Breathing O2 during surface interval

[happy-diver]

But my main concern was why someone would want to breath O2 in their car on the drive home (supposedly at altitude) and during surface intervals. Expensive habit if you're not bent.

Mate how can you concentrate with this money thing spinning around your head like a cyclonic vortex

I breathe leftover from blending o2 when I am sitting in my comfy chair watching Scubaboard and TV

Now that's some surface interval

 

[OS74]

The question on oxygen at surface interval for increased safety is interesting.

There is a Swedish study performed but not (to my knowing no publicized yet). The researcher was the guy presenting at the Norwegian seminar described to earlier in this thread.

Purely verbal discussion I understand that they have seen significant reduction in vein bubble formation (ultrasonic) with an 02 interval immediately after the dive vs air surface interval.

He also referred to MN90 decompression tables that have variants with O2 intervals during surface interval. I have no experience of these tables, but perhaps someone here has?

 

[jale]

The question on oxygen at surface interval for increased safety is interesting.

There is a Swedish study performed but not (to my knowing no publicized yet). The researcher was the guy presenting at the Norwegian seminar described to earlier in this thread.

Purely verbal discussion I understand that they have seen significant reduction in vein bubble formation (ultrasonic) with an 02 interval immediately after the dive vs air surface interval.

He also referred to MN90 decompression tables that have variants with O2 intervals during surface interval. I have no experience of these tables, but perhaps someone here has?

That was the tables I was referring in my previous post.
MM90, MT92 tables and others have tables for breathing oxy at surface.(and 9 and 12M also)

 

[boulderjohn]

I was reading a quote: hike high, sleep low. But my main concern was why someone would want to breath O2 in their car on the drive home (supposedly at altitude) and during surface intervals. Expensive habit if you're not bent.

You do this because you are making a calculated risk in making an ascent to altitude in violation of norms. Within norms for such an ascent, you would not bother.

As for the expense, it depends upon how much you have to pay for your oxygen. The cost varies dramatically from supplier to supplier and even within a supplier for different people. The first time I bought my own oxygen, the dealer wanted to charge me $90 for a 300 cubic foot bottle. I told him I knew someone who paid $60 there, and he said, "OK, I can do that." Later on I switched to another company and paid $30. Then I switched back to the first company and pay $20. Breathing surface O2 for an hour might cost me a dollar or so.

 

[Scuba Client]

Ascending to altitude, on the other hand, is essentially the same as ascending during a dive. You are moving from greater pressure to lesser pressure, so you have to plan for decompression. That is why NASA and the Pentagon use decompression specialists in their planning--going from sea level to high altitude flight or into space creates a dramatically fast loss of pressure that can lead to DCS.

I understood the part 'planning for decompression', but if you have already decompressed after the dive and are driving home which is at a higher altitude, wouldn't you already be acclimatized? Or is breathing O2 just a precautionary measure? Someone did mention in another post that it was an overnight stop at a lower altitude.

'You do this because you are making a calculated risk in making an ascent to altitude in violation of norms. Within norms for such an ascent, you would not bother.'

OK, makes sense.

 

[boulderjohn]

I understood the part 'planning for decompression', but if you have already decompressed after the dive and are driving home which is at a higher altitude, wouldn't you already be acclimatized? Or is breathing O2 just a precautionary measure? Someone did mention in another post that it was an overnight stop at a lower altitude.

'You do this because you are making a calculated risk in making an ascent to altitude in violation of norms. Within norms for such an ascent, you would not bother.'

OK, makes sense.

The second part of your post seems to contradict the first part, showing an understanding, so I am not sure my response is appropriate.

It is not a matter of being acclimatized, but most importantly, you have not decompressed after the dive. You are still decompressing for some time after a dive. That is why you need a surface interval. That is why you are supposed to wait a certain amount of time before ascending to altitude. DAN's recommendations for flying are based on ascending beyond 2,000 feet; if you are only ascending 1,500 feet, you should be OK. I ascend 3,200 feet, and I do this before the recommended time for DAN, the US NAvy, and NOAA. That is why

 

[Scuba Client]

The second part of your post seems to contradict the first part, showing an understanding, so I am not sure my response is appropriate.

It is not a matter of being acclimatized, but most importantly, you have not decompressed after the dive. You are still decompressing for some time after a dive. That is why you need a surface interval. That is why you are supposed to wait a certain amount of time before ascending to altitude. DAN's recommendations for flying are based on ascending beyond 2,000 feet; if you are only ascending 1,500 feet, you should be OK. I ascend 3,200 feet, and I do this before the recommended time for DAN, the US NAvy, and NOAA. That is why

I was just about to reply the same thing. It's the flying after diving principle. I did some research and recalled on memory when a friend of mine hiked to base camp in Nepal around 17k feet I believe. And I was thinking he never mentioned using O2, although they were tired after hiking 7-days. Then it hit me, they hadn't done a decompression dive to a certain depth which may require you to remain at that level. Confusion on my part, no doubt.

 

[boulderjohn]

Acclimatization to altitude is a factor on all altitude dives, but in most recreational dives it really doesn't matter much. Your ascent to altitude is supposed to be considered the equivalent of a first dive, but for probably at least 90% of divers at typical diving altitudes, they have been there long enough to be able to start clean. Where I dive, I actually arrive from a higher altitude, so I am better than clean. When you are diving at very high altitude, though, acclimatization must be taken very seriously. The US Navy has only a single paragraph about diving above 10,000 feet. It is written in bold-faced, red type, and it essentially says don't do it without special permission.

 

[Scuba Client]

The second part of your post seems to contradict the first part, showing an understanding, so I am not sure my response is appropriate.

It is not a matter of being acclimatized, but most importantly, you have not decompressed after the dive. You are still decompressing for some time after a dive. That is why you need a surface interval. That is why you are supposed to wait a certain amount of time before ascending to altitude. DAN's recommendations for flying are based on ascending beyond 2,000 feet; if you are only ascending 1,500 feet, you should be OK. I ascend 3,200 feet, and I do this before the recommended time for DAN, the US NAvy, and NOAA. That is why

I've been reading your blogs. Very interesting.

'In 1938, psychologist Henry Murray first described this personality trait, saying achievement motivation is marked by “prolonged and repeated efforts to accomplish something difficult.'

'One problem that high N Ach divers may encounter is dealing with the lack of recognition for what they have achieved'.


I never found technical diving difficult. Searching information from books and online forums, and learning from various mentors is what motivates me. I understand where you're coming from when it involves technical divers, especially on this and other forums, the pecking order is intense. I've observed that some divers prefer to just accumulate c-cards as a sign of status, instead of traveling the world to gain experience and interact with technical divers from various nations. I also believe good technical divers can dive with anyone since they are confident in their abilities.

 

[Scuba Client]

Acclimatization to altitude is a factor on all altitude dives, but in most recreational dives it really doesn't matter much. Your ascent to altitude is supposed to be considered the equivalent of a first dive, but for probably at least 90% of divers at typical diving altitudes, they have been there long enough to be able to start clean. Wear I dive, I actually arrive from a higher altitude, so I am better than clean. When you are diving at very high altitude, though, acclimatization must be taken very seriously. The US Navy has only a single paragraph about diving above 10,000 feet. It is written in bold-faced, red type, and it essentially says don't do it without special permission.

What depths are you diving to and what are the bottom times? How long do you wait before driving home after a staged decompression dive? Do you rely on altitude calculators?