Diving and altitude

[60plus]

I know that the risk of DCS increased if you go higher above sea level after a dive and that you should not fly until 24 hours has passed after a dive (This is also a requirement of my insurance).
There may be instances on holiday where I do 2 dives in a day each of about 45 minutes at 10 to 18 meters. What are the guidelines on going on trips to altitude the following day in the 6,000 to 8,000 ft range?

 

[tursiops]

I know that the risk of DCS increased if you go higher above sea level after a dive and that you should not fly until 24 hours has passed after a dive (This is also a requirement of my insurance).
There may be instances on holiday where I do 2 dives in a day each of about 45 minutes at 10 to 18 meters. What are the guidelines on going on trips to altitude the following day in the 6,000 to 8,000 ft range?

Airplanes are pressurized to 8000 ft, so going to 8000 ft is like flying. I'd wait 24h.

 

[JVos]

Some people think altitude doesn't matter...logical people know better.

 

[60plus]

Thanks for quick reply. I knew aeroplanes drop their pressure to that at 8000 ft but this is done quickly as they rapidly climb to about 38,000 ft. The sort of climbs to altitude I would experience on holiday would be a much slower bus trip with sightseeing stops. Typically the ascent would take 2 to 3 hours. So I wondered if the bus trip is more like taking decompression stops whereas the plane is more like an uncontrolled ascent. I maybe should have posted more fully initially. The trips I am thinking of are the astronomical observatories on Tenerife or Madeira, or the volcano tours on Lanzarote.

 

[Bob DBF]

Is there anyway you can make the trip, then make your dive?

Perhaps @boulderjohn can chime in as I know he has experience with this.


Bob

 

[60plus]

I don't have too much control over the scheduling of the trips and I have to fit my diving in with other family members holiday activities. I got caught out by this on a previous holiday. I took a day off diving so I could go to just under 6,000 ft the following day. I intended to complete my OW the following day, however when that day arrived the weather rapidly worsened and OW training was canceled immediately and all diving cancelled after the first dive of the day as the sea was too rough.

 

[boulderjohn]

Thanks for quick reply. I knew aeroplanes drop their pressure to that at 8000 ft but this is done quickly as they rapidly climb to about 38,000 ft. The sort of climbs to altitude I would experience on holiday would be a much slower bus trip with sightseeing stops. Typically the ascent would take 2 to 3 hours. So I wondered if the bus trip is more like taking decompression stops whereas the plane is more like an uncontrolled ascent. I maybe should have posted more fully initially. The trips I am thinking of are the astronomical observatories on Tenerife or Madeira, or the volcano tours on Lanzarote.

This is a tricky question. If you go to the Rocky Mountain Region dive forum, you will see a sticky I posted on this sort of thing. We who dive in New Mexico have to ascend to altitude by driving every time.

Trying to come up with something more definitive, I contacted several very famous names and asked them to co-author an article about it. They politely refused. There is no published research on it, and they did not want to have their names associated on something for which there was no acceptable research.

So I wrote something on my own. It is waiting to be published in a new section in ScubaBoard on diving knowledge. It is ready to go, but the section needs the OK. When that happens it will appear. If it does not appear soon, I will publish it myself and provide a link. In the meantime, check out the link I posted above. Some of the information is outdated, but it should be helpful.

 

[flyboy08]

You didn't contact me?


Just kidding! I look forward to reading your white paper.

 

[Rocketman3]

I doubt you will find much that gives you an ok - if you decide to do your diving and then your altitude trip - do everything you can to minimize your nitrogen load. Dive with Nitrox, stay a bit shallow, end a bit early, don’t push NDL, etc. Also have a plan to get off the mountain if you start to not feel well.

I had the same issue a few years ago - did the manta ray dive in Kona Hawaii, but we were staying in Hilo, so we had to drive to altitude shortly after. Our solutions were to take the long road (lower altitude), get a slow start, etc.

Good Luck

 

[boulderjohn]

I have written a new, more current, and more detailed explanation of the issues involved with an ascent to altitude. You can find it on my resources page.