It's fine as long as the earbud fits well. Comply foam or custom tips makes that easy. https://health.clevelandclinic.org/sleeping-with-headphones https://healt

It's fine as long as the earbud fits well. Comply foam or custom tips makes that easy. https://health.clevelandclinic.org/sleeping-with-headphones https://health.clevelandclinic.org/sleeping-with-headphones I've been sleeping with custom ear molds for five years prior to moving to noise machine earbuds. Hearing's fine as of earlier this year!