Cold tolerance of humans

Why are people more cold than others?

Cold weather, some people still wear thin clothes while you wear a lot of clothes and still feel cold. In fact, there are many people who always feel colder than others. So what is the cause? Can people reach the limit?

Pearl miners in Japan can soak themselves for hours in cold water without diving suits, while many people groan as soon as the sea water is fairly warm just in the Pacific or Indian Ocean.

(Photo: Reuters)

The perception of cold begins to form when the nerves in the skin send nerve impulses to the temperature of the skin to the brain . These nerve impulses not only react to the skin's temperature but also react to the rate of skin temperature changes.

Therefore, we feel cold when jumping into cold water compared to when we have been in cold water for a certain period of time, when the skin temperature is low but stable.

The episodes of nerve impulses caused by a temperature drop in the skin constitute early warning of a decrease in the body's original temperature (the temperature of internal organs). If not tested, the original temperature drop may cause hypothermia leading to death.

For healthy people, the body's physiological system prevents hypothermia from occurring. Nerve impulses from the skin are deposited in the subarachnoid area, which controls body temperature inside the body, giving instructions to the nervous system to control hypothermia.

The nerve impulses are sent to the muscles causing the whole body to shudder to create metabolic heat. Blood vessels are responsible for transferring warm blood from internal organs to cold skin, tightening, preventing blood flow and heat from flowing to the internal organs.

The nerve impulses run to the cerebral cortex, the site of the analysis of information and the creation of information about cold sensations. These nerve impulses combined with running pulses to the border system, the area of ​​emotional level analysis, will generate information about the degree of coldness. Cold feeling makes us perform certain behaviors such as cringing, wearing more clothes or complaining.

The cold feeling is sometimes not the same as the actual cold level of the body. Jumping into a cold water tank makes you feel cold, but the body's original temperature may increase because the warm blood remains in the internal organs. Body temperature can be maintained at a safe level within an hour.

At the beginning of the cold many people feel cold, at which time the original temperature begins to rise. During a cold, neural circuits that control body temperature are set at higher temperatures, so the body responds like a cold mechanism until its body temperature is stable at the heat level. setting level.

Some people suffer from Raynaud's symptoms, the flow rate is too slow to cause cold fingers and toes.

When the mother is pregnant, each fetus acts as a small incinerator. If the mother feels too cold, this may be a symptom of lack of hormones that act on the thyroid gland, so they need hormone supplements.

In the same environment, a person may feel colder than others. Women say they often feel colder than men in the same environment. The reason may be that women's skin temperature is lower than that of men, resulting in thicker subcutaneous fat and estrogen hormones.

Cold feeling is hereditary in some people . A study of twins found that the genetic ability of cold hands and feet is very high, reflecting the genetic basis of cold sensation.

Some people feel cold simply because the people nearby seem to be cold. This phenomenon is called 'cold feeling infection' . In one study, healthy volunteers were shown videos where the actors were cold or hot. Volunteers feel colder when they watch videos of the actors being shy. The temperature in the volunteers' hands decreased because of the tightening of the blood vessels to the hands, although the ambient temperature was not cold.

In the current social development, people rarely leave their bodies cold because they always wear many layers of clothing and use the thermal devices to help effectively. However, this is contributing to an increase in obesity rate when the body does not perform metabolic activity. It is possible that people will be healthier if they spend more time curing cold.