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There are a few golden rules when it comes to beauty—among them, removing your makeup before bed and wearing SPF on a daily basis. But when it comes to hair, we tend to push our limits in ways we don't with skincare (think: delaying your trims and over-using hot tools). One common habit that can damage your hair is sleeping on it while it’s wet. Whether you tend to take your showers at night or you like to braid your wet hair at night to reveal mermaid-like waves come morning (guilty), one thing is for sure: Your hair is weakest when it's wet, which makes the way you treat it while it's in this state matter more. You should go to bed with completely dry hair if you want to keep your strands as healthy as possible, according to Chaz Dean, United States-based hairstylist and founder of WEN Haircare. Keep scrolling to learn why.

1. Sleeping with wet hair can lead to tangling

Bradford Telegraph and Argus: Sleeping on wet hair can cause tangles in your hair that lead to damage. Credit: Getty Images / NaturecreatorSleeping on wet hair can cause tangles in your hair that lead to damage. Credit: Getty Images / Naturecreator

The hydrogen bonds (the bonds responsible for our hair's shape) in our hair rebond to whatever shape they're left in as they dry. This is why leaving wet hair in hot rollers until it dries to create curls. As your hair dries overnight, its hydrogen bonds are constantly rebonding as you toss and turn, taking on various shapes as it's left to dry in the multiple positions you sleep in. The results? Tangles galore. And, Dean notes that fine hair is more susceptible to tangling. This is because having fine hair doesn't necessarily mean that you have less hair on your head—instead, it indicates that your individual hair strands are thinner than other hair types. This means that there's room for more of it, which means there are more possibilities of tangling.

2. Sleeping with wet hair can cause breakage

Bradford Telegraph and Argus: Sleeping on wet hair can lead to breakage and split ends. Credit: Getty Images / Monthira YodtiwongSleeping on wet hair can lead to breakage and split ends. Credit: Getty Images / Monthira Yodtiwong

Hair breakage refers to damaged hair that splits at the end or breaks off in the middle of the shaft. While there are a number of reasons hair can break, sleeping with wet locks is a big culprit. Dean explains that our hair is at its most fragile state when it's wet. This is because our hair forms weaker hydrogen bonds when it's wet than when it's dry. He also notes that typical movements that occur as we sleep can contribute to breakage, too. "As you're tossing and turning at night, your hair is rubbing against the pillowcase, which can cause your hair to break and make your hair appear frizzy," he says. Breakage is especially an issue if you tend to tie your wet hair into a tight bun or braids while sleeping, as this adds more pressure to the scalp.

3. Sleeping with wet hair can increase bacterial growth

Bradford Telegraph and Argus: Laying on your pillow with wet hair can cause bacteria to build up inside the pillow and its case. Credit: Gettty Images / chingyunsongLaying on your pillow with wet hair can cause bacteria to build up inside the pillow and its case. Credit: Gettty Images / chingyunsong

Just like a wet sponge harbours bacteria, wet hair can, too. Dean explains how water from your wet hair mixed with the warmth from your body creates the perfect breeding ground for bacteria. "While our scalp is home to a large number of microbes that are harmless, there are some fungi that can be damaging to the hair follicle and cause irritation, dryness, itchiness, and flakes," he says. "This is more crucial with people that have thick, coarse, textured hair because it takes much longer for their hair to dry." What's more, the dampness from your hair can also seep into your pillowcase and pillow, which creates more of a warm, humid environment that can lead to an increase of bacterial growth in those, too. If sleeping with dry hair is not an option, make sure you're washing your pillows and pillowcases every few days to ensure they aren't harbouring any fungi or bacteria.

How to protect your wet hair from damage

If you're discouraged at the thought of suddenly changing your hair washing routine, don't fret. "While it’s ideal to go to bed with the hair dry, if that isn’t possible, try to at least reduce the wetness of the hair by letting it air dry for as long as possible," says Dean. "The safest rule is to have hair 80% or more dry, as well as using a gentle hair accessory, pillowcase, and products." He recommends avoiding drying scrunchies and terry cloth-like texture pillowcases that are marketed as safe for sleeping on wet hair for their absorbent properties, as these textures can be abrasive on the hair. Instead, he suggests a silk pillowcase, a microfiber tapered hair towel, and coiled hair ties, as these are all gentler on wet hair.

Sleep on a silk pillowcase

Bradford Telegraph and Argus: Consider sleeping on the Alaska Bear Natural Silk Pillowcase to minimize friction between your hair and the pillow. Credit: Reviewed / Jackson RuckarConsider sleeping on the Alaska Bear Natural Silk Pillowcase to minimize friction between your hair and the pillow. Credit: Reviewed / Jackson Ruckar

The Alaska Bear Natural Silk Pillowcase brings new meaning to the term "beauty sleep." It's made out of high-grade mulberry silk and, unlike cotton pillowcases (which are very absorbent and can "pull" at the hair as you sleep), it creates less friction between your hair and the surface it rests on. Plus, silk pillowcases are known to have skincare benefits, too, like preventing moisture loss.
Get the Alaska Bear Natural Silk Pillowcase on Amazon for £22.99

Sop up water with a microfiber hair towel

Bradford Telegraph and Argus: Wear this microfiber Turbie Twist on your head to sop up water quickly. Credit: Turbie TwistWear this microfiber Turbie Twist on your head to sop up water quickly. Credit: Turbie Twist

In a rush? Pop on a Turbie Twist. It's an alternative to towel-drying your hair that's made out of absorbent, gentle microfiber material. It has over 1000 5-star reviews on Amazon, with fans of it raving that its lightweight feel and soft texture quickly dries the hair and minimizes breakage.

Get the Turbie Twist (2-pack) on Amazon for £18.99

Pull back your hair with a tie that's tangle-free

Bradford Telegraph and Argus: Tie your hair up with the Kitsch Spiral Hair Ties to avoid knots and tangles. Credit: KandditTie your hair up with the Kitsch Spiral Hair Ties to avoid knots and tangles. Credit: Kanddit

If your hair is prone to tangles, consider trying coiled hair ties like these spiral ones. Because they're made of plastic coils, they don't sit flush around the hair and are less likely to cause unruly knots, breakage, and ponytail bumps (especially if you tie it loosely at the nape of your neck).

Get the Kanddit Beauty Spiral Hair Ties on Amazon for £5.99

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