How "much" of air consumption is physiology? How to improve consumption?
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Most of my dives are in pretty warm water with a few colder dives in California, Galapagos, etc. My average RMV for my last 1400+ dives is O.36 +/- 0.04 cu ft/min (mean +/- std dev). I have just under1900 dives, my RMV has improved only a little in the last 9-10 years.
FreeFlyFreak
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5'10" 185 lbs. My best is 0.27 cu ft/min on a couple of dives
FreeFlyFreak
Contributor
Looks like I have some work to do.
That's what I use lying on the bottom watching the Manta's at night.
I also am built like a linebacker (6'4", 235#, weightlifter), and linebackers simply are not very hydrodynamic. We have to push a bigger frame through the water and we engage bigger muscles to do it, which requires more blood to flow and more air to get consumed.
For my first few dozen dives, I was a voracious consumer of air. Now, after 100 dives, I'm at the "pretty good for a big guy" stage. I'm never the one whose consumption dictates the end of the dive, and my dives now end either because I've completed the planned dive time or because somebody else reached an agreed-upon threshold. The tiny people and the extremely graceful divers of all sizes still use way less air than I do, but my consumption rate has significantly improved.
At first, I resorted to cheap tactics like orally inflating my BC on the boat, using my snorkel at the surface until the last possible second, and being the last in my group to descend--none of that stuff made a bit of difference.
What finally did make a difference was making more dives and becoming a better diver--basically doing everything RyanT and Tippytoes12 said.
Beyond that, I have a few suggestions:
First, be completely calm and relaxed before you enter the water and before you descend. I used to burn through a couple hundred PSI almost immediately at the beginning of the dive just from being excited about what I was doing. Assemble and check your gear early and slowly. Get the heart and breathing rates down before you splash and again before you descend.
Second, recognize that working on trim, weight and buoyancy control may even more important for us than for little people because we simply can't afford to make ourselves even a tiny bit less hydrodynamic than we already are.
Third, we also have to work harder at not working because our muscles are bigger. I try hard not to make any sudden movements. When I need to consult my computer or reach for gear or turn my head to see what my buddy is pointing at, I do it with exaggerated slowness. I also look for every chance not to kick at all. If other divers are milling around, I just hang in the water, not moving at all. Go slower. Breathe slower. See more.
Finally, I also take advantage of one factor we do have in our favor. Because I am a big guy, I don't need as much thermal protection as the skin-and-bones types. I usually wear a wetsuit at least one notch thinner than my scrawny companions do. This allows me to avoid the bulk of the extra couple mils spread over the vast acreage of my body's surface area, and it means I don't need extra weight to offset the extra neoprene. Don't go too far with this idea: diving while cold is no fun, and shivering people consume a lot more air (and make worse decisions). But don't wear any more thickness than you need.
It will get better as you dive more.
Best wishes,
For my first few dozen dives, I was a voracious consumer of air. Now, after 100 dives, I'm at the "pretty good for a big guy" stage. I'm never the one whose consumption dictates the end of the dive, and my dives now end either because I've completed the planned dive time or because somebody else reached an agreed-upon threshold. The tiny people and the extremely graceful divers of all sizes still use way less air than I do, but my consumption rate has significantly improved.
At first, I resorted to cheap tactics like orally inflating my BC on the boat, using my snorkel at the surface until the last possible second, and being the last in my group to descend--none of that stuff made a bit of difference.
What finally did make a difference was making more dives and becoming a better diver--basically doing everything RyanT and Tippytoes12 said.
Beyond that, I have a few suggestions:
First, be completely calm and relaxed before you enter the water and before you descend. I used to burn through a couple hundred PSI almost immediately at the beginning of the dive just from being excited about what I was doing. Assemble and check your gear early and slowly. Get the heart and breathing rates down before you splash and again before you descend.
Second, recognize that working on trim, weight and buoyancy control may even more important for us than for little people because we simply can't afford to make ourselves even a tiny bit less hydrodynamic than we already are.
Third, we also have to work harder at not working because our muscles are bigger. I try hard not to make any sudden movements. When I need to consult my computer or reach for gear or turn my head to see what my buddy is pointing at, I do it with exaggerated slowness. I also look for every chance not to kick at all. If other divers are milling around, I just hang in the water, not moving at all. Go slower. Breathe slower. See more.
Finally, I also take advantage of one factor we do have in our favor. Because I am a big guy, I don't need as much thermal protection as the skin-and-bones types. I usually wear a wetsuit at least one notch thinner than my scrawny companions do. This allows me to avoid the bulk of the extra couple mils spread over the vast acreage of my body's surface area, and it means I don't need extra weight to offset the extra neoprene. Don't go too far with this idea: diving while cold is no fun, and shivering people consume a lot more air (and make worse decisions). But don't wear any more thickness than you need.
It will get better as you dive more.
Best wishes,
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Yeah. I don't think my consumption rate has changed much, if at all, since my first dives. I don't think I was doing a lot of unnecessary movements, etc. and wasn't overweighted. Maybe all that snorkeling for decades before helped. I just don't think about breathing, but am well aware of how quickly a tank empties if you are swimming fast to cover a lot of ground (which I rarely do).
Oh, maybe I missed something-- according to the old tables, the Air limit at 60' is 55 minutes, so I hope you hour guys are doing deco stops. It's probably not a good idea to push it to like, 54 minutes either.
- Messages
- 19,775
- Reaction score
- 18,635
- Location
- Philadelphia and Boynton Beach
- # of dives
- 1000 - 2499
- Messages
- 16,402
- Reaction score
- 5,219
- # of dives
- 1000 - 2499
Well yeah, but they're all talking air.
Time and experience will have the most beneficial effect on your SAC rate. I've seen people who look like they'll suck air down, seem to sip on their tanks, and vice versa. Often, we're anxious and we don't realize it - but anxiety seems to suck my air the fastest, followed closely by working hard in current.
In a few years, I hope you do a search for this thread and enjoy reading how much you have improved.
In a few years, I hope you do a search for this thread and enjoy reading how much you have improved.
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