What is the principle of hot and cold?

There are four internal causes of cold.

1. The weather is hot, people sweat a lot, and sweat glands consume a lot of energy.

The days are long and the nights are short. The sultry weather affects people's sleep and rest, resulting in insufficient sleep.

3. In summer, many people have poor appetite, mainly light food, which affects the intake of protein.

Because of the hot weather, some people don't want to exercise, so they reduce their exercise time. Xia Han's external cause is excessive greed. If someone is sweating profusely, punch with cold water or take a cold bath; Some people like to enjoy the cool in the shade, in the passage or in the cold; Some people turn on the electric fan or turn down the temperature of the air conditioner when they sleep. Because the body surface or local environment suddenly turns from hot to cold, the blood temperature changes greatly, causing temporary reflex ischemia of nose and throat. At this time, people's resistance will be greatly reduced, so that the cold virus can March in. In fact, people who don't have enough rest, eat too much cold drinks and stay in closed air-conditioned rooms for a long time are most likely to catch a cold.