“Sorry I turned the dive when I did,” said every diver at least once in their life. “Yeah, what the hell were you thinking you fuckwitted piece of shit? How DARE you turn the dive when you reached the volume of gas that we carefully agreed would be the minimum that would safely get us both back to the surface in case of an emergency?!? Asshole!” said no diver ever. So why do we keep apologising? Of course it’s always disappointing to call the dive. When we’ve spent all this time and money and energy on training and gear and travel. When we’re finally enjoying a dive that we’ve been daydreaming about and looking forward to for months when we’ve been sitting at our desks or stuck behind someone counting out nickels to the supermarket cashier. When we’re actually in the place where we spend all our time wishing we were… and now you’ve got to be the one to say, “Time to leave.” It’s disappointing. But necessary. For a variety of reasons, we’re only allowed to stay for so long. It’s almost certainly the rarity of the experience that makes it as precious as it is. And so, in pursuit of the preciousness we wind up obsessing over just how long we can stay. At least old habits like skip-breathing are out of fashion (as they are dangerous, physiologically destructive, and counter-productive), but we still wind up obsessed with our breath. “How much gas do you have left,” everyone on the boat wonders to one another. We joke about how it’s such a waste to have all that pressure left in the tank. We all direct jocular jealousy at that one person who always comes back with way more than everyone else. Everyone behaves as if there are gold, silver, and bronze medals waiting for everyone based on their RMV. But it’s all irrelevant nonsense. We breath how we breathe. And thinking about it is just going to fuck it all up. Wanna see a practical example of that? Watch this: The person sitting nearest you can totally hear you breathing. Your breathing just changed, didn’t it? Calm down, they probably can’t hear you breathing. What’s more, they don’t care. But you care, so you focused on your breathing. And fucked it all up. A trick I learned at some point or another that I always teach during first aid classes (especially diver first aid classes, considering the danger of pulmonary injury): the best way to learn someone’s respiratory rate is tell them you’re taking their pulse, take their pulse for 30 seconds then, without moving or seeming to be doing anything other than continuing to take their pulse, count their respiratory rate for 30 seconds. Because if you tell them, "I’m going to count your breaths," they’re going to breath weird. When you’re focusing on your breath when you’re diving: you’re breathing weird. And almost certainly driving up your RMV. Breath naturally. CCR divers call it Minimum Loop Volume* Pulmonologists call it Tidal Volume. Whatever you call it... just breath that way. Yeah, of course there are tricks to lowering your gas usage:
Be properly weighted.
Be properly trimmed.
Be properly buoyant.
Be in shape.
Wear appropriate thermal protection.
Be comfortable and trained for what you're doing and the gear you’re using.
There are a bunch of things you can do to lower your RMV. That’s all for another time. But chief among them: stop thinking of it as a competition. Go diving. See cool stuff. Float around and enjoy being in that cave or on that reef or looking at that wreck that you’ve been counting down the days towards for the last 6 months. Stop staring at your pressure gauge. Stop worrying that you’re going to be the one to ruin it for everyone when you thumb the dive. No one cares how much gas you have when you get back to the surface. Yeah, there will be a bunch of unused, safety-buffer gas left in your tanks — as long as you get back to the surface. Ideally, having shared an awesome dive with some buddies. -----
* Minimum loop volume has fallen out of favor to Optimal loop volume, but that's a different conversation.