Why is it colder to lie down than to stand in winter and hotter to lie down than to stand in summer?

People's normal body temperature is generally around 37℃, with little change in 24 hours a day, generally lower in the morning and slightly higher in the afternoon.

The heat of human body comes from the oxidation of nutrients. If you eat something in cold weather, your body will feel warmer. This is the heat generated by food oxidation. After strenuous exercise, people will feel hot all over. This is because the muscle contraction movement is strengthened.

Muscle activity is strengthened, metabolism is fast, blood circulation is accelerated, and more heat is generated; If muscle activity is weakened, metabolism is slow, blood circulation is slow, and less heat is generated. If you want to keep warm in cold weather, you should strengthen exercise to increase the production of heat.

The reason why people can't fall when standing is because Zhang Liwei, whose muscles contract, holds the posture of people. When you lie down, you don't need to keep your posture, so your muscles are relaxed.

Muscle tension comes from muscle contraction, which generates heat. Because people are relaxed when lying down, they are in a state of tension and contraction when standing. Then, lying down is definitely colder than standing.

At the same time, when people lie down, muscles relax, skin pores open, and cold air can easily invade the body, causing colds. Therefore, people always cover themselves with quilts or blankets when they lie down.