Don’t immerge yourself if you’re not in perfect psychophysical conditions and if your last meal was less than 4 hours ago or if you had a snack in the last 2 hours.

Go to the periodical specific medical check-ups at least once a year and frequent a skin diving immersion course at a qualified school.

Don’t hyperventilate but immerge yourself after one or two deep breaths.

Immerge yourself always tied to a line fixed to a Sub signal buoy (red flag with a diagonal white band visible at 300 m) and in slightly positive hydrostatical balance.

Immerge yourself always with a buddy in order to carry out the apneas alternating yourselves so that the diver on the surface can control at sight the companion in immersion.