Comments to Nordmo et al.'s article: effect of hardiness.

We would like to comment on Nordmo et al.'s article on hardiness among Norwegian Royal Navy seamen. The article is very interesting. Understanding the sleep disorders of the military can indeed make it possible to favour the preservation of their health and their competencies. The authors have highlighted the limitations of their study. They will take into account the sleep disorder factors already described in literature, such as: noise, comfort on board, shift organisations, etc. We would like to make two comments: on the one hand, highlight another limit to help future studies; on the other hand, open another perspective of prevention, not described in this article.