The Science Behind Sleepwear and a Good Night’s Rest

Tossing and turning at night isn’t just a story of stress or screens—it’s also about what’s draped over the body as sleep begins. Recent science reveals that the fibers in nightwear—cotton, wool, polyester—change how quickly you fall asleep, how deeply you rest, and even your body’s internal temperature as you sleep.[1]

The Power of Fabric: Not All Nightwear Is Created Equal

Imagine slipping into cotton pajamas during a warm night. One clinical study measured young adults wearing custom-tailored 100% cotton or wool sleepwear at both 17°C and 22°C in controlled lab conditions. The result? Wool outperformed cotton by helping people fall asleep significantly faster at 17°C—about half as long![1]

·         Wool sleepwear: sleep onset latency (SOL) much shorter—9.9 minutes vs. 18.1 minutes for cotton at 17°C

·         At warmer temperatures (22°C), cotton provided slightly more deep sleep (stage N3) than wool

Why Does Fabric Matter?

Nightwear fabric isn’t simply about texture. Wool, for example, is a fiber engineered by nature to wick away moisture and insulate, keeping the body’s microclimate—the “bubble” between skin and cloth—more stable. Scientists observed that wool’s higher thermal resistance and moisture absorption make it excellent at regulating both skin and core temperature, crucial for steady sleep.[1]

·         The body needs to cool down to fall asleep; sleepwear that buffers and releases heat efficiently, like wool, supports this process.

·         Cotton, while comfortable and breathable, may provide just the right thermal insulation for deeper sleep when ambient temperatures are higher (around 22°C).[1]

The Sleep Equation: Temperature + Fabric = Sleep Quality

It’s not just about picking “soft” pajamas. This research found that the combination of fabric and room temperature is key:

·         At cooler temps (17°C), wool helps people fall asleep faster and increases restorative deep sleep.

·         At warmer temps (22°C), cotton promotes a bit more of that deep, restorative sleep.

·         The type of bedding had a smaller effect compared to sleepwear choice.

Takeaway: Outfit for Optimal Sleep

The science is clear: when choosing nightwear for women (especially for maternity and sensitive sleepers), fabric type matters—not just for comfort, but for true, research-proven deep sleep. For cold nights, opt for wool pajamas. For warmer nights, cotton might be the secret to maximizing sleep quality.

Boost your sleep quality with science—choose sleepwear that’s more than just pretty; choose what works, proven by peer-reviewed research.
Backlink for further reading:
Peer-reviewed research – The effects of fabric for sleepwear and bedding on sleep at ambient temperatures[1]

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1.       https://www.dovepress.com/the-effects-of-fabric-for-sleepwear-and-bedding-on-sleep-at-ambient-te-peer-reviewed-fulltext-article-NSS