When you start freediving equalization usually sets the depth limit.
After some training it is oxygen consumption. Then again equalization and after learning frenzel it will be lack of oxygen again. This has been the main obstacles for depth hungry freedivers to overcome - but there is a third problem.
Suggestions on how to avoid squeeze:
- First and foremost have a slow progress to depth every season.
- Do not pack air.
- Rapid changes in lung volumes could be a factor, but latest indications is that packing does not increase the likelyhood of squeeze.
- If possible: turn before contractions - indications say that heavy contractions might be the main cuplrit.
- Slow ascent (some suggests the first 10-15 meters are the most important).
- Do not stretch out at depth.
A general relaxed approach all through the dive.
- Warm up with (at first) gentle FRC or negative dives
- Drink less before diving deep.
- Breath out well before the surfaceIf you want to go deep you have to facilitate bloodshift as much as possible.
Also note that your RV can differ from day to day
Treatment of squeeze:
- Stop diving.
- Lean forward and spit out as much salivablood as possible.
- Drink lots of water the following hours.
In severe cases breath at least 5 minutes of oxygen (on land).
- Eat vitamins, get extra hours of sleep.
- Drink more.
In severe cases you might need many days of rest, even weeks.
When the risk/effects of near drowning is dealt with, there are still small internal wounds that has to heal (and scar).