"I'm not sure that acceleration would be any less strenuous in a liquid environment than otherwise. "

You can't distingish the difference between accelerating at 9.8 m/s/s and the effects of Earth's gravity.
Take a whale out of water and it dies from the acceration of 1 gee of Earth gravity. Put the whale in an ocean on a planet which has ten times that of Earth and it wouldn't notice much difference- except it's not going to able to leap out of the water*.

* One also higher water pressure with depth, so on a 10 gee world a 300' dive would be the same as a 3000' dive. Instead of every 33' equaling an atm, every 3.3' equals an atm. Of course what matters to a astronaut who is sitting opposed to reclined is the inability of the heart pumping blood to the brain (creating a blackout). Being in a liquid environment would act as a gee suit, but there would limits. But if reclined and in a liquid environment one, I would think one could withstand hundreds of gees over long periods of time.