I live in Austria. Here, parents open all the windows before putting kids in bed because cold air helps everyone sleep better.

• I'm an expat living in Austria and the biggest cultural shock was something called "lüften."
• Austrians air out their rooms regularly, regardless of the temperatures outside.

As a Canadian expat living in Austria, one of the biggest cultural shocks I experienced was the Austrian's window-opening compulsions. Every day, multiple times a day, people insisted on opening all the windows to air things out. It's not just a common practice — it's a cultural obsession.

Terrified of breathing "stale air" and causing too much moisture to build up inside, people take the practice of "lüften" so seriously that it can be found written into leasing agreements as a legal requirement of renting a space.

People here air out rooms all daylong

Derived from the word for air, "lüften" is the practice of airing out a room by opening the windows in a home or building for a few minutes. This allows cool, fresh air to come in and old, stale air to flow out.

The practice speaks to how homes and buildings are constructed here in Austria. Generally very air-tight with little ventilation (air conditioning units are the exception, not the norm in Austria), lüften becomes necessary to ensure adequate airflow. Due to humans who are exhaling, sweating, cooking, showering, etc., the air in our homes can quickly fill with moisture. Opening the windows in your home or office has the benefit of replacing the moist inside air with dry, fresh air from outside.

Lüften only takes a few minutes. The idea is not to leave your windows open for endless amounts of time but rather use short bursts of airing out the room periodically throughout the day. Opening the window for five minutes is usually more than enough "lüften" time. The air inside is now fresh, the humidity levels are lowered, and everyone can breathe easily.

It's part of kids' bedtime routine

Lüften before bed is considered a vital part of the evening routine for Austrian families. Even in the dead of winter, Austrians will do something called "stoßlüften" — which directly translates to "air shock." Here, they will get as much fresh air in as possible as quickly as possible, usually achieved by opening windows on opposite ends of the room or home to create a strong cross-breeze.

Yes, lüften causes their rooms to fill with cold air, but that's exactly how Austrians prefer their sleeping conditions. In fact, many families don't just stop at lüften — they're so committed to sleeping in a cold room that some will keep the top of their bedroom window open all night long. Austrian windows open vertically and horizontally, so by keeping the top of the window open, cold air is allowed to circulate into the room at night. Some people also turn their heating in the bedroom off

Cold temperatures help sleep better

Cold can be good for sleeping. The body's natural sleep-wake cycle is initiated, in part, by a drop in our core body temperature. This drop in temperature serves as a signal to the brain to initiate the production and release of melatonin from the pineal gland. Melatonin levels then rise, contributing to the body's preparation for sleep.

Melatonin has many functions in the body, but its primary one is to regulate our sleep-wake cycle and circadian rhythm. When this hormone is produced, we start to feel sleepy, so melatonin is often called the "sleep hormone."

So, a cool room makes sense for sleep since it aligns with the body's natural bio-rhythms. The optimal sleep environment typically falls within a temperature range of 60-67 degrees Fahrenheit.

You've probably heard the stories of the Scandinavian babies who take all their naps outside in their stroller, even in the winter. Their parents swear the fresh air helps them sleep better, and they're probably right. Sleeping in a room that's been filled with cold, fresh air is a similar concept.

I worried about being cold, but that's not the case. Although the air around you is cold, your bed is not. The idea is to dress warmly, snuggle in next to your loved one, and cozy up under a thick duvet. Some people will even tuck hot water bottles under the sheets while they're getting ready for bed, just to make their sleep space feel even cozier when they get into it.