Blood pressure (BP) is the abbreviation of systemic arterial blood pressure, which refers to the pressure acting on the blood vessel wall when blood flows in blood vessels, and is also the driving force to promote blood flow in blood vessels. When the temperature rises, the blood vessels will relax after self-regulation, and at the same time, they will secrete more sweat and lower their blood pressure; When high temperature leads to emotional impatience, the heart rate will increase and blood pressure will rise. Because it is hot in summer, some people like to turn on the air conditioner very low, especially when they go home from outside, hoping to cool themselves down as soon as possible. When it is cold and hot, the blood vessels will suddenly change from the original relaxed state to the contracted state, which lays a hidden danger for blood pressure fluctuation. Staying in an air-conditioned room for a long time is a heat wave as soon as you go out, and your blood vessels dilate again, so your blood pressure will fluctuate all the time. It is suggested that the indoor temperature should not be too low, 27℃, not lower than 25℃, and the temperature difference between indoor and outdoor should not exceed 8℃. Try to avoid staying in an air-conditioned room for a long time. It is best to turn on the air conditioner 1~3 hours and turn it off for a while, and open the window to breathe fresh air. If conditions do not permit, it is best to go to outdoor corridors and other places with windows for air exchange every 1 hour; Even if it is hot, don't stand under the air conditioner and blow directly. It is best to blow the wind upward to avoid the cold wind blowing directly on the back, shoulders, neck and head. Especially when the head is blown by cold air for a long time, it is easy to cause poor blood gas operation and insufficient blood supply to the heart, which is dangerous.