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Comment by pbhjpbhj | Hacker News Reader

I was thinking about this a couple of weeks ago, expiration that is. This question raised itself and I've not focussed on answering it yet - if you breathe more then, like forced breathing, can you accelerate carbon loss [beyond that expected by the increased exercise involved in such breathing]; like fanning flames I guess.

Thinking now I suppose an [close] equivalent is probably can you increase carbon dioxide production by increasing oxygen saturation of the air inspired?

There's probably enough in that idea to sell oxygen masks and little tanks and a book for a new fad 'diet' ...

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Accelerating carbon loss through hyperventilation will make your blood alkaline, possibly to dangerous levels. https://en.wikipedia.org/wiki/Respiratory_alkalosis

Not sure that would be true... the body is producing a set amount of CO2. Breathing faster would expel it more quickly, but not change the total amount, correct?

I suppose the act of breathing itself would burn more calories, but it isn't the most challenging exercise, not to mention the dizziness mentioned already.

I'm going from a position of ignorance wrt how breathing works at the molecular level – how does the carbon arrive on site (which specific location) to combine with the oxygen, what membranes are involved, what vapour pressures and saturations might be pertinent. Ergo, I hadn't addressed the question as yet. Basically I'm asking is exertion the only limitation on the CO2 production.

[1] answers a lot of this.

Again with presumptions from biological ignorance, in low oxygen environments it seems we can't "burn" so much food, so oxygen saturation is definitely a limitation. Also we know that oxygen saturation varies, so even if STP oxygen percentage of air is the optimum sometimes we'll be sub-optimal - how does the body cope then?

[2] appears to answer that one.

What I take away from that, wrt my enquiry, is that under increased breathing [hyperventilation] renal compensation can kick in to combat the alkalemia caused by the respiratory alkalosis [reduction of available H+ ions in the blood, ie alkalination or increasing of pH] by extracting extra-cellular fluid bicarbonate [HCO3-, see [3]] and excreting it in urine.

Now I'm moving back up the pathways, is renal compensation deleterious (and at what point is that true). Does low level alkalosis with renal compensation cause an increase in removal of food products from the body?

At least it seems that we now have created an increased carbon removal by excreting HCO3- in urine!? [how much?]

So is there an increase in breathing frequency that maintains normal function, not "hyperventilating" (in the common usage of the term, that makes you dizzy), that doesn't cause harm? The question still stands I feel.

Also can you do something else that causes acidosis and cancel it out by increased breathing?

Apologies again, I'm clearly fumbling around here but I've not studied biology since I was 13 (decades ago).

- - -

[1] https://en.wikipedia.org/wiki/Respiratory_acidosis#Mechanism

[2] https://en.wikipedia.org/wiki/Metabolic_alkalosis#Compensati...

[3] http://web.archive.org/web/20070930080050/http://www.lib.mcg..., via Wikipedia https://en.wikipedia.org/wiki/Renal_compensation

> oxygen percentage of air is the optimum sometimes we'll be sub-optimal - how does the body cope then?

I think altitude sickness would be the result, not enough oxygen.

Try exercising. Apparantly it will make you breathe more heavily.

I believe that encouraging aerobic respiration (maintaining high levels of O2) would be less efficient if your goal is weight loss.

When your cells are breaking down sugar into energy, if you have enough oxygen readily available then you can extract more energy per molecule of sugar. If you're burning sugar anaerobically, then you won't be able to make the full use of the sugar, and thus the byproducts will get excreted with less work required.

Are you talking glycolysis there?

>the byproducts will get excreted //

How?

Correct.

Also, I was mistaken somewhat, the byproducts aren't excreted, they're reprocessed in the liver back into glucose, but this requires extra energy. So it's less efficient than aerobic respiration, but not by as much as I believed.

It's not a good idea.

http://en.wikipedia.org/wiki/Oxygen_toxicity

I think oxygen toxicity is pretty well know, what I was musing over was whether through a slightly elevated breath frequency, or slightly deeper breathing, one could have more oxygen available and so increase CO2 production. If instead of 100% oxygen one breathes 22% (vs. 20% in normal air IIRC), what then?

Someone else has noted respiratory alkalosis as a limiting factor, but that again is seemingly an extreme.

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