Excessive friction and movement while you sleep can cause tangling, breakage, and shedding in your hair system. For most, this is not a problem. However, the longer your hair is, the more prone it is to damage. In order to protect your hair system, there are some preventative measures you can take before going to bed each night.
Use silk, satin, or high-thread-count Egyptian cotton pillowcases that will not absorb moisture from your hair, causing it to dry out and tangle or mat while you sleep. These fibers do not catch or pull on the hair cuticle like traditional cotton can. Do *not* sleep with a flannel pillowcase, as this causes excessive drying, tangling, and breakage, especially in longer hair.
If you have long hair
To protect long hair, at the very least be sure to spray on leave-in conditioner before bed. Then, to further prevent tangling, braid your hair or wear it in a side ponytail. This step is especially important if you have curly hair. Another option for curly hair is to use a scrunchie to hold the hair on top of your head in a loose ponytail, so you don’t crush or frizz your curls while sleeping. Ultimately, the best protection for your hair is to sleep in a silk head scarf or sleep cap.