Surface Intervals

Skarz
If you can't turn it up with a search, here's my notes, courtesy of Kirk Krack

Example with Dr. Batles tables;
If you attempted a freedive to 21 meters for 1:30 (spearfishing) you should wait on the surface 2:20 before your next dive.

If your next dive was to 36m for 1:30 (intermediate level competitor) your
surface interval (SI) should be 3:27.

A dive to 69m for 2:20 which is typical of an expert competitive freediver
the surface interval before any other freedive is 9:13.

He developed a simple rule of thumb; If the depth of your freedive was <25 meters then your SI should be twice your total dive time.

If your depth was > 25 meters then your SI should be a minimum 8 minutes.

His article/paper is called "The Attitude a Breath Hold Diver Should Take to
Avoid Arterial Gas Embolism". He's Associate prefessor of University of Balearic Islands (Spain) and Chairman of Medisub, Hyperbaric Research Institute.

">25 meter and your SI should be minimum 8 minutes"

this does not say anything about about number of dives on that day or the day before??

it's only after suffering suspected DCS yesterday that I'm taking a proper interest in this thread.

hi Sam
symptoms were extreme fatigue, pounding headache and upset stomach till late that night. was o.k by the next day though. dive was a few negitives till 15m, longish dive to 28 then 23m, then one dive to 90m about 9 min after last warmup dive, thats it. Was advised by eric f to limit warmups to 20m and keep them short but i overshot slightly by accident. was also advised to take a day off between deep dives but did 85 the day before. i'll listen to the man next time.

others here are sucking o2 after their dives but i have always declined as was told there is a chance of it messing with 02 receptors?

b

Bevan,

Sorry to hear about the DCS incident. It wouldgreatly help the freediving community if you could post a clear message to the apneadiver e-mail list (as well as here), with your precise profiles (even time of day of the dives), depth/time of each dive, etc... as well as a description of the onset of symptoms etc... Water temperature, suit config, would also be helpful. Dehydration?

It would help dispel many myths. I think you are the first person to suffer a real DCS hit with a warm up dive of less than 30m (although the 85m dive the day before probably played a role too).


Eric Fattah
BC, Canada

One thing we should all keep in mind as we speculate about DCS tables for freediving is that even the Scuba tables are never a guarantee against getting bent. It seems to me that there are people who have followed the tables and still have gotten bent because of other circumstances or because, for their own physiology, the tables do not apply 100%.

I'm sure I've read stories in DAN's Alert Diver about scuba divers who have gotten bent even when they followed standard procedure.

I think that after Benjamin Franz's incident and now Bevan's, we can risk asserting that diving deep on consecutive days increases the likelihood of DCS/DCI.

Take care, Bevan!

Pete Scott
Vancouver, BC

Can the extreme fatigue I feel after a training session (4 or 5 dives to 40-50m) be DCS?

If so, is it actually a problem to get slightly bent?

Al

Could be Sam. but the fatague was unlike anything i've felt from diving before. it felt like a severe case of flu that came on within an hour. upset stomaches can easy be explaind away in egypt but one other unusual symptom i forgot to mention was a stinging sensation when urinating. this is a dci symptom i beleive? mild or not, i didnt feel to healthy that day. i think i'll play it safer from now on.

b.

I looked up the following article on the DAN website. http://www.diversalertnetwork.org/medical/articles/article.asp?articleid=65

Here are some interesting excerpts:

"The most common manifestations of DCS are joint pain and numbness or tingling. Next most common are muscular weakness and inability to empty a full bladder. Severe DCS is easy to identify because the signs and symptoms are obvious. However, most DCS manifests subtly with a minor joint ache or a paresthesia (an abnormal sensation like burning, tingling or ticking) in an extremity.

"In many cases these symptoms are ascribed to another cause such as overexertion, heavy lifting or even a tight wetsuit. This delays seeking help and is why it is often noted that the first symptom of DCS is denial. Sometimes these symptoms remain mild and go away by themselves, but many times they increase in severity until it is obvious to you that something is wrong and that you need help."

"For recreational divers, where diving is not a livelihood, a more conservative approach is called for to further minimize the chance that a diving injury will recur.

- After pain-only DCI where there are no neurological symptoms, a minimum of two weeks without diving is recommended."

"Decompression illness affects scuba divers, aviators, astronauts and compressed-air workers. It occurs in approximately 1,000 U.S. scuba divers each year. Moreover, DCI hits randomly. The main risk factor for DCI is a reduction in ambient pressure, but there are other risk factors that will increase the chance of DCI occurring. --> [my emphasis] These known risk factors are deep / long dives, cold water, hard exercise at depth, and rapid ascents."

This statement gives me pause: "Since DCI is a random event, almost any dive profile can result in DCI, no matter how safe it seems." So let's not get too addicted to DCI "tables."

DAN recommends a two week waiting period after a minor hit. Maybe you should call DAN for advice in your case. www.diversalertnetwork.org

I'd say that your symptoms are in line with DCI symptoms.

Cheers,

Pete