A cold wave suddenly hits, why are some people more resistant to the cold than you?

In addition to the new coronavirus, another topic we discussed these two days is the "super-cold wave". Although many people yearn for this round of cold waves to bring snowfall at the end of the year and the beginning of the next year, we still need to pay attention to the natural disasters and diseases caused by the cold wave. This round of cold waves is coming fiercely. It is understood that the greater the temperature drop in autumn and winter, the busier the orthopedic doctors in the hospital will be. The most intuitive feeling brought by the cold wave is cold. Why are some people more afraid of cold? There are differences between men and women in resisting the cold. This article will explain one by one.

Today, orange cold wave warnings have been issued in many parts of the country, and snow has begun to fall in many places. Are you ready for your long johns?

As winter approaches, the weather becomes colder and colder. Even though almost everyone has wrapped themselves in warm clothes, you can still hear people shivering from the cold from time to time. Some people seem to be "born" to be more afraid of the cold than others. What's more, some people feel cold no matter what weather or season it is - and there is actually a fundamental scientific reason behind this.

We know that the average human body temperature is around 36.5°C, and this value has been decreasing by 0.03°C every decade since it was first recorded in 1851. But the interesting thing about human body temperature is not just that it is getting colder.

First, within 24 hours a day, body temperature is a value that changes constantly, with a difference of up to 0.5°C. In terms of resting body temperature, it reaches its peak around 6pm and drops to its lowest around 4am. Secondly, different parts of the body also have different temperatures.

The results of a 2019 study showed that the highest temperature is in the rectum - between 36.3-37.8°C, followed by the eardrum (35.8-37.5°C), urine (35.6-37.6°C) and mouth (35.0-37.4°C). The armpit, which is commonly used to measure body temperature, is the coldest part of the body - with a temperature range of between 35.0°C and 36.9°C.

Scientists believe that the following four factors affect our body temperature and may also be the reason why some people are always afraid of cold.

01
Anatomy Men and women have different resting basal metabolic rates (how much energy they use while at rest) and fat distribution, so they produce different amounts of heat to keep their bodies warm.

First, on average, men have a higher resting basal metabolic rate than women. Studies have found that men have significantly more muscle mass, both in absolute terms and relative to body weight, and therefore naturally generate more heat to keep warm.

At the same time, the fat layer that protects against cold and maintains body temperature is distributed differently in men and women. The subcutaneous fat in women's arms and legs is twice as thick as that in men, so it is more difficult, or takes longer, for heat from the muscles to reach the temperature receptors in the skin. This characteristic may explain why women feel cold more often on average. At present, scientists are not sure whether this fat distribution in women can keep them warmer longer once they are at a comfortable temperature.

02
Compared with men, women's basal body temperature changes periodically under the influence of a series of hormones related to menstruation. For example, before ovulation every month, the average female body temperature is 35.9℃, but it can reach up to 36.7℃ a few days after ovulation.

Some sex hormones also interact with the body's temperature-regulating system. For example, estrogen increases vasodilation, which helps lower body temperature, while progesterone raises body temperature. Studies have shown that artificial progesterone in oral contraceptives can cause users to maintain a higher temperature for a long time.

Although higher testosterone levels in men do not appear to directly change body temperature, they may reduce men's ability to sense cold by increasing the sensitivity of a receptor used to detect cold.

03
Health conditions Reduced or increased cold tolerance has also been associated with some diseases and medical conditions, common examples being Raynaud's disease and hypothyroidism.

Raynaud's disease, also known as limb artery spasm, is a condition that is more common in women and people who live in cold environments. It causes certain parts of the body (especially the fingers and toes, but can also affect the ears, nose and nipples) to become cold and numb.

Some common symptoms of Raynaud's disease: the skin may turn pale (top) due to restricted blood flow; sometimes the skin may turn blue (middle) due to the reaction of the blood vessels; the skin may turn red (bottom) when the blood returns. | Image source: nhs.uk Usually, although the patient does not feel cold all over, the affected area may have severe pain. This phenomenon occurs because the small blood vessels in the area where such symptoms occur quickly constrict. This symptom can be improved by avoiding cold and avoiding stimuli such as anxiety and tension.

Hypothyroidism is another condition that can make people feel cold. It affects the thyroid gland in the neck, causing it to not produce enough hormones to maintain energy levels and body temperature. This condition can be treated with synthetic hormones.

04
Vascular problems: Arteriosclerosis. | Image source: apollosugar.com

Blood maintains the circulation of limb tissues by providing nutrients and generating heat, so some blood vessel-related problems may also cause the human body to often feel cold. Arteriosclerosis is one such example.

Atherosclerosis is the narrowing of blood vessels due to a buildup of fatty plaques. There are different types of this condition, but the one that most often causes a cold sensation is peripheral arterial disease, which refers to a condition in which the arteries that supply blood to the body's extremities become narrowed.

If such diseases related to blood vessels and blood flow are not treated, it is possible to develop local anemia in the limbs, resulting in complete blood cut-off and gangrene, which may result in amputation to treat the condition and even death in the worst case.

Frostbite, Image source: Wikipedia

Chilblains are a familiar condition that can cause people to be sensitive to cold for a long time, even after the visible wounds have healed. Chilblains occur when the body (especially exposed skin) is subjected to below-freezing temperatures. The body reduces blood flow to the affected skin areas in order to prevent heat loss and maintain the temperature of vital organs. The ice crystals that form in the body are harmful to the body. They can tear into body tissues. In the worst cases, we can lose fingers and limbs.

As the cold months approach, keeping warm is very important for each of us. So, if you happen to be a person who is afraid of cold, you must wear clothes that can resist the cold, and take a hot water bottle and wrap yourself tightly with a small blanket. Remember, if you feel cold for any long time, you must go to the hospital for further diagnosis.

References:

https://theconversation.com/four-reasons-you-might-always-feel-cold-150016

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6456186/

https://www.ncbi.nlm.nih.gov/books/NBK546686/

Author:Taylor

Source: Principle