Hello, whether to open the window in summer is related to the space in your room. If the room space is large enough and the indoor air is sufficient, it is best not to open the window at night to avoid catching a cold. However, the room space is very small, and it is easy to lack oxygen for a long time, which seriously affects sleep. This kind of room needs to be opened at night to avoid dizziness the next day. From the health point of view, it is good to sleep with the window open at night. If the house is not ventilated, the indoor oxygen is limited. If you inhale a small amount of oxygen and a large amount of carbon dioxide, you will have a slight headache the next day, feeling like you haven't woken up and your head is heavy. So look at the windows more and keep it ventilated. From the traditional health knowledge, it is good to close the window and sleep at night. However, although opening a window can ventilate, substances that cause people's allergies and noises that affect sleep will also enter the bedroom through the open window, which will seriously affect the quality of sleep. If you lie by the window and don't use curtains to keep out the wind properly, the wind will blow directly on you, and you may catch a cold. It would be even worse if mosquitoes or something flew in. According to the traditional health knowledge in China, it is best to close the window when sleeping at night. Because, in the traditional health theory, when people sleep quietly, they will produce an energy protective layer similar to the external atmosphere. The wind will take away your external energy, which may cause unstable sleep or feel tired after waking up. So close the doors and windows to sleep when you rest at night. You can open the window for ventilation before getting up in the morning and going to bed at night. If you really want to open the window, that's fine, but be careful to stay away from it. Don't point your head or feet at the window. It's best to install curtains on the windows to prevent wind and mosquitoes.