When I freedive, I'm often weighted so that I'm neutral buoyant at -10m. So the last 10 meters I will start to float upwards, and thus go faster. But that's no

When I freedive, I'm often weighted so that I'm neutral buoyant at -10m. So the last 10 meters I will start to float upwards, and thus go faster. But that's not the issue here. It's the pressure difference when ascending. > [1] Ascent-induced hypoxia is caused by a drop in ppO2 as ambient pressure is reduced on ascent. The ppO2 at depth, under pressure, may be sufficient to maintain consciousness but only at that depth and not at the reduced pressures in the shallower waters above or at the surface [1]: https://en.wikipedia.org/wiki/Freediving_blackout https://en.wikipedia.org/wiki/Freediving_blackout