Extreme heat has many in Hong Kong complaining of "hell-level" temperatures, sweating even with a fan on, and finding it difficult to sleep without air conditioning like former Hong Kong Observatory director Lam Chiu-ying.
So, what's the best temperature to set the air conditioner for sleeping? Experts remind us that cooling the head should be the priority when setting the AC temperature; otherwise, the body cannot truly rest. Additionally, pointing a fan directly at your body while the AC is running is actually a mistake.
Set AC to 24-25°C and Use a Blanket to Keep Body Warm
Japanese media reports that Dr. Osami Kajimoto, Director of the Tokyo Fatigue and Sleep Clinic, points out that the brain is the organ that produces the most heat and is the center of the autonomic nervous system. Only when the brain is cooled and rested can the body get sufficient rest. People tend to feel tired in summer because the brain must send numerous instructions (such as for sweating), which consumes significant energy.
The brain and body have different temperature comfort requirements: around 23°C for the brain, and around 26°C for the body. To balance both, it is recommended to:
- Set the air conditioner to 24-25°C while sleeping, with the timer set to turn off in the morning.
- The key is to cool the head while keeping the body warm. Therefore, sleep with a blanket; a thick winter blanket can be used if necessary.
Breathing Technique to Cool the Brain: Inhale for 3 Seconds, Hold for 4, Exhale for 5
The autonomic nerve center of the brain is located near the nasal cavity. The most effective way to cool it is to inhale cool, fresh air. Experts recommend this breathing technique:
- Inhale slowly through the nose for 3 seconds.
- Hold your breath for 4 seconds.
- Exhale slowly through the mouth for 5 seconds.
- Repeat 3 times to help cool the brain.
7 Tips for Better Summer Sleep
- Wear long sleeves and long pants to bed: Helps absorb sweat, allowing evaporation to regulate body temperature. Choose moisture-wicking, quick-drying fabrics.
- Avoid wearing socks: Socks hinder sweat release from the soles of the feet. Consider warm leg warmers instead.
- Do not point an electric fan directly at your body: Even if the fan oscillates, it only reaches one side at a time. This can confuse the body, causing sweat glands to shut down, hindering temperature regulation and potentially leading to insomnia. When AC is on, use the fan to circulate indoor air, not blow directly on you.
- Keep the bedroom completely dark.
- Gradually dim the living room lights before sleep (e.g., switch to warm lighting or indirect lighting).
- Avoid using smartphones after bathing, and don't bring your phone into the bath, as this can overheat the brain.
- Do not drink alcohol before bed; alcohol makes sleep lighter.
Source: MBK
