Menthol for exertional dyspnoea relief in COPD

Menthol inhalation relieves dyspnoea during loaded breathing in COPD and during exercise in healthy adults, respectively. We still do not know if menthol can also improve exertional dyspnoea in COPD. Sixteen COPD patients (56%male, 68±7yrs, FEV₁ 47±17%predicted) performed 2 constant-load cycle exercise tests (74±7%peak power) to exhaustion while inhaling menthol or placebo (strawberry) in random order on separate days. Dyspnoea was serially assessed using the 0-10 Borg scale. Participants were asked in which test their airflow felt easier on inspiration. Dyspnoea ratings were lower with menthol <italic>vs</italic>. placebo over exercise time (Fig 1A; <italic>p</italic>=0.007). Iso-time dyspnoea was 1.0±2.3 Borg units lower with menthol (<italic>p</italic>=0.10; Fig 1B), which correlated with changes in endurance time (<italic>r</italic>=-0.69, <italic>p</italic>=0.003; Fig 1C). However, there was no effect of menthol on ventilation over time (<italic>p</italic>=0.98), and exercise endurance was not different between conditions (Δ0.1±1.4min with menthol, <italic>p</italic>=0.85; Fig 1D). 81% reported higher perceived inspiratory airflow with menthol. While improvements in iso-time dyspnoea were variable and not statistically significant, the average change attained the minimal clinically important difference of 1 Borg unit and was associated with improved exercise tolerance. In selected COPD patients, menthol inhalation may therefore be useful for exertional dyspnoea management. Future work should investigate if menthol can enhance the benefits of an exercise rehabilitation program. <fig><object-id>erj;64/suppl_68/OA1881/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>