Hypnotic and Nonhypnotic Control of Ventilation

Abstract The present study examined the effects of: 1) breathing air versus breathing 5% CO2; 2) waking versus self-hypnotic conditions; and 3) neutral versus reduced respiratory rate instructions on four measures of ventilatory functioning (respiratory rate, tidal volume, expired minute ventilation, and end-tidal Pco2). Twelve high-hypnotizable normal volunteer subjects were studied in a repeated-measures, multivariate analysis of variance design. Significant main effects were observed for each experimental condition, whereas none of the two or three way interactions proved noteworthy. Breathing 5% CO2 produced increased ventilatory functions (e.g., increased respiratory rate, tidal volume, expired minute ventilation, and end-tidal Pco2). Being in a state of self-hypnosis is associated with reduced respiratory rate, with a significant increase in expired minute ventilation and end-tidal Pco2, but with no significant increase in tidal volume. Finally, reduced respiratory rate instructions were effective in significantly reducing respiratory rate and expired minute ventilation when breathing 5% CO2 as evidenced by increases in end-tidal Pco2 levels that were used to monitor ventilation outcomes.