Author Topic: air consumption / headaches  (Read 2588 times)

ZombieDiver

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air consumption / headaches
« on: February 19, 2016, 18:59:56 UTC »
When I was a new diver, I would go through air pretty quickly--I never had the lowest air among the divers back on the boat after a dive but was usually pretty close.  Over time, once I got the hang of maintaining neutral buoyancy, staying streamlined, and efficient finning, my air consumption improved dramatically.  I would still use significantly more air than my wife, who is also my dive buddy, but she is smaller than me and weight and gender are factors in air consumption.  Nevertheless, I wondered if I could further improve my air consumption so she'd be able to get a full tank's worth of diving (instead of having "plenty" of air left in her tank when the volume in my tank required us to head up). 

So the last time we went on a dive trip, I started consciously focusing on the rate at which I was breathing and trying to maintain a steady rate of respiration with full breaths instead of more rapid shallow breathing.  When I did that, my air consumption plummeted.  At the end of the first such dive, I had significantly more air than my wife.  Over the next few dives, my air consumption was quite low when I focused on my breathing but creeped back up to my prior consumption level when some other aspect of the dive commanded all of my attention. 

I also started having occasional but intense post-dive headaches on this trip.  After a while I realized the headaches only occurred after dives on which I'd been particularly "good" with my air consumption. 

So here's my question- is it possible to consciously (albeit unintentionally) suppress your breathing rate to the point of causing O2 deprivation or CO2 buildup that could lead to such headaches?  I was trying to maintain a steady/healthy rate of deep breathing but would think that even if I accidentally breathed too little for a few minutes, my body would react by gasping for air or panting for breath or something (which never happened on these dives).  When I'm engaged in heavy physical exertion on land, I breathe more whether I want to or not because my body needs the air.  Wouldn't the same thing happen while diving? 

DocV

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Re: air consumption / headaches
« Reply #1 on: February 24, 2016, 14:08:06 UTC »
So here's my question- is it possible to consciously (albeit unintentionally) suppress your breathing rate to the point of causing O2 deprivation or CO2 buildup that could lead to such headaches?

Hi ZombieDiver,

It most definitely is.

"Gasping for air or panting for breath" when engaged in heavy physical exertion typically is triggered by a rapid increase in arterial CO2. The build up of arterial CO2 secondary intentionally slowed breathing during recreational diving usually is much more gradual and can thereby fail to activate the chemoreceptors responsible for activating an increase in respiration.

Make sure that you are not slowing your respiration to the point of "skip breathing." Also, make sure that your reg is in proper tune.

Regards,

DocVikingo


ZombieDiver

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Re: air consumption / headaches
« Reply #2 on: February 24, 2016, 14:33:46 UTC »
Thanks for the response and info, DocV.  While DAN publications discuss "skip-breathing" as a cause of post-dive headaches, none I've found explain why slowed respiration under water doesn't result in gasping or panting as clearly as your response did.  I don't hold my breath while diving or delay taking a breath, but it does seem like I may have been inhaling and exhaling too slowly to adequately clear C02.  I'll be diving this weekend and will try to focus less on controlling my rate of breathing and more on enjoying the dives. 

dbfeldman

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Re: air consumption / headaches
« Reply #3 on: March 16, 2016, 23:27:27 UTC »
I was interested in the reply to the question about increasing CO2. I grabbed a pulse ox in the office. My baseline was 97% at a heart rate of 88. I tried shallow slow breathing and could get down to 94% at a rate of 87 but got air hunger within a minute or so. I tried slow deep inhalations and exhalations as described. Got 97% at a rate of 87 before I felt air hunger. So I doubt the explanation given. I don't know why there was a headache but I doubt there was CO2 retention as a contributing factor.

Tom Leaird

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Re: air consumption / headaches
« Reply #4 on: May 18, 2016, 12:39:41 UTC »
I have been diving for over 50 years (3400+ dives) and have experienced the headache described above.  The explanation I have received is that an increase in CO2 retention causes tissue edema or swelling, especially in the brain.  The headache often lasts up to seven hours.  Every time the heart pumps, the swollen tissue resounds against the skull.  Three cures - 'Breathe', a strong cup of coffee some time after I recognize the effect, and I have found in recent years that using Nitrox reduces the occurrence.  I also have found that when my consumption reaches or goes below .35 cubic feet per minute - surface equivalent, that the headache is likely.  Tell yourself to keep breathing...

 

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