Why do I feel dizzy and nauseous after being exposed to air conditioning for a long time?

　　Under normal circumstances, prolonged exposure to air conditioning may cause dizziness and nausea due to dry air, poor air circulation, sudden temperature changes, hypotension, colds, or other reasons. It is recommended to seek timely medical consultation to identify the specific cause and receive targeted treatment. A detailed explanation is as follows:

　　1. Dry air

　　Air conditioners reduce indoor humidity while operating, causing the air to become dry. This may lead to dryness of the mucous membranes in the eyes, nasal passages, and throat, causing discomfort such as dry mouth and sore throat, which may further result in dizziness and nausea. It is recommended to use a humidifier indoors to increase air humidity.

　　2. Poor air circulation

　　Rooms with air conditioning typically have tightly closed windows and doors, resulting in poor air circulation. Prolonged exposure to such an environment can elevate indoor carbon dioxide levels while decreasing oxygen content, potentially causing mild hypoxia that leads to dizziness, often accompanied by fatigue, difficulty concentrating, and drowsiness. It is advised to regularly open windows for ventilation to maintain fresh indoor air.

　　3. Sudden temperature changes

　　Suddenly entering a cold air-conditioned room from a hot environment, or staying in a room with excessively low air conditioning temperatures for an extended period, may disrupt the body's temperature regulation, causing symptoms such as dizziness and nausea. Chills, sweating, and palpitations may also occur. It is recommended to adjust the air conditioning temperature gradually to avoid abrupt changes in temperature and to wear appropriate clothing for warmth.

　　4. Hypotension

　　In an air-conditioned environment, blood vessels may constrict as the body attempts to maintain a constant body temperature, potentially leading to hypotension. When hypotension occurs, reduced blood supply to the brain may cause dizziness and nausea, often accompanied by weakness, blurred vision, and an increased heart rate upon standing. It is recommended to follow medical advice to use medications such as midodrine tablets, flunarizine hydrochloride capsules, and propranolol hydrochloride tablets for treatment.

　　5. Common cold

　　Enclosed air-conditioned environments promote the growth of bacteria, viruses, and other pathogens. These microorganisms can spread through the air, increasing the risk of colds, which may trigger inflammatory responses that affect cerebral blood supply and nerve function, leading to dizziness and nausea, possibly accompanied by coughing, phlegm production, fever, and other symptoms. It is recommended to follow medical guidance to use medications such as antiviral oral liquid, Lianhua Qingwen capsules, and Ganmaoling granules for treatment.

　　It is recommended to keep a light jacket or shawl handy in air-conditioned rooms to avoid catching a chill. Additionally, increasing physical exercise can help enhance physical fitness and improve adaptability to environmental changes.