Hi David,
Definitely interesting facts you posted here, but before I start arguing, please let me send this warning out: although I think it may be OK to experiment with hyperventilation at experienced freediver who's performance is very high, who did hundreds of breath-holds of 5 or 6 minutes and more, and who perfectly knows his/her limits, and masters the reactions of his body to all the different states during the apnea, is able to recognize the closing hypoxia limit, and especially who only trains in secure environment, I still think that recreational freedivers, spearos, or competitive freedivers of all but the top levels should definitely keep their distance from hyperventilation as much as possible.
Already like that it is quite difficult to keep newbies from hyperventilating - they all tend to do it naturally, so when they then read about freedivers doing 7 minutes breath-holds with hyperventilation (even if it is a very mild one), they are able to copy it, just to get from their 2:30 to 3:00. Once they start doing it at dry static apnea, they will tend to keep it even when diving and risk their health and life.
And also: the impact of a light hyperventilation is quite different at static apnea and at real diving, where the diving reflex is much more important (to swith the muscles into their anaerobic metabolism mode early, saving so oxygen for the brain). It is not without a reason that there are several FRC divers with performances close to the current CNF world record (or even over it), applying hypoventilation (less than normal ventilation) before their dives to invoke early DR. The current record of Constant Weight No-Fins is 80m held by Martin Stepanek (that was very likely a classical full lung dive), but FRC divers like Sebastien Murat (the pioneer of FRC diving) or William Trubridge dive to that depth (or below it in case of Bill) after limiting their breath-up considerably and building high CO2 level.
I wouldn't though recommend inexperienced divers to experiment alone neither with hyperventilation nor with hypoventilation - the sudden change of the body reactions may be confusing for someone without sufficient experience who is not able to read the signals properly. It needs its time and training.
Otherwise, your examples were interesting, but in fact they both compare similar breath-up's with hyperventilation, although it is quite mild in the first case. It would be much more interesting trying to work on kicking in the DR as fast and as deep as possible, and comparing the results then. If you are interested, have a look at the article of Sebastian Naslund (Cebaztian) at Fridykning.se about the FRC clinique of Sebastien Murat, and the surprising results. I quote just one part, but the whole article is worth of reading - it is the comment of the author of the article about his very first (and only partial) attempt after attending the FRC clinique:
As for the comment of cdavis about purge breathing - well, when you snorkel or spear, of freedive recreationally, you usually use a snorkel, that already by itself increases the CO2 level, so a light purge before the dive may not be too risky. As long as you know your limits and do it consistently, you are likely staying in your safety margin. Working on the FRC style instead may be still worth of it, though anyway.
Definitely interesting facts you posted here, but before I start arguing, please let me send this warning out: although I think it may be OK to experiment with hyperventilation at experienced freediver who's performance is very high, who did hundreds of breath-holds of 5 or 6 minutes and more, and who perfectly knows his/her limits, and masters the reactions of his body to all the different states during the apnea, is able to recognize the closing hypoxia limit, and especially who only trains in secure environment, I still think that recreational freedivers, spearos, or competitive freedivers of all but the top levels should definitely keep their distance from hyperventilation as much as possible.
Already like that it is quite difficult to keep newbies from hyperventilating - they all tend to do it naturally, so when they then read about freedivers doing 7 minutes breath-holds with hyperventilation (even if it is a very mild one), they are able to copy it, just to get from their 2:30 to 3:00. Once they start doing it at dry static apnea, they will tend to keep it even when diving and risk their health and life.
And also: the impact of a light hyperventilation is quite different at static apnea and at real diving, where the diving reflex is much more important (to swith the muscles into their anaerobic metabolism mode early, saving so oxygen for the brain). It is not without a reason that there are several FRC divers with performances close to the current CNF world record (or even over it), applying hypoventilation (less than normal ventilation) before their dives to invoke early DR. The current record of Constant Weight No-Fins is 80m held by Martin Stepanek (that was very likely a classical full lung dive), but FRC divers like Sebastien Murat (the pioneer of FRC diving) or William Trubridge dive to that depth (or below it in case of Bill) after limiting their breath-up considerably and building high CO2 level.
I wouldn't though recommend inexperienced divers to experiment alone neither with hyperventilation nor with hypoventilation - the sudden change of the body reactions may be confusing for someone without sufficient experience who is not able to read the signals properly. It needs its time and training.
Otherwise, your examples were interesting, but in fact they both compare similar breath-up's with hyperventilation, although it is quite mild in the first case. It would be much more interesting trying to work on kicking in the DR as fast and as deep as possible, and comparing the results then. If you are interested, have a look at the article of Sebastian Naslund (Cebaztian) at Fridykning.se about the FRC clinique of Sebastien Murat, and the surprising results. I quote just one part, but the whole article is worth of reading - it is the comment of the author of the article about his very first (and only partial) attempt after attending the FRC clinique:
As for the comment of cdavis about purge breathing - well, when you snorkel or spear, of freedive recreationally, you usually use a snorkel, that already by itself increases the CO2 level, so a light purge before the dive may not be too risky. As long as you know your limits and do it consistently, you are likely staying in your safety margin. Working on the FRC style instead may be still worth of it, though anyway.
Last edited:
)