I thought I'd start the new year with a helpful hint. We often get people on the boat who are divers that get only 35-40 minutes a dive and always have. When that happens, we try to give them some hints on how to dive to get longer dives. A few months back we had a customer on the boat that commented "you're the first dive company we've been with that actually helped us stay down longer" or something to that effect. Apparently when the question of breathing came up, most dive crews they have had just said something along the lines of "dive more and it'll get better" and not given actual hints at how to change it right away.
So here we go... there's no guaranteeing this will improve your bottom time, but we've found that most divers can have a great deal of improvement over just a couple days time by working on these. I've had divers go from a history of 35 minute dives, to staying down 50-60 minutes or more just within a couple days of trying these "tricks".
- Slow down. Slow down your breathing (more on that later) and slow down your diving. People who zip around tend to burn up their air faster, tend to see less stuff, and actually tend to cover less ground because they're using up their air at a much faster rate than they would if they went at a relaxed pace.
- Don't swim with your arms. One, every time you swing your arms forward, it practically acts like a bellows to your lungs, making you take a breath. Two, for as much pull as you get using your arms to swim, you are creating almost as much resistance, so the net gain is negligible. Arm swimming is pretty much a new diver's problem, but I know I was guilty of it for quite a while in my early diving days. I finally got to where I wanted to stop it and I actually clasped my hands behind my back while diving to stop it. I'd already improved my bottom time at the time quite a bit, but when I started doing that, I just about immediately added 5-10 minutes to my bottom time. Every now and then a diver's likely to have to use their arms to make a turn, back up and such, and that's OK (although those that dive a lot can often find a way to kick that stops that need), but constant arm swimming really burns the air.
- Slow down your breathing!!! That one's the big one. As a boat captain, I watch a lot of bubbles. I can pretty much tell who's coming up first as soon as my divers are three feet underwater. There are divers who's bubbles are literally hitting the surface every second or two, then there are divers who's bubbles are hitting the surface every 7-8 seconds or longer. Guess which one's are going to be down for a long time.
From the get-go, you are told "deep and slow" when it comes to breathing on scuba. It really does work. Implementing it is another thing altogether. Diving is very exciting, and very foreign, at first. Breathing underwater isn't all that natural, and the tendency is to breath quite rapidly for a lot of people. Even once they get over the initial discomfort there's a tendency to breath somewhat shallow and rapidly for lots of divers.
There's a couple of tricks for breathing slow. Some instructors will say, pretend there a long straw down to the bottom of the tank and you want to slowly sip it as you inhale. That works for some people. I've heard others say that you should inhale for 7 seconds, then exhale for 7 seconds. That works for a lot of divers, but it's kind of tough for many to go from 1-2 seconds each direction immediately to 7 seconds each direction. An instructor once told me to count the duration of my inhale, then count the duration of my exhale (set a counting rhythm and then do it a few times while breathing in and out), then try to extend it by a second each direction for a few counts. He told me to not spend the entire dive counting, but just to check my breathing rhythm and then try to extend it by a second or so maybe every ten to fifteen minutes during the dive. Over the course of a couple dives I found myself lasting a lot longer.... this method worked the best for me.
Nowadays I pretty much ignore my breathing rate, but every now and then I'll have a customer who's a very good breather (it's embarrassing to be out breathed, but it does happen on occasion) and I'll have to slow down my breathing. I find that if I set a slow rate at the start of the dive as soon as I hit the bottom, I'll maintain that slow rate throughout the dive and last longer than if I wasn't paying attention to it at all.
Over the years I've seen divers go from "hoovers" to being able to last 75/85/90 minutes or more just on improvements in technique. Once they are there, they need to look for dive companies that actully allow those kinds of bottom times (we do unless deco status or other circumstances affecting dive length exist, hint hint) on their charters, but at least they can maximize their tanks even if the dive companies they are with have earlier cut off times.
Diving is one of those "sports" where even relatively out of shape divers can breath with the athletic ones once they find their rhythm. Good luck and happy diving!