What is this ancient wellness device? This large cylindrical bamboo object is called a bamboo wife. Koreans have been using it to keep cool at night for thousands of years.
Heat bothers us not only during the day but also at night. The hotter it is, the harder it is for us to fall asleep and sleep soundly. In addition to light cycles, our body is also regulated by temperature. To fall asleep quickly, we must cool down and shed excess heat. The temperature should also change during different phases of sleep. Core temperature generally needs to drop before you can reach the state of deep sleep. If your core temperature is too high, however, it is complicated for your brain to tell if you’re awake or asleep, which may directly affect the quality of your sleep. High temperatures can increase arousal and decrease slow-wave sleep (“deep sleep”), the physically restorative stage of sleep.
For an adult, the optimal temperature is 16–20 degrees Celsius, and anything above 24 degrees negatively affects sleep quality. Increased outdoor temperatures are linked to lower sleep duration. Nighttime temperatures higher than 25°C were linked to 14 minutes less sleep. Due to global warming, temperatures are only rising, causing sleep quality to decline. A bad night means a bad day, affecting everything from productivity to cardiovascular health.
So, what do you think can be done?
- Drink more water and maintain good sleep hygiene.
This includes darkness, silence, limiting caffeine, alcohol, and heavy meals. The combination of multiple irritants worsens sleep more than just one. Adequate hydration is essential (monitor thirst and urine color).
2. Keep your bedroom cool.
Choose the coolest room for sleeping (ground floor or north-facing room), and avoid heating the room during the day (use shutters or curtains).
3. Cool the bedroom.
Air conditioning is the most effective and expensive method, but a regular fan can also improve heat exchange. Special passive cooling systems that combine wind and water power are also available, though they require specific efforts (which might interest engineers!).
4. Use natural fabrics with high thermal conductivity.
Sleep without clothes and use bedding made from natural fabrics with higher thermal conductivity. Note that there are special mattresses and pillows with enhanced thermal conductivity.
5. Local cooling. Cooling sheets or pillows can help, and special gel inserts can be inserted into them. A damp cloth on the forehead or wet hair can also help. A warm shower before bed can help shed excess heat.
6. Keep your distance and spread out.
You can heat yourself up. Therefore, sleep with your arms and legs spread out and a bit farther from your partner. The bamboo wife in the picture solves this task precisely.
Rising temperatures erode human sleep globally Volume 5, ISSUE 5, P534–549, May 20, 2022
Thermal environment and sleep quality: A review Energy and Buildings Volume 149, 15 August 2017, Pages 101–113