Effects of prior self-control exertion on breathing effort during inspiratory loading

Self-control reflects the effortful inhibition of attentional, behavioural, and emotional impulses to achieve a desired long-term goal. Prior self-control exertion does not affect air hunger and tolerance to progressive hypercapnia, but whether it affects the mechanistically distinct sense of breathing effort remains unknown. Fourteen healthy young adults (13 males, 1 female) initially completed three familiarisation trials comprising an incremental inspiratory pressure-threshold loading (IPTL) test, which began at a load of 10 cmH2O followed by a 10 cmH2O increase every minute until task failure. Thereafter, participants completed three experimental trials comprising IPTL preceded by rest (Control; CTRL), a congruent Stroop task (CONG) requiring no self-control exertion, or an incongruent Stroop task (INCONG) requiring self-control exertion. Breathing effort was measured at the end of each threshold load. Time to task failure during IPTL was 13% shorter in INCONG (8.60 ± 1.69min) than CTRL (9.96 ± 1.79min) and CONG (9.87 ± 1.57min) (P < 0.001). The maximum sustainable threshold pressure sustained for a full 1min was lower in INCONG (84 ± 19 cmH2O) than CTRL (96 ± 18 cmH2O) and CONG (99 ± 17 cmH2O) (P < 0.001). The rate of increase in breathing effort during IPTL was greater in INCONG (0.14 ± 0.03A.U./cmH2O) than CTRL (0.12 ± 0.03A.U./cmH2O) (P = 0.016) and CONG (0.12 ± 0.03A.U./cmH2O) (P = 0.014). Prior self-control exertion increased the sense of breathing effort and reduced time to task failure during subsequent IPTL. These findings suggest that the sense of breathing effort is modulated by state self-control.