On hot summer nights, it feels natural to open the window in search of cooler air.
But according to experts, this habit might be doing more harm than good - especially if you live in an urban area.
Here’s what you risk when sleeping with the window open and what you should do instead for restful sleep.
Street noise disrupts sleep quality

While fresh air seems like a good idea, urban environments are filled with nighttime noise from traffic, sirens, and people.
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A study from Germany shows that persistent street noise increases cortisol levels, the body’s main stress hormone, making it harder to fall into deep sleep and stay asleep.
Higher stress levels during the night

Even if you're not fully awake, constant background noise during sleep keeps your stress levels elevated.
This not only leads to poor-quality sleep but also impacts your body’s ability to recover and reset overnight.
Weakened immune system

Poor sleep affects your immune function. Without enough deep sleep, your body can't produce the cells and proteins needed to fight off viruses and bacteria, leaving you more susceptible to illness over time.
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Overheated rooms cause restless nights

The body needs to cool down slightly to fall asleep.
If your bedroom is too warm, your body can't regulate temperature properly, leading to restless or superficial sleep.
Experts recommend keeping the room between 18°C and 22°C.
Wrong bedding materials trap heat

Synthetic sheets and bedding retain heat and moisture, making summer nights even more uncomfortable.
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Natural materials like cotton or linen allow your skin to breathe and absorb sweat, improving overall sleep comfort.
Wearing the wrong sleepwear

Thick or synthetic sleepwear prevents your body from cooling down naturally.
Loose-fitting cotton pajamas are the best choice during warm nights to keep your body temperature in check.
Cold drinks and alcohol make things worse

It might be tempting to down an ice-cold drink before bed, but very cold liquids can shock your system and disrupt your body’s temperature regulation.
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Alcohol may seem relaxing, but it fragments your sleep and can cause multiple awakenings.
Heavy evening meals raise body temperature

Eating a large meal just before bed kickstarts digestion - a process that generates heat.
This can make it harder to fall asleep and may cause indigestion or acid reflux. Opt for a light snack like yogurt or fruit instead.
No cooling routine before bed

A lukewarm or slightly cool shower before bed can help lower your body temperature and prepare you for sleep.
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As the water evaporates from your skin, your body cools naturally - signaling to your brain that it’s time to rest.
Too much water before bed leads to sleep interruptions

Staying hydrated is crucial in summer, but drinking too much water right before bedtime can lead to frequent trips to the bathroom.
This interrupts your sleep cycle and lowers sleep quality.
This article is based on information from Dcnews.ro.