Skip-breathing is briefly holding your breath between inhales / exhales. Theoretically, it could cause hypercapnia, or excess carbon dioxide in your blood. Serious complications from skip-breathing seem unlikely, nevertheless it is a bad habit that should be avoided. Why would someone do it?

• Unconscious activity

  Sometimes we do things without even thinking about it. Any habit formed during basic certification could easily persist without any conscious effort. Force yourself to become conscious and it won’t take long to break the habit.

• Trying to save air

  The less you actively breath the less air you use, right? Wrong. Holding your breath, even momentarily, raises the amount of carbon dioxide in your body, which requires more oxygen to flush. The net effect is that any savings in air usage are cancelled, or become negligible.

• Trying to control buoyancy

  I’m guilty of this one, especially during fin pivot exercises. Fine tuning your buoyancy through breath control is natural, and expected. However, breath control does not equal breath holding. Rather than holding your breath, practice achieving the same effect through shallower breathing.

Slow, controlled breathing is best, while any form of breath holding, even skip-breathing, is not recommended. Try to keep your breathing non-stop throughout, and watch how quickly good habits are formed.

I’ve got an exciting announcement for The Diving Blog!

This Friday I’ll be starting our first regular series of articles. This one will be about fish identification.

Fish identification is one of my favorite parts of diving. It’s exciting to talk about what fish you saw back on the boat, or to look them up in a book. Over time you begin to learn quite a few fish. It can be daunting at first, however. If you check out one of these familiar books, you’ll notice they’re thick (over 500 pages!). Where do you begin?

Each article in this series will profile a different marine animal. We’ll see where it lives in the world, what is it’s behavior, and how can you recognize it. By breaking the monumental task of learning fish down into smaller, digestible articles I hope to help you become adept at fish identification, one creature at a time. I’m excited about it because it will also be a learning process for me.

I haven’t decided if this series will be weekly or bi-monthly. Let me know if you have any suggestions, either about this series or the blog in general. Feel free to leave a comment or even send me an email. I want this blog to be as useful for you as it is for me.

Basic certification in most organizations permits diving to depths of 20m / 60ft. Secondary, advanced certification extends this depth to 40m / 130ft–the recreational diving limit. Past this and you enter the realm of technical diving. Where did this limit come from? There are two factors that led to this number:

• No-stop limits

  40 meters is about as deep as one can dive on air while still having somewhat of a bottom time (albeit less than 10 minutes, with a safety stop strongly recommended) before decompression stops are required. Even brief moments at depths beyond this without stops during ascent will almost certainly yield some form of decompression sickness.

• Nitrogen narcosis

  Technically nitrogen narcosis can take effect anywhere below 60 feet, but below 130 feet it reaches the point of being unmanageable without specialized training. The effects can still be strong even at 130ft, hence PADI generally recommends planning deep dives around 100 feet.

These are the two basic reasons behind the now-standard recreational dive limit.

Dive trips are exciting, but can be a real chore when it comes time to pack for the flight. There’s the advantage of having all your own equipment and not using questionable rentals versus the task of getting it all to your destination.

Dividing equipment between carry-on and checked luggage can ease the burden slightly. Then the problem becomes, “What equipment should I check?” Here are four considerations to help with this decision:

• Legality

  If you’re not allowed to have it on a plane, then the decision has been made for you; so don’t even bother with that dive knife. I’ve heard mixed results from carrying pony bottles, with most saying they are fine. Check with the TSA’s (if flying from the US) set of ever-changing rules for up-to-date information.

• Cost

  How expensive is the particular item? Don’t expect the airlines to reimburse you for broken goods, just ask this guy. If it’s expensive, you may want to consider carrying it with you.

• Breakability

  Likewise, if something is likely to be broken when tossed (even inside a case), it also may be better off with you. There is a variety of luggage specifically designed for protecting dive gear, so you may want to give that a try. Keep in mind, however, that security may go through your bag and not put all the pieces back in exactly the manner that guarantees their safety.

• Importance

  How easily can you go without something? More so than just breaking something, luggage can get lost. If a checked item doesn’t show up until the end of the week, will it significantly affect your diving? For this reason, most people will forgo their own weights on trips.

• Space

  If it won’t fit in an overhead space, then the choice has been made for you; either check it or leave it at home.

If you still have no idea what to do, then here’s a starting point:

Carry-on: regulator, mask (especially if prescription), camera equipment.

Check: BCD, fins, snorkel, wetsuit, knife.

Use the above criteria to tweak these lists until you are satisfied.