The Grapevine

Why Cold Weather Makes Us Sick

The public is slowly gearing up to protect themselves from the cold weather since the winter season is coming and temperatures are about to dip lower. The cold weather makes people more susceptible to acquiring the many cold viruses because much time is spent insulated indoors in close contact with those who could be potentially sick. 

Also, human blood vessels in the chest tend to conserve body heat when taking in cold air. When this happens, white blood cells take longer to travel to the mucous membranes, causing a barrier and delay for the body to kill germs. 

In certain scenarios, the dry air in winter could further dry up and harden the mucous membranes, thus worsening the cold manifold. In other cases, the cold weather can reduce immunity, inhibiting the body from handling the infection effectively due to a variety of reasons. 

As per Medical News Today, one of the main factors that contribute to lowering a person’s immune response is the lack of vitamin D. This tends to happen without much sunlight available in winter. Vitamin D is said to help boost immune function, hence is very much needed. Research so far has been inconclusive when studying the cold and its impact on health. However, studies on mice have proven that airway cells are more likely to be impacted when exposed to lower temperatures.

On the contrary, the virus itself and not the surrounding temperatures play a role in contracting colds. Rhinoviruses are the primary virus behind common colds, and sometimes even sore throats and ear infections. Same is the case with influenza viruses, where only the risk of getting sick increases in cold weather, while the temperature does not cause the flu independently. It is the virus' ability to multiply and survive easily during this weather that can make people fall sick easily. 

Man outside in snow Cold weather increases susceptibility to various diseases. Photo courtesy of Creative Photo Corner, Public Domain

Research indicates that rhinoviruses replicate faster in temperatures much lower than the average human body’s temperature, which is below 37 degrees Celsius or 98.6 Fahrenheit. For example, a drop to 33 degrees Celsius could enable the viruses to proliferate in the nasal cavity faster than normal.  

A study looked into how temperature variations affect the body’s immune response and found that when temperature and humidity was low consistently for three days, rhinoviruses entered the body more freely. Influenza viruses react the same way in cold weather. 

Other than infections, the cold weather also causes other health conditions. According to Healthline, they are as follows:

  • Bone Health - The health of our bones might suffer since there is less sunlight to absorb vitamin D and there is not enough opportunity to exercise outside. 
  • Heart Problems - Cold weather increases the risk of heart attacks because the blood vessels become constricted while pumping excess blood to maintain normal body temperature. In the heat, the heart works harder to pump blood into the organs. Due to this reason, blood clots form more easily and the potential of heart attack and stroke increases. 
  • Frostbite - Not only in extreme weather conditions but also in average cold weather, frostbite can cause blisters and the skin can become permanently blackened. It may also become difficult to move certain body parts when suffering from frostbite.
  • Hypothermia - Sudden shift in temperature can lead to hypothermia, a condition in which the body loses heat worryingly. In extreme cases, hypothermia can result in death. A fitting example is the scene from "Titanic," starring Leonardo DiCaprio’s character Jack. He froze to death in the ice-cold water made freezing by the iceberg formation that obstructed the iconic ship.