Why You Catch More Colds in Winter: The Secret Behind Seasonal Influenza (flu) – Symptoms and causes – Mayo Clinic”>Viruses
Winter brings with it a familiar cycle: the thermostat goes up, we huddle indoors, and cold and flu season takes hold. But why do we catch viruses more often during the colder months? It’s not just about being cooped up together; there are compelling biological reasons behind the seasonal spike in infections.
The Common Cold and Flu: More Than a Room Full of People
When the temperature drops, we tend to spend more time indoors, creating an ideal environment for viruses to spread through respiratory droplets. However, the increase in infections isn’t solely due to proximity. The viruses themselves, such as rhinoviruses and influenza, thrive in cooler temperatures and lower humidity, which are common in winter.
Why Your Nose is Your First Line of Defense
The nose isn’t just there to keep out unwanted particles; it’s also our first line of defense against viruses. The epithelial cells that line our nasal passages produce mucous that traps incoming particles, and when infected, these cells ramp up production of tiny sacs called extracellular vesicles. These structures not only help absorb viral particles, but also contain microRNAs that inhibit viral replication, preventing them from invading the rest of our body.
Cold Weather and the Nasal Response
According to Benjamin Bleier, MD, director of endoscopic skull base surgery at Massachusetts Eye and Ear, the nasal response to viral infections is weakened in cold weather. When we step out into the chilly air, the temperature inside our nose drops from its normal 98.6°F (37°C) to around 89.6°F (32°C). This temperature dip affects the nasal epithelial cells, lessening their ability to produce the crucial extracellular vesicles and microRNAs.
The Role of Humidity
Another factor at play is the decrease in humidity indoors during winter. As we heat our homes, the air becomes drier, reducing the effectiveness of our nasal cavity’s mucosal network. This makes it easier for viruses to bypass our first line of defense and attack.
Preventing Winter Viruses
While we can’t control the weather, we can take steps to protect ourselves:
- Boost your immunity through regular exercise, a balanced diet, and adequate sleep to better fight off infections.
- Practice good hygiene, covering your mouth when sneezing, washing your hands frequently, and cleaning surfaces regularly to decrease the spread of viruses.
- Stay hydrated to maintain mucosal integrity and aide in immune function.
- Consider a humidifier to maintain indoor humidity levels between 40-60%.
Understanding the biology behind our winter viral woes can help us take proactive measures and maybe — just maybe — give us a fighting chance against the inevitable office cold or holiday virus.
