postexercise recovery (TC PCr) as a function of minimum intracellular pH reached during recovery in 15 patients with juvenile migraine. The dashed area represents the 95% confidence interval defined by the root mean square error of regression line linking the rate of PCr recovery to the minimum pH from 15 young normal control subjects.