Why Do Colds and Flus Seem More Frequent During Winter?
As the weather turns cold, we tend to spend more time indoors with others in less well-ventilated spaces. This can lead to viruses spreading more easily. However, there are also distinctive biological mechanisms at play during winter that might explain why you catch a cold or flu more often during this season.
The Role of Temperature and Humidity
Our body’s first line of defense against viruses we might inhale is the epithelial tissue lining our nasal passages. Usually, when a viral infection is detected, these cells ramp up production of tiny liquid-filled sacs called extracellular vesicles. These help clean the nose of viral particles trying to invade our body, according to Dr. Benjamin Bleier, an expert at the Massachusetts Eye and Ear Center.
These vesicles contain molecules called microRNA, which prevent viruses from reproducing and penetrating further into our tissues. Disruptions to this system might explain why you catch more colds during winter.
Winter’s Impact on Your Immunity
Dr. Bleier and his colleagues have found that our immune system is indeed affected during winter. With a different defensive response, we may catch more colds. Here’s how it works:
Extracellular vesicles cannot divide like cells but are mini-copies created specifically to kill viruses. They act like "traps", catching viruses when we inhale them instead of allowing them to attach to cells.
In a study, participants were exposed to a temperature of 4.4°C (39.9°F) for 15 minutes, and their nasal conditions were measured afterward. This explained why we catch more colds during winter. The study found that being exposed to cold air can cause nasal temperature to drop by up to 9°F (5°C), eliminating the immune benefits from our noses. As a result, the production of extracellular vesicles decreases by 42%, making our body less able to fight off viral infections.
So, the next time you feel a cold coming on during winter, remember that it’s not just about spending more time indoors with others – it’s also about the impact of the cold on your body’s defenses. Stay warm, and consider these tips to boost your immunity during winter.
