From the Guidelines
Cold exposure does not directly cause catching a cold, as colds are caused by viruses, primarily rhinoviruses, not by being exposed to cold temperatures. When people say "catching a cold" after cold exposure, they're referring to developing symptoms of a viral respiratory infection, but the cold weather itself isn't the cause. According to the most recent and highest quality study, 1, routine vitamin C supplementation is not justified to reduce the incidence of colds in the general population, yet vitamin C may be useful for people exposed to brief periods of severe physical exercise.
Key Points to Consider
- Cold temperatures may indirectly increase your susceptibility to viral infections by causing physiological changes like decreased blood flow to mucous membranes and reduced immune function in the nasal passages 1.
- Cold weather often leads people to spend more time indoors in close proximity to others, increasing exposure to viruses 1.
- Cold air can also dry out nasal passages, reducing the effectiveness of mucus in trapping viruses 1.
- If you're concerned about preventing colds, focus on frequent handwashing, avoiding close contact with sick individuals, not touching your face, and maintaining good overall health through adequate sleep, hydration, and nutrition rather than simply avoiding cold temperatures 1.
- The use of nasal corticosteroids for symptomatic relief from the common cold is not supported by current evidence, and there is some low-quality evidence that probiotics may be beneficial in reducing the mean duration of an episode of acute URTI 1.
Recommendations for Prevention and Treatment
- Frequent handwashing is essential to prevent the spread of viruses 1.
- Avoiding close contact with sick individuals can help reduce the risk of catching a cold 1.
- Not touching your face can prevent the transmission of viruses from your hands to your eyes, nose, and mouth 1.
- Maintaining good overall health through adequate sleep, hydration, and nutrition is crucial to prevent colds 1.
- Vitamin C supplementation may be useful for people exposed to brief periods of severe physical exercise, but its effectiveness in preventing colds is still debated 1.
From the Research
Cold Exposure and Catching a Cold
- Cold exposure has been associated with an increased risk of developing upper and lower respiratory tract infections, as well as increased morbidity and mortality during winter months 2.
- The pathophysiological responses to cold exposure, such as vasoconstriction in the respiratory tract mucosa and suppression of immune responses, may contribute to increased susceptibility to infections 2.
- However, not all studies agree on the relationship between cold exposure and immune function, with some suggesting that cold exposure does not depress immune function 3.
Mechanisms of Cold Exposure and Infection
- Acute cooling of the body surface may cause reflex vasoconstriction in the nose and upper airways, which can inhibit respiratory defense and contribute to the onset of common cold symptoms 4.
- Cold exposure can lead to changes in physiological and immunological parameters, including increased levels of norepinephrine and cortisol, lymphocytosis, and decreased lymphoproliferative responses 5.
- Severe chilling can suppress several cellular and humoral components of the immune response, including lymphocyte proliferation and natural killer cell count 6.
Immune Responses to Cold Exposure
- Exposure to cold temperatures can impose stress on the human body, leading to circulatory and metabolic changes, and potentially depressing the immune system 5.
- Adaptation to cold exposure can develop over time, but further work is needed to examine interactions between cold exposure and exercise, and to determine whether disturbances of immune response are sufficient to impair immunosurveillance in human subjects 6.
- The relationship between cold exposure and immune function is complex, and more research is needed to fully understand the mechanisms involved 2, 3, 4, 5, 6.