Moving frequently between outdoor heat like Mumbai’s 40°C temperatures and a cool, air-conditioned environment at around 20°C can disrupt your respiratory system. The delicate lining of your nose and airways
is designed to adapt to gradual temperature changes, not sudden shifts.
When the body cools down too quickly, the blood vessels in the nose constrict and then dilate rapidly, which can trigger vasomotor rhinitis. This leads to swelling, excess mucus production, and cold-like symptoms such as a runny or blocked nose, even in the absence of an infection.
Repeated exposure to such temperature fluctuations can also stress the tiny hair-like structures called cilia, which help clear dust and germs from the respiratory tract. Over time, this can cause inflammation that mimics a cold, leaving you feeling unwell even when test results are negative.
Dr. Divya Gopal, Additional Director of Internal Medicine, Sir H.N. Reliance Foundation Hospital, shares more:
Humidity and Dry Air
Air conditioners effectively cool the air but also remove moisture. Ideally, indoor humidity should be maintained between 40% and 60%. However, prolonged use of air conditioning can reduce humidity levels to as low as 20–30%.
Dry air can dehydrate the mucosal lining of the nose, weakening its ability to trap viruses and pollutants. When this natural defence is compromised, viruses can multiply more easily, leading to what many people describe as a “summer cold.” People often notice their symptoms improve when they step outside into more humid air.
Taking Care of Your Air Conditioner Matters
Not all “summer cold” symptoms are caused by temperature changes alone. Poorly maintained air conditioner filters can accumulate dust, pollen, mould and bacteria, which may then circulate in the air you breathe.
These particles can trigger inflammation similar to allergic reactions, causing persistent sneezing, fatigue and nasal irritation. Regular servicing of your air conditioner is essential, without it, a cooling system can become a source of respiratory discomfort.
What Is a Safe Temperature Difference?
Doctors recommend keeping the difference between indoor and outdoor temperatures within 8–10°C. If it is 40°C outside, set your air conditioner initially to around 28–30°C. Gradually lower it to 24–26°C, allowing your body to adjust comfortably without placing stress on your respiratory system.
Air conditioning is essential in extreme heat, but excessive cooling, dry air and poor maintenance can contribute to cold-like symptoms. By maintaining moderate temperatures, servicing your air conditioner regularly, and allowing your body time to adapt, you can reduce the risk of developing a “summer cold.”
If symptoms persist for more than a week or are accompanied by fever or body aches, it is important to consult a doctor.
