As we lie on the precipice between summer and monsoon, the coughs and sneezes are increasing. Flu-like symptoms such as cough, cold, sore throat and fatigue are sweeping the streets of Kolkata as the temperature swings hot and cold. So, how does one prevent accompanying ailments and stay safe and infection free? Constantly moving between the hot outdoors and the cold air-conditioned indoor spaces are bound to mess up our systems.
What is the issue?
According to health experts, the core issue is thermal shock. That happens when our bodies struggle to cope with the dramatic switch from hot outdoor temperatures to chilled indoor environments. Diksh Goyal, senior consultant, Internal Medicine at Marengo Asia Hospital, said, “A sudden and extreme temperature change puts the body into stress. The body is forced to adjust from a hot environment to a cold one almost instantly, and that weakens the immune system’s response.”
This stress often compromises the natural thermoregulation process, making one more vulnerable to airborne viruses. Goyal further added, “It’s not just people with the flu — those with chronic sinusitis or allergic coughs are also experiencing worsening symptoms."
Weakened defences in dry air
Nasal passages, throat and even the eyes take a hit when moving into a cold dry environment from a hot and humid one Shutterstock
What happens when one moves into a cold dry environment from a hot and humid one is the nasal passages, throat and even the eyes take a hit. Arup Halder, consultant pulmonologist at CK Birla Hospital and CMRI Kolkata, said, “The sudden shift dries out the mucous membranes that usually act as a barrier against infections. At the same time, your immune system is already busy adjusting to temperature changes. This dual strain makes it easier for viruses to take hold.”
When you add poor indoor ventilation and unclean AC filters to the mix, it becomes a recipe for transmission. “Air-conditioned rooms with low humidity and poor airflow can concentrate pathogens like influenza and even strains of COVID,” warns Halder.
Vanishing thirst and masked hydration
The temperature change also affects the body’s normal cues like thirst. Goyal said, “When you're outside in the heat, you crave water. But as soon as you step into an air-conditioned room, that thirst disappears.” Because of the lack of thirst indoors, we are often left dehydrated, which further dries the respiratory tract, making it easier for viruses to invade.
Recognising the risk
Drink water regularly, even if you don’t feel thirsty. ‘Hydrated mucous membranes are your first line of defense,’ say doctors Shutterstock
Sauren Panja, senior consultant and administrative lead - Critical Care Services at Narayana Health, Kolkata, notes that symptoms often begin mildly — with sore throat, fatigue or low-grade fever. “People tend to self-medicate or turn to home remedies. But without proper assessment, symptoms can escalate and also spread to family members due to poor isolation practices.”
He advises early consultation with a physician to manage symptoms effectively and prevent complications.
Prevention is better than cure
To reduce the risk of falling ill this season, doctors recommend simple but effective lifestyle adjustments:
- Set your AC smartly: Keep air conditioners at an ambient 24°C–26°C. “Avoid setting the AC too low — it reduces the temperature gap and eases the load on your immune system,” says Panja.
- Dress in layers: Layering helps your body adjust gradually between indoor and outdoor temperatures.
- Stay hydrated: Drink water regularly, even if you don’t feel thirsty. “Hydrated mucous membranes are your first line of defense,” says Halder.
- Ventilate: Ensure good airflow in indoor spaces and clean AC filters at least once a month.
- Support your immunity: Get adequate sleep, eat balanced meals, and consider supplements like Vitamin D and zinc.
- Avoid midday exertion: Physical activity is best reserved for mornings and evenings to avoid exhaustion and heat-related symptoms.
- Use masks and sanitise: In crowded or closed public areas, wearing a mask and maintaining hand hygiene remains a smart precaution.
Temperature changes may not directly cause illness, but they weaken your body’s ability to fight off viruses. As Halder puts it, “Temperature swings compromise our natural defenses. Keeping mucous membranes hydrated and avoiding extreme AC settings are critical to breaking this cycle of susceptibility.”
So, this season, be mindful of your environment — and your body. Staying cool doesn’t have to come at the cost of your health.