How To Protect Your Hair While You Sleep
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A: Well, I'm not qualified to address your sleep (or "lack of") issues, and I recommend you speak to your physician about possible causes for the interruption of what you imply is a recent development in your sleeping patterns.
When we toss and turn, dragging or rubbing our heads and hair across the fabric of our pillows, we can snag the cuticle layer of the hair against the fibers on the pillow. This rubbing results in roughing up the surface of the hair shaft and leads to the tangles and knots you describe. It's important that in the morning when you get ready to start your day, you use care in removing these tangles to avoid breakage. A detangling spray is a good idea, as is removing any tangles and snags before you shower or shampoo your hair.
Furthermore, if you have long hair, you should consider braiding your hair before bed. By restricting the range of movement your hair can achieve at night, you minimize the amount of damage that could occur. You can also minimize the problem by using a silk or satin pillowcase to sleep on, or a silk or satin nightcap. Nightcaps may seem old-fashioned, but served a purpose for our grandmothers.
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See also:
Silk and satin for healthy hair
Sleeping with freshly straightened hair
Why do we have to dry our hair before we go to sleep?
Is it better to wear silk or satin blouses to keep your hair as healthy as possible?