"Undeserved Hits"
The Thin Black Line
"Just follow the dive tables or your computer and you'll be fine." This common piece of advice is not only factually incorrect, but also creates additional liability by failing to properly warn divers of the risks they accept by partaking in this sport.
Will your personal dive computer help you avoid getting bent? Surely, this marvel of modern technology can make a huge difference as it continuously reassesses the estimated inert gas load in your 22 different tissue compartments, but these are still just approximations based on countless assumptions.
The algorithms loaded into your PDC are mathematical wonders, but they aren't able to provide guarantees. The no-deco limits (NDLs) provided by these devices effectively draw a thin black line in a large grey area. Decades of data have gone into drawing these lines, but there is no way to account for the vast majority of factors affecting DCS susceptibility.
Sleep quantity/quality, stress level, age, pre-existing health conditions (known or unknown), scar tissue, hydration, and many more factors can have a large impact on the likelihood of getting bent, whether you stayed within no-deco limits or not.
There Are No "Undeserved" Hits
With an infinitessimal number of exceptions, there are no freak unexplained accidents with decompression sickness. Most every case can be attributed to factors that were either missed or ignored. Here's an example:
Divemaster Jack has been diving for five years now and loves taking clients on wreck dives. He knows where to look for the biggest goliath groupers, and he still smiles every time while gliding through a swim-through.
It's been a long week, and he's been diving four times most days on wrecks and shallow reefs. There's no issue with his surface intervals, but he's getting tired. Unfortunately, he also has some family drama going on that's had him staying up later than he probably should. Of course, the stress of all this has killed his appetite, and he's drinking a large coffee each morning to get going.
Jack does a double dip on one of his favorite deep wrecks in the morning, breathing nitrox and staying within his limits. Back on the boat, he complains of pain in several joints as well as a nagging headache. After a few minutes, he sits down, realizing he might have a minor case of the "bends" and starts breathing off a pure O2 bottle. One ride in the hyperbaric chamber later, doctors confirm that he's been hit with an "undeserved" case of decompression sickness.
My question: In what way was that undeserved?
Taking Care of Yourself
Avoiding decompression sickness is not just about following the tables or listening to your dive computer. Age, illness, scar tissue, heart malformations, hydration, stress levels and sleep are just a few additional factors that you, as the diver, need to manage.
If you find yourself about to don scuba gear and realize that diving might not be the best idea, say something. Your buddies will understand and support you entirely. If they don't, then they are unsafe dive buddies and you're better off finding new ones.
Self assessment is absolutely crucial, as most of the factors affecting DCS susceptibility cannot be measured with tools found in a dive kit.
If you're going to dive, do it right. Don't put yourself (and therefore your team) at risk by neglecting to take care of yourself.
As with all content on this site, this article was typed out key-by-key by Cuda, who now needs a nap.