Huge air consumption even after +200 dives

[Eric_K]

I'm your height, but only weigh 185 lbs with 16% body fat. I've had to work on my consumption my entire dive career. If indeed you are in shape (I lift weights and know that there are varying levels of effort by people), I'd suggest you work on your inhalation amount. You may be sucking down much more than your body needs, perhaps overcompensating for too much weight. In any case good luck!

 

[Diver-Drex]

Possibly stay a little shallower. Let the group go to the bottom and check stuff out. Staying higher in the water column will give you a better vantage point, you’ll be seen by the group easier and it will cut your air usage.

If you’re doing 15 meter dives, staying at 10m could help.

 

[KenE]

It appears you have worked out most of the common causes of high gas consumption. I am in much the same situation. The best advice I can give you is to try to remove stress as much as possible. My consumption went up when I was leading our group and back down when someone else led. So, I started working on the stress level when leading and brought my rate back to normal. Stress adds to breathing rate, thinking about breathing rate increases breathing rate. So, stop thinking about it and start enjoying leading groups. Find positives to focus on and not negatives, this will help reduce stress and consequently your breathing rate. I now practice breathing rates out of the water and stopped worrying about it underwater. My breathing rate dropped due to muscle memory and less stress. Have fun and keep diving!

 

[Tycksel]

Get a 15 liter tank. Problem solved. And you'll probably relax knowing that you have plenty of gas, and by relaxing you'll consume less, and eventually you may be comfortable switching back to a smaller tank.

I did few dives with 15L tank last winter, but it gave me maybe 5min more divetime. I only use 800g weight with 12L tank and with 15L tank I'm maybe 4-5kg overweighted.

I'm your height, but only weigh 185 lbs with 16% body fat. I've had to work on my consumption my entire dive career. If indeed you are in shape (I lift weights and know that there are varying levels of effort by people), I'd suggest you work on your inhalation amount. You may be sucking down much more than your body needs, perhaps overcompensating for too much weight. In any case good luck!

Yeah I noticed that even when my breathing rhythm is quite ok (around 4 sec in, 6-8 sec out), I feel that I suck lot of air during that 4sec inhale

It appears you have worked out most of the common causes of high gas consumption. I am in much the same situation. The best advice I can give you is to try to remove stress as much as possible. My consumption went up when I was leading our group and back down when someone else led. So, I started working on the stress level when leading and brought my rate back to normal. Stress adds to breathing rate, thinking about breathing rate increases breathing rate. So, stop thinking about it and start enjoying leading groups. Find positives to focus on and not negatives, this will help reduce stress and consequently your breathing rate. I now practice breathing rates out of the water and stopped worrying about it underwater. My breathing rate dropped due to muscle memory and less stress. Have fun and keep diving!

Yeah I tend to stress sometimes when I'm leading. Especially when visibility is poor, there's current and customers are not very experienced.

I've managed to drop my SAC rate to 19-20L/min in last 2 weeks, so maybe I have still hope

 

[SouthernSharktoothDiver]

Just a thought, but have you considered backmounted doubles? you could use a pair of standard AL-80's (12 L's to you non-Eaglelanders), and have plenty of air for your own use and if a customer needs to buddy breath. A bit bulkier, sure, but you're obviously strong with all the weight lifting, so I expect you could manage it well enough.

 

[Doc Harry]

250 dives?
You're still a beginner.
Keep diving.

 

[DreadnoughtNH]

I'm about your same height and weight. Like you, I've optimized my weighting, my technique, streamlining, and keep my SAC rate down. Trouble is, due to our size, we have proportionally larger muscles, larger lungs, and higher O2 consumption as a result. If you workout regularly -- particularly strength training -- it's even worse!

Simplest solution: bigger tank (100cf or 120cf). It will be proportional to your size. My friends like to joke that I carry a water heater on my back, but it's honestly not a hindrance given my size. I just make sure to bring a bungee or ratchet strap to keep it rolling around the boat since the larger diameters don't usually fit in the tank racks.

 

[scubadada]

I'm about your same height and weight. Like you, I've optimized my weighting, my technique, streamlining, and keep my SAC rate down. Trouble is, due to our size, we have proportionally larger muscles, larger lungs, and higher O2 consumption as a result. If you workout regularly -- particularly strength training -- it's even worse!

Simplest solution: bigger tank (100cf or 120cf). It will be proportional to your size. My friends like to joke that I carry a water heater on my back, but it's honestly not a hindrance given my size. I just make sure to bring a bungee or ratchet strap to keep it rolling around the boat since the larger diameters don't usually fit in the tank racks.

100s and 120s are 7.25 inches in diameter, same as an AL80. 117s and 133s are 8.0 inches in diameter.

 

[lowwall]

People overcomplicate this. Your consumption rate is the volume of your inhale multiplied by the rate of your breaths. Don't try to cut down the volume of your inhale, that leads to CO2 retention. So what is left is the breathing rate.

Breathing underwater has one tremendous advantage when it comes to breathing rate. The number of oxygen molecules in each breath is significantly larger than you get at the surface. The result of this is that if you can keep your work load reasonable, you can take fewer breaths per minute than at the surface without any concerns about depriving your tissues of the O2 they need.

But you do need to worry about CO2 buildup, so long inhales or long inspiratory pauses (holding your breath) are a bad idea.

That leaves you with the exhale. Long exhalations are the key to decreasing SAC rate while keeping CO2 under control. Breathe out slowly, really let it dribble out. You can easily take it out to 15 seconds if you are just cruising along. I can do 20 second exhales on a drift dive at depth. Remember at 20m you get three O2 molecules for every one you get at the surface.

When you are done with the exhale, don't try to lengthen the inhale, just take a nice deep breath and start your exhale again.

You said your current pattern is 4 secs in and 4 to 6 out. Make that 3 in and 12 out and you've cut your SAC rate by at least 33%.

 

[LFMarm]

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