Reference; https://mbp-japan.com/jijico/articles/32459/
Modified and translated by CFJA
A Comfortable Indoor Temperature for Maintaining Body Heat: 24°C–28°C
To build a body that can cope with the cold, it is important not to expose yourself unnecessarily to cold environments.
January is a particularly cold time of year in Japan, as reflected in the seasonal terms Shokan (Lesser Cold, January 5) and Daikan (Greater Cold, January 20).
In colder regions, people generally spend the winter in well-heated rooms. However, in relatively mild climates such as Vancouver, many people appear to live in indoor environments where temperatures fall below 18°C.
Studies have shown that even when living in such cold conditions, many people do not recognize the cold, reporting that they “do not feel cold” or even feel comfortable.
Average indoor temperatures by room have been reported as follows:
- Living room: 17.7°C
- Bedroom: 13.1°C
- Changing room: 14.5°C
When a person spends long periods in a cold room, they may gradually lose their awareness of feeling cold.
Five Signs That the Body Is Not Coping Well With the Cold
- Waking at night to use the bathroom
- Leg cramps in the early morning
- Ringing in the ears (tinnitus)
- Loss of appetite
- Heaviness in the back of the head
People who experience these symptoms may not be adapting well to the cold.
Subjective sensation alone is not reliable; it is important to measure and know the actual room temperature.
The temperature setting on an air conditioner is not always an accurate indicator, as actual room temperature varies depending on the living environment. It is advisable to check the temperature about one meter above the floor.
Recommended Indoor Temperatures for Maintaining Health
- At rest: 26–28°C
(relaxing in the living room) - During meals: 22–25°C
(while eating) - During activity: 19–21°C
(housework, childcare, or other tasks) - During sleep: 18°C
(in the bedroom)
Cold can act as a silent killer, so it is important to use heating whenever room temperature falls below 18°C.
For those interested in learning more about protecting themselves from the cold, please refer to my previous blog posts.
During Winter Doyo, It Is Important to Take Measures to Prevent Low Body Temperature
As severe cold waves continue in Japan, it has been reported that six people died in Niigata Prefecture between January 21 (Wed) and January 26 (Mon), 2026.
In Niigata, the total number of casualties related to snow this season reached 64 people as of 3:00 p.m., January 26.
During the cold wave that struck North America on January 24–25, 2026, it was also reported that at least 45 people had died in the United States as of 9:00 a.m., January 28.
These figures continue to be updated as new information becomes available.
When body temperature drops too low, symptoms such as the following may appear:
- Uncontrollable shivering
- Slowed movements
- Reduced ability to think clearly
- Slower reactions
- The body feeling cold to the touch
Symptoms of low body temperature can resemble conditions that people experience in daily life, so some individuals may not realize that their body temperature has dropped.
Sleeping in a north-facing room can make it easier for body temperature to fall, so appropriate precautions are necessary.
People who sleep in cold rooms, especially those whose bodies are already weakened, often report sensations such as:
- 16–15°C: Breathing feels slightly difficult
- 14–13°C: The air inhaled through the nose feels cold
- 12–11°C: The air inhaled through the nose feels painful
- 10–9°C: Nasal congestion begins
- 8–7°C: A runny nose begins
- 6–5°C: Breathing becomes difficult
- Below 4°C: Waking up because of the cold
For individuals experiencing symptoms 1–9 mentioned earlier, or the low body temperature symptoms listed above, one important preventive measure during the Winter Doyo period is to sleep in a bedroom where the temperature does not fall below 18°C.
For those who would like more detailed information on protecting the body from the cold, please refer to my previous blog posts.