Interesting. Never been in salt water. I always get jealous of people who can float like nothing. I also have asthma so that's probably why I can't properly float? I can doggie paddle for some time until my body just gets tired, lol.
Yeah the asthma doesnt help, the idea is to inhale as much as possible and hold your breath to allow you to float easier, then when you need to breathe you exhale and use your arms and legs a bit to again inhale to avoid sinking. You dont want to hold your breath to the point of absolutely needing air, as that would just tire you out.
Its so easy to float in the ocean I dont really have any fear of going quite aways out if things are relatively calm. More afraid of sharks than the water itself lol. Swam way out to this platform in the bay of biscay where everyone else was taking boats. I was mainly worried about sharks.