Suitable temperature and humidity for respiratory diseases

Temperature 18-24℃, relative humidity 40%-60%. This range is not a one-size-fits-all standard. Different conditions and different groups of people can be flexibly adjusted according to actual conditions.

Don't underestimate the difference of a few degrees Celsius or more than ten percentage points. I have encountered too many patients who have fallen into this situation in the respiratory clinic. Uncle Zhang, an old chronic bronchitis patient who lives in the Northeast, had to turn on the heating to 28°C in winter to avoid freezing. As a result, he kept waking up coughing in the middle of the night. His throat was as dry as if he had swallowed sandpaper. When he came for a follow-up examination, his lung function had dropped a bit compared to last month. ； There is also a little girl in high school who suffers from allergic rhinitis. During the rainy season, her home is stuffy and damp, with the humidity soaring to more than 80%. She has been sneezing and sneezing non-stop for a week, and she has asthma. She can't even catch up with the midterm exam.

Why is the temperature 18-24℃? To put it bluntly, it fits the tolerance of the respiratory mucosa itself: the respiratory mucosa is like a thin sponge wrapped in mucus. When the temperature is suitable, it is soft and can stick to the dust and viruses inhaled, and then move it to the throat through the cilia and cough it out. If the temperature is lower than 18°C, the cold air will cause the blood vessels in the mucous membrane to shrink directly and the ciliary swing speed will slow down. Viruses and bacteria can easily take root in the respiratory tract. ； If the temperature is higher than 24°C, the moisture in the air evaporates quickly, and the mucus layer on the surface of the mucous membrane dries quickly. The barrier function is directly reduced by half, and people tend to feel stuffy. Patients with COPD may even experience a drop in blood oxygen. Of course, not everyone is stuck with this number. Our clinical advice to patients in the acute exacerbation of COPD is often to ask them to increase the temperature by 1-2°C, especially when they first enter the house from outdoors, to avoid the sharp temperature difference irritating the respiratory tract. ； When pediatricians meet young children with syncytial virus infection, they usually recommend adjusting the temperature to 22-26°C. After all, children have poor body temperature regulation. They are prone to fever if they are too cold, and they are prone to dehydration if they are too hot.

Temperature must be considered in conjunction with humidity. Only when the two are combined can it really help reduce the burden on the respiratory tract. The Chinese Center for Disease Control and Prevention has previously conducted tracking data. When the humidity is lower than 40%, the survival rate of the influenza virus can be increased by more than three times. The amount of immunoglobulin A secreted by the mucous membrane is directly cut in half, which is equivalent to the respiratory protective shield being thinned by half. ； If the humidity is higher than 60%, the reproduction rate of mold and dust mites will directly double, and patients with allergic rhinitis and asthma can easily be induced to have acute attacks. There are also different clinical opinions here: For example, when encountering children with acute laryngitis and herpetic angina, we would recommend parents to raise the humidity to 60%-70% for a short period of time, which can quickly relieve the symptoms of sore throat, as long as they do not maintain this humidity for a long time. ； There are also patients with persistent cough after mycoplasma infection who have itchy throats and keep coughing. If the humidity is increased by 5%-10%, the comfort can be greatly improved. There are even studies that specifically mention that patients with particularly severe dust mite allergy can control the humidity at 35%-40% for a long time. After all, dust mites cannot survive in an environment with a humidity below 40%. On the contrary, it can reduce the probability of attacks. This is an adjustment that varies from person to person.

Let me tell you something interesting. There was an old patient who specially put a thermometer and hygrometer next to his pillow, saying that he should keep an eye on the value 24 hours a day. As a result, he was so nervous that he couldn't sleep well and coughed more violently. It was completely unnecessary. An ordinary thermometer and hygrometer costing more than ten yuan is enough. Stick it about 1.5 meters above the ground, not facing the air conditioner or next to the humidifier. The measured value is enough for reference. In the winter, if you turn on the heating and it gets dry, just use a humidifier instead of adding tap water. I have met several people who got Legionnaires' pneumonia by using tap water to humidify. Just use purified water or boiled water, change the water every day, and remove the scale every week, otherwise it will be like spraying bacteria into the air. During the rainy season, turn on a dehumidifier when the humidity is high. It is much easier to dehumidify than an air conditioner. The temperature will not drop sharply and the respiratory tract will not freeze easily. There used to be a young man suffering from allergic asthma. The humidity in his home used to be over 70% all year round, and he would get sick once a month. Later, he took advice and bought a small dehumidifier to control the humidity at about 50% all year round. He has not had an attack for half a year, and even reduced the amount of hormone inhalers by half.

To put it bluntly, these values ​​​​are just for everyone’s reference. The core is to make your respiratory tract feel comfortable while avoiding extreme situations that can easily cause problems. After all, nourishing the respiratory tract is similar to raising flowers and plants. It won't work if it's too dry, too waterlogged, too cold, or too hot. It's much more useful to feel how you feel than to pick out numerical values.