Why are some people warm in winter and cool in summer?

Because human beings are warm-blooded animals, their body temperature remains relatively stable regardless of the external environment temperature. In winter, the temperature is below zero, and the body stays warm; Even if the weather temperature is higher than 40 degrees in summer, the body will adjust to 37 degrees. There is a thermoregulation center under the brain of warm-blooded animals, from which nerves lead to the muscles in the blood vessel wall of the whole body, so that they can regulate their own temperature.

Extended data:

In general, people's body temperature changes with day and night, sex, age, muscle activity and mental factors.

Skin is like an elastic natural barrier, which separates the human body from the external environment. When the weather is cold, the skin will feel the invasion of cold air and get a layer of "goose bumps"; When it is hot, your skin will sweat again, and you will be the first to react. There are peripheral temperature receptors on the skin and internal organs, just like "cold and heat sensitive electronic components", which are particularly sensitive to cold and heat stimuli.

The sensitivity it receives can transform this change into a nerve shock and send it to the center. The center responds in time and takes corresponding measures to adjust the body temperature balance. When people enter a cold environment, they can't help shivering. In this way, skeletal muscle contraction and increased thermogenesis are one of the important reactions to prevent hypothermia.

At the same time, the blood vessels of the skin contract, the blood flow slows down, the skin temperature drops, and the sweat is also reduced, which reduces the heat dissipation of the body to the outside world and keeps the body temperature constant; On the contrary, in high temperature environment, skin blood vessels dilate, blood flow increases, skin temperature rises, sweating increases, and heat dissipation is accelerated.

Baidu Encyclopedia-Warm-blooded Animals (Biological Species)