Bicarbonate loading doesn't help, because it inhibits the bohr effect. You need acidic blood to stay conscious; the O2 affinity of hemoglobin decreases with increasing blood acidity, and that keeps you conscious. If you artificially alkalinize your blood by either electrolyte drinks or hyperventilation, then you make your blood too alkaline to maintain consciousness. It is true that both bicarbonate/citrate and hyperventilation make holding your breath EASIER, but in the end you will black out SOONER than if you left your body alone. However, beginners who do not have the willpower to hold their breath to the point of blackout will always benefit from those techniques because they are not reaching a level of hypoxia where blood acidity is important.
As an example, if you decrease the O2 fraction in air, the blood remains alkaline (no CO2 build up), but you blackout around SaO2 = 55-70%. However, in the presence of CO2 build up, some freedivers get down below SaO2 = 20% without loss of consciousness or motor control; why? Only because the acidity is keeping them conscious.
Martin Stepanek does not hyperventilate for his world record level statics. He gets contractions around 4:00 - 4:30 and forces himself through 4 or more minutes of contractions. His ability to resist the huge CO2 is what keeps him conscious.
Eric Fattah
BC, Canada
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