Breathing question for boffins

[Far_X]

I am sure that my breathing is using up too much air. What is the average time I should expect from a 98 cf LP tank at 2600 psi? It has improved of late but I still think that even diving Nitrox will not give me longer underneath as I use up the air too quickly. I swim (breaststroke) 4-5 times per week for over an hour at the local indoor pool wearing my swimming fins, snorkel and mask to see if that improves my breathing but I am not feeling any benefit. Physically I am getting a benefit as I am a bit overweight but that is coming down due to the regular exercise and watching what I eat.

So questions to y'all:

a) What is the ideal breathing rate with minimal activity underwater? How many seconds for one cycle of breathing (inhale/exhale)?

b) Does increasing the psi descrease the volume of air used per breath or is it just the same?

Thanks to those who answer.

 

[DMDC01]

My personal breathing cycle rate is 8 seconds in 8 seconds out. Nitrox does NOTHING for your breathing rate, only increases the amount of time available. the best thing you can do to improve your breathing rate is quit stressing over it and quit thinking about it while diving. If you just concentrate on enjoying the dive or performing whatever task you are down there for, then you will not be thinking about your breathing. If you must think about it though, the thing that helps most people is to mentally time your cycles, breathe in counting one one thousand, two one thousand, three one thousand to whatever number you are comfortable with and then pause betweend the in and out cycles ( dont hold your breathe) for 1 to 3 seconds then count down your exhalation. Hope it helps.

 

[Far_X]

Eight seconds!!! I am getting ready to inhale again after 8 seconds. Now when is a pause between inhaling and exhaling not classified as holding your breath??? I guess my newbie status is confirmed until I understand that one, huh? I'll try your method when I dive tomorrow, if I remember. Thanks

 

[pasley]

I am no expert and I am a fairly new diver myself. (3 yrs diving with only 129 dives) But from what I have learned and heard here is my $0.02 worth.

So questions to y'all:

a) What is the ideal breathing rate with minimal activity underwater? How many seconds for one cycle of breathing (inhale/exhale)?

I have no idea. I try not to think about breathing. When I don’t think about it, I breath naturally and will usually have an SAC (Surface Air Consumption Rate, which is a formula to adjust your air used to as if you had been at the surface breathing. It allows us to talk about air consumption with out having to factor in depth) of 0.43-0.45 (cubic feet per minute). When I find myself thinking about my breathing it is usually because I am not as mellow as I normally am (mask leaking, or something else causing me discomfort) and I am taking bigger breaths and forcefully blowing them out. SAC then goes to 0.5-0.57. My best ever SAC was 0.37 but that was an exceptionally mellow dive and I quite literally spent a lot of time just sitting and enjoying the ocean.

b) Does increasing the psi decrease the volume of air used per breath or is it just the same?..

The pressure of the air you receive from your second stage (into your mouth) is dependent upon the depth at the time the breath is taken. The first stage regulates the pressure coming out of the tank. At surface it reduces the pressure from 2500 PSI to what is the equivalent of 1ATA (1 Atmosphere of air pressure or normal air pressure at sea level) and at 33 FSW it delivers the air at 2 ATA (or 2x the normal sea level pressure) and so on the deeper you go.

Air consumption is a function of several factors. A search here will reveal several discussions on this as it is a common question. In general here are the items that effect your air consumption:
1. Depth. You will get longer out of a tank diving at 33 Feet or less than you will diving at 66 feet or 100 feet etc. Deeper means less time on the bottom due to increased air consumption (pressure) and of course the Non Decompression Limits too.
2. Proper Weighting. If you are too heavy, you will have to add a lot of air to your BC to compensate. This is of course air you cannot breath and then you will also have more drag with the more fully inflated BC and that means more energy to move in the water and that equals more air used too.
3. Master Neutral Buoyancy. On my dive this weekend I was standing upright about 15 feet from the bottom and 20 feet from the surface watching my dive partner. He was in constant motion, with his feet and hands waving about trying to get a picture. He dives a high pressure (3500 PSI) steel, I dive an AL80 tank. I normally have several hundred pounds of air more than he does at the end of the dive. You will dramatically improve your air consumption when you have mastered your neutral buoyancy. A lot of air is wasted inflating and deflating your BC trying to get neutral. If you are doing the yo-yo routine, bouncing off the bottom and then heading for the surface with a 20 foot swing between, then a lot of air gets wasted. Ad as short of a psst of air as you can, then WAIT. If does take a little time for the added air to affect your buoyancy. Wait about 30 seconds before you add more. Dumping air is instantaneous.
4. Streamline your gear. Don’t have stuff hanging down to damage the reef and create drag.
5. Trim. Adjust your weights so that you are swimming horizontal, If you are swimming with your body higher than your feet you are creating more surface area and drag which of course requires more energy to move through the water.
6. Park your hands. Don’t use your hands to swim. Your hands should be stowed someplace. I like under my bank at my derriere. Some place them folded at their waist. You should only move your hands to check your gauges or adjust something or maybe use your light. Nothing else. Hands are not efficient swimmers and waste energy which translates to air.
7. SLOW DOWN. Move very slowly. What is the hurry, you got someplace to go? Imitate the fish, they move very slowly unless in a flight mode and then that is a short sprint because speed waste energy. By moving slowly you will do two things A: Increase your bottom time by using less air and B: See more stuff you were just swimming past before with out seeing. If you don’t chase the fish, they will get curious and come to you.
8. RELAX. Your breathing should be natural. Do you blow hard to exhale normally? Then don’t do it diving. Do you take as big a breath as you can on land? Then don’t do in in the water. Big breaths are going to cause you to rise. That is fine if you are using your lungs (NEVER hold you breath, keep that airway open)to make minor adjustments to your buoyancy. But if that is not what you are dong, then you will be adjusting your BC to compensate, and then when you exhale, you will be adding air again. Diving is a Zen thing. I have had dive partners check to see if I was awake because I was so mellow.
9. Be physically fit. From you post you are working on it.

