[Ubuntu]

I read the sticky thread on the basics of free diving, so will now ask (several) questions not answered in that thread. If my questions are already answered before, just a link to such archived thread will suffice.
Driving to and from work I spend 35 minutes in the car. I hold my breath in moderation while driving. Is the possibility of a blackout enough to have me rather stop this practice? Typical scenario would be breathing for half minute then apnea for one and half minute.
Thanx for this magic forum.