Fig 6. Cerebral haemodynamics (‘Haem’) of O₂Hb and HHb for two seals during two key phases of a dive.

(A) Mid-surface interval and (B) early in a dive when secondary reoxygenation occurred. Dots represent median concentration change. Error bars represent the interquartile range. Changes are shown as relative changes from CBV minima during a PDSI. Dives by Vebjörn, n = 23. Dives by Ulf, n = 54. Data can be found here: https://doi.org/10.5061/dryad.k67cg66. CBV, cerebral blood volume; HHb, deoxyhaemoglobin; O₂Hb, oxyhaemoglobin; PDSI, postdive surface interval.