Short-term effects of menthol on walking dyspnoea in patients with COPD: a randomised, single blinded, cross-over study

Abstract

+33617916098Ethical approval and consent to participate: This study was approved by the French Ethics committee Sud-Est 6 (May 17 2018). Written informed consent was obtained from all patients.

Limitations of a 6-min walk test to assess the efficacy of menthol for breathlessness

“…We recently read the article by P rieur et al . [ 12 ] published in ERJ Open Research . We would like to thank them for their investigation on the effect of menthol-containing chewing gum on breathlessness during real-world exercise tasks using the 6-min walk test.…”

“…First, they reported that menthol reduced breathlessness by at least 1 point in 21 participants (33%) [ 12 ] and a positive effect on exercise tolerance was observed in 40 participants (63%) [ 12 ]. We request the details of the respiratory rate, inspiratory volume and oxygen saturation following the 6-min walk test in the 40 participants who showed improvement in their 6-min walk distance with menthol and the 23 participants who did not.…”

“…Second, there are two main forms of menthol, l -menthol and d -menthol, and the efficacy of the l form of menthol in breathlessness has been previously reported [ 3 – 5 ]. However, the type or the amount of menthol used in the authors’ study [ 12 ] was unclear, which prevents further clinical application. Moreover, it is unclear whether the given gum was retained in the mouth during the 6-min walk test, as the study only reports them chewing it before.…”

“…L-menthol is highly accessible and versatile. Different methods of administering menthols such as crystal nasal inhalation [ 5 ], mouth swishing of diluted solutions [ 14 ], chewing gum [ 12 ] and olfactory stimulation [ 7 , 8 , 15 ] exist, but further research is needed to determine which methods are safe and effective, and in what dosages. Moreover, the clinical application of menthol for the treatment of breathlessness on exertion in patients with chronic respiratory diseases requires further research.…”

The use of menthol for breathlessness: a hot topic full of fresh ideas

“…In our article, we stated that improvements in exercise tolerance occurred in 40 participants (63% of the population) after chewing menthol-flavoured gum [ 2 ]; however, this may have been misleading, as the improvement in exercise tolerance was not related to an improvement in walking distance but to the participant's perception of their dyspnoea. When questioned about the effects of menthol during exercise, 40 participants reported that it seemed to make the exercise easier, especially during the first 2 mins, but that the effect dissipated relatively quickly.…”