[trux]

Well, it does not make a lot of sense doing it in this way, but of course you can try - the risk is not really increased - in fact you will still do a hypercapnic (CO2) table, just with a variable breath-hold time, so the increased CO2 level will still protect you against BO.

I am telling it makes little sense, because the variable apnea time and decreasing recovery time, means that you either start with too easy breath-holds (hence having no training effect), or end with too difficult ones (and you'll be forced to abandon). Well, is still may be possible to find some balance, but I believe plain CO2 table is more efficient. With a simple CO2 and O2 tables you can also watch your progress very easily, which may be more difficult with a table with two variables.

It may be also more difficult to handle the timing, if you are doing it wet and do not have a pre-programmed table on a PC, PDA, or a watch.

I rather recommend combining two tables after each other. There are many such training sessions with multiple tables available in the Apnea Training Manager (I believe you are registerd too). However, the full sessions, unlike plain exercises (tables) are available to regular accounts only (not the free ones).

Our club training sessions (1 hour) often consist of warm-up (exhale apneas, emtpy lung apneas), a hypercapnic table, and a hypoxic table.