Last of all, is enjoy the dive.

 

[Far_X]

Hey, Melvin, thanks for the words of wisdom. A lot of what (ok, all of it, but don't grin too much) you wrote makes sense. Some of it I am doing already, like the streamlining, not using hands (much, anyway). I am diving dry at the moment and am not using a lot of air to fill the suit - small bursts. Most of it is used when I come to the surface to inflate the BC. My buoyancy is ok but when I did my first night dive in my dry suit this week, I was all over the place as I wasn't judging depth correctly. Started off holding the flashlight in my left hand and my computer was strapped to my left wrist and backup depth gauge on the SPG to the left also but the compass strapped to my right wrist. No prizes for how I am going to set up next time!! I was concerned when people were surfacing once the slack tide was lost and they had 700+ more air than I did. I didn't check to see what they started with and it could have been a lot more than me but I do know that if I don't slow breathing, then the deeper dives are going to be very short and the answer is not to take two tanks!! I shall keep in mind all that you have written and hopefully I'll be able to report that I stayed down for so much longer soon.

 

[HPT3]

Slow motion...... Pretend your in slow motion. Slow your dive down. Take everything sssssllllllllooooowwwwwlllllllyyyyy. Your not in a race when you dive. Slow fin kick, enjoy the dive, listen to your breathing, view the sites as if your in a slow motion movie.

 

[Far_X]

O.....k.....a......y mate!!! can't write much, got to dash

 

[DandyDon]

Eight seconds!!! I am getting ready to inhale again after 8 seconds. Now when is a pause between inhaling and exhaling not classified as holding your breath??? I guess my newbie status is confirmed until I understand that one, huh? I'll try your method when I dive tomorrow, if I remember. Thanks

Yeah, I wish I could do an 8 second inhale and 8 second exhale, too. Wow!

Anyway, as to " Now when is a pause between inhaling and exhaling not classified as holding your breath???" It's when you make sure that you make sure you keep your airway open. Or, really - more like when you hold your breath with your chest expansion, not by holding your throat closed! Practice that without getting the water, then when you are.

Don't pause with empty lungs! That's "skip breathing", which causes CO2 buildup, headaches, etc.

That, and a hundred dives or more...

 

[Gary D.]

Just relax. No two people have the same breathing rate and yours will change with each dive as it does normally throughout the day.

Lots of factors control the rate at which you will need O2. How relaxed are you? This will change constantly, it changes from day to day without diving. How hard or easy are you kicking? How much are you moving? How deep/shallow? How much up and down? Currennt? Temp? Surroundings. And the list can go on.

I have done way over two hours on a single 80 and have sucked the same tank dry in less than 20 minutes. Your stress and activity level have a lot to do with it.

DO NOT try skip breathing and just breathe normally. Some people skip breathe daily as a normal process but they don't notice it untill a dive. Then they try to teach others how to do it, DON'T DO IT.

It isn't the lack of O2 that's the problem but CO2 build-up that will sneak up fast and w/o warning.

As you relax your breathing will improve so don't think about it and enjoy what you went down for.

Gary D.

 

[Far_X]

I have tried the skip breathing "technique" in the pool when I go swimming - one breath for two strokes. I am taking long strokes, not continuous, and normally inhale as I bring arms and legs forward for the stroke and then exhale as I exert energy. After a few strokes of skip breathing, I began to feel light headed so I decided that it wasn't a good idea.

From what I gather, if I don't worry about it and whatever air I use, I use and as long as I am aware of the SPG then the more I dive the more air efficient I will become due to practice, practice, practice.

Thanks for everyone's advice!!!

Okay let me practice that throat open chest expansion movement!!!