Perceptual and prefrontal cortex haemodynamic responses to high-intensity interval exercise with decreasing and...

Affect experienced during high-intensity interval exercise (HIIE) is dependent on work-intensity, but the influence of increasing (low-to-high (L-H)) or decreasing (high-to-low (H-L)) work-intensity during HIIE remains unclear in adolescents. The role of prefrontal cortex haemodynamics in mediating changes in affect during HIIE also remains unexplored in adolescents. We examined affect, enjoyment and cerebral haemodynamic responses to HIIE with increasing or decreasing work intensities in adolescents.

Participants (N = 16; 8 boys; age 12.5 ± 0.8 years) performed, on separate days, HIIE cycling consisting of 8 × 1-min work-intervals at 100%-to-70% (HIIE_H-L), 70%-to-100% (HIIE_L-H) or 85% (HIIE_CON) peak power separated by 75 s recovery. Affect, enjoyment and cerebral haemodynamics (oxygenation (∆O₂Hb), deoxygenation (∆HHb) and tissue oxygenation index (TOI)) were recorded before, during, and after all conditions.

Affect and enjoyment were lower during HIIE_H-L compared to HIIE_L-H and HIIE_CON at work-intervals 1 to 3 (all P < 0.043, ES > 0.83) but were greater during HIIE_H-L than HIIE_L-H and HIIE_CON at work-interval 8 (all P < 0.048, ES > 0.83). ∆O₂Hb was similar across conditions (P = 0.87) but TOI and ∆HHb were significantly greater and lower, respectively during HIIE_H-L compared to HIIE_L-H and HIIE_CON at work-interval 8 (all P < 0.039, ES > 0.40). Affect was correlated with TOI (all r > 0.92) and ∆HHb (all r > -0.73) across conditions.

HIIE_H-L offers advancement to the HIIE_CON and HIIE_L-H which bring significant greater affect and enjoyment towards the end HIIE work-interval, implicating the feasibility and adoption of this protocol for health promotion in youth. Also, changes in prefrontal cortex haemodynamics are associated with the affect during HIIE.