I'm trying to reach 7 minutes(dry) and no matter what I do 6 min 30 is my max .I use an oximeter and the lowest O2 values after ending the hold are consistently 35-40% so obviously very close to a blackout.Is there anything I can do to add 30 secs?I am relaxed - eyes closed , lying on bed counting down contractions (over 3 minutes worth)nearly the whole time.I have tried packing but it doesn't seem to work for me,so I'm stumped.