Cold Dew: Do you listen to the "Autumn Johns Song" or follow the "Autumn Freeze" principle?

There is a proverb that goes, "After eating the Cold Dew meal, people rarely wear thin clothes." It means that after the Cold Dew, the weather turns cold and people need to wear more clothes to keep warm. Some people say that you should wear long johns during the Cold Dew season, and they created the "Long Johns Song". There are many versions of the "Long Johns Song", and we will only look at the lyrics of two of them:

Version 1 : "I took a look at the temperature this morning and it was actually negative. I searched through boxes and cupboards for protection. Normally, I would expose myself for beauty, with three feet of cloth all over my body, but today it's too cold and I'm afraid I can't bear it... I'll be happy if I put on long johns..."

Version 2 : "...Young men should keep warm... wear long johns so you can stand out in the wind..."

As for these two "Long Johns Songs", they are to advise everyone to keep warm. We hope everyone will wear long johns to achieve the effect of keeping warm and gain a sense of happiness.

But there is also a saying called "cover up in spring and freeze in autumn", which means that when the Cold Dew comes, don't rush to wear long underwear, it's better to freeze a little. So, who should we listen to...

01 What’s the reason for autumn cold?

Autumn freezing is a health-preserving method that gradually adapts to the cold weather in autumn to enhance the body's cold resistance, regulate body functions, improve immunity and prevent diseases. It emphasizes that when the weather turns cooler in autumn, people should not add too many clothes too early, but gradually adapt to the changes in the weather in autumn to enhance the body's cold resistance and prepare for the coming cold winter.

Appropriate cool stimulation can help the human body develop the ability to tolerate cold. This kind of exercise can gradually adapt the human body to the low temperature environment and reduce the incidence of colds and other diseases caused by sudden drops in temperature.

Cold environmental stimulation can activate the activity of brown adipose tissue, increase energy consumption and metabolic rate, and promote the regulation and balance of body functions.

During the autumn freezing process, the body's contact with the cold environment will cause blood vessels to contract, promote blood circulation, and strengthen the movement and metabolism of immune cells. In addition, the cold can also stimulate the production of immune substances such as white blood cells and antibodies in the body, thereby enhancing the body's immune ability and improving resistance.

After reading the above statements, I feel that "autumn cold" still makes sense. In this case, don't rush to wear thermal underwear.

02 Temperature characteristics of the Cold Dew solar term

Whether to wear thermal underwear is a question that involves the atmospheric temperature , so we need to first understand the temperature characteristics of the Cold Dew solar term.

During the Cold Dew season, the temperature across the country generally begins to drop, marking the arrival of late autumn . At this time, people can clearly feel the change of seasons, gradually turning from hot to cool or even cold.

Image source: China National Meteorological Administration

my country has a vast territory, and the temperature characteristics of different regions during the Cold Dew season vary significantly:

Northern regions such as Inner Mongolia and Heilongjiang have entered winter or are close to winter , with temperatures generally below 10°C . Temperatures in northern Inner Mongolia, northern Heilongjiang and Qinghai are even below 5°C. Cold air masses are beginning to dominate, with a significant drop in temperature. Areas south of the Qinling Mountains, such as western Xinjiang and North China , have temperatures between 10-15°C .

In southern China, such as Guangdong, Guangxi, and Hainan , although the temperature is still around 20°C , it has dropped significantly compared to before, and the climate is cool and pleasant. In some areas of Hainan, the temperature is above 25°C and it is still summer.

During the day, the temperature is relatively high because the solar radiation is still strong; at night, the temperature drops rapidly due to the loss of heat by ground radiation, resulting in a temperature difference of 10°C or more between day and night. The temperature difference between day and night has increased significantly.

During the Cold Dew season, wind speed gradually increases, with breezes or windy weather appearing in many places, exacerbating the drop in temperature and the increase in the temperature difference between day and night.

03 Principles of wearing long johns

Having discussed this, then, should we wear long underwear or not? We must grasp some basic principles, that is, it varies from person to person, from place to place, and from weather to weather. We cannot generalize and must treat each case specifically.

It depends on the person

The elderly have a slower metabolism, which generates less body heat and a lower ability to regulate body temperature, so they are more likely to feel cold and need to wear long underwear earlier. Young people have a more vigorous metabolism, which generates more body heat and has a stronger tolerance to cold, so they don't need to wear long underwear too early.

Patients need special treatment. For example, people with leg diseases such as rheumatoid arthritis and varicose veins have increased sensitivity to cold due to the influence of the disease itself. Therefore, they need to wear autumn johns earlier to keep warm and avoid worsening of the disease.

People who often work or engage in activities outdoors need to wear long underwear earlier to keep warm because they are exposed to more cold air.

Varies by location

Although both are Cold Dew solar terms, my country has a vast territory. According to the atmospheric temperature classification standard, most parts of my country have entered autumn, but there are obvious regional differences in the speed and depth of the season. The Northeast and Northwest regions have entered late autumn or even early winter, while the southern region is still in the middle and late autumn. Tibet, Mohe and other places with winter temperatures not only need to wear long underwear, but also wear thicker long underwear to resist the cold, while Hainan and Taiwan can wear shorts without any problem.

Varies depending on weather

During the Cold Dew season, cold air activities are frequent. If a cold wave moves southward, the temperature will drop suddenly. At this time, you should wear autumn trousers in time according to the weather changes and keep warm.

Basic principles

Wearing long johns, we must master some basic principles:

As the temperature gradually drops in autumn, when you feel chilly in your legs or knees , you should put on long underwear in time to prevent the cold air from directly invading your legs and causing discomfort or illness.

When choosing long johns, you should give priority to wearing comfort . The material of long johns should be soft, breathable, and good at hygroscopicity to avoid irritation or discomfort to the skin. The size should also be appropriate, not too tight or too loose, so as not to affect blood circulation or freedom of movement.

The thickness of long johns should be selected according to the temperature changes and personal body feeling. In early autumn, when the temperature is still high, you can choose thinner long johns; as the temperature drops further, gradually change to slightly thicker long johns. Avoid wearing long johns too early or too late to maintain your body's comfort and health.

When matching trousers, you should pay attention to color coordination and style matching to avoid being too abrupt or affecting the overall image.

As underwear, autumn johns are easily contaminated with dirt such as dandruff and dust, so they should be replaced and washed regularly to keep them clean and hygienic. Especially after sweating a lot or exercising, you should change into dry autumn johns in time.

Author: Wang Yuanhong, Senior Weather and Climate Engineer

Reviewer: Tang Qin, Deputy Secretary-General of the Expert Committee of the Chinese Medical Association, Senior Researcher, National Health Science Expert

Produced by: Science Popularization China

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