There is no doubt that sleep plays a crucial role in brain health and function, and as it turns out, the gut and the brain are basically in constant communication through the gut-brain axis. More specifically, the gut in gut-brain axis refers to the microbiome, or the collection of all microorganisms like bacteria, yeasts, and fungi that live in the intestines. The gut-brain axis is a two-way communication, so not only can those little critters in the gut influence heath, but mental and emotional state of a person can impact the microbiome.