FIGURE 3.

Correlation between fitness (V̇O₂max) and resting CBF measures, separately for younger (green) and older (red) groups. (a)MRI GM cerebral perfusion and GM transit time, and (b)TCD MCAv and CVCi. Lines of best fit are shown for younger and older groups separately with Spearman's r and significance values. *Represents significant effect (p ≤ .05). Abbreviations: CVCi, cerebrovascular conductance; GM, gray matter; MRI, magnetic resonance imaging; MCAv, middle cerebral artery blood velocity; TCD, transcranial Doppler; V̇O₂max, maximum rate of oxygen consumption