High-intensity interval training (HIIT) represents a potent stimulus to the dynamic oxygen uptake (V[Combining Dot Above]O2) response in adults but whether the same is evident in youth is unknown. HIIT has also been suggested to place a lower demand on the respiratory system, decreasing the likelihood of exacerbation in those with respiratory conditions, such as asthma.
Sixty-nine adolescents (13.6±0.9 years; 36 asthma) took part, 35 of which (17 asthma) participated in a 30-minute HIIT intervention three-times/week for six months. Each participant completed an incremental ramp test to volitional exhaustion and three heavy-intensity constant work-rate tests to determine the dynamic oxygen uptake (V[Combining Dot Above]O2), heart rate (HR) and deoxyhaemoglobin ([HHb]) response at baseline, mid-intervention, post-intervention and at a three-month follow-up.
There was no influence of asthma at baseline or in response to the intervention. Participants in the intervention group demonstrated a faster V[Combining Dot Above]O2 time constant (τp) post-intervention (intervention: 29.2±5.7 vs. control: 34.2±6.5 s; P=0.003), with these differences maintained at follow-up (intervention: 32.5±5.5 vs. control: 37.3±8.7 s; P=0.008). The intervention was associated with a speeding of the [HHb] τ (Pre: 20.1±4.7 vs. Post: 18.2±4.1 s; P=0.05), compared to a slowing over the same time period in the control participants (Pre: 17.9±4.9 vs. Post: 20.1±4.6 s; P=0.012). HR kinetics were not altered (Pre: 46.5±12.2 vs. Post: 47.7±11.1 s; P=0.98).
These findings highlight the potential utility of school-based HIIT as a strategy to enhance the V[Combining Dot Above]O2 kinetics of youth, regardless of the presence of asthma.