Feasibility and acute physiological responses to supramaximal high-intensity interval training in COPD: a randomised crossover trial.

Background: Extrapulmonary manifestations, including cognitive impairment and reduced muscle and cardiovascular function is common in COPD. While high-intensity exercise offers extrapulmonary benefits, its implementation in COPD is challenging. This randomised crossover trial examined the feasibility and physiological responses of a novel supramaximal high-intensity interval-training (SupraHIIT) protocol compared with moderate-intensity continuous training (MICT) in people with COPD and matched healthy controls (HCs).

Methods: 16 people with COPD and 16 HCs performed SupraHIIT and MICT. SupraHIIT consisted of ten 6-s intervals at ≈150% and ≈200% of maximum aerobic power (MAP), while MICT was performed for 20 min at 60% of MAP. Outcomes were exercise intensity, change in exerkines, feasibility and cardiorespiratory demand of the modalities.

Results: SupraHIIT was feasible and enabled up to a 3.5-fold increase in external exercise intensity compared with MICT (184±66 and 245±88 versus 71±22 W in COPD; p<0.001). All participants could complete SupraHIIT, which was the preferred modality in both groups (p<0.01), whereas 5 of 16 participants with COPD interrupted MICT due to intolerable dyspnoea or exhaustion (p=0.005). Both modalities increased plasma brain-derived neurotrophic factor (pBDNF) by an average of 59% (range 30-87%; p<0.05). When normalised for duration at target power, SupraHIIT produced a 5-10-fold greater increase than MICT. Both modalities lead to a variable response in other exerkines including clusterin, lactate, hepatocyte growth factor and interleukin-6.

Conclusion: In COPD, short-duration SupraHIIT is more feasible and enables markedly higher external exercise intensities than MICT. By elevating pBDNF and other potentially beneficial exerkines, it shows potential for extrapulmonary benefits.