As the winter chill sets in and daylight becomes scarce, many find solace in the warmth of their homes. Yet, health specialists warn that too much time spent indoors could be weakening your immune system, increasing vulnerability to sickness.

Dr Emma Patel, alongside Ski Vertigo’s health and wellness experts, has highlighted a common health blunder made by Brits during the colder months: remaining inside all day. Despite the dreary weather, it’s vital to ensure you’re getting enough outdoor exposure.

There are several ways in which staying indoors can damage your immune system.

Dr Patel explained: “When we stay indoors for extended periods, particularly in heated, poorly ventilated spaces, carbon dioxide levels rise while oxygen levels decrease. Studies suggest that high CO2 concentrations can impair cognitive function and reduce the efficiency of the immune system, making it harder for your body to fight off infections.”

Woman with a headache lying on sofa, hand to forehead, eyes closed, profile
Staying inside all winter is tempting – but it could do more harm than good (Image: Getty Images)

Moreover, being cooped up inside means missing out on essential vitamin D. The NHS advises adults to take vitamin D supplements throughout the winter due to reduced sun exposure, which can lead to deficiencies, reports Surrey Live.

Vitamin D is integral to immune health, and its scarcity has been associated with heightened risks of respiratory illnesses, including flu and COVID-19.

While it’s tempting to crank up the heating as the weather gets colder, doing so could actually be harmful to your health.

Dr Patel warns: “Central heating and lack of airflow can lead to a build-up of indoor pollutants, such as dust, mould spores, and volatile organic compounds (VOCs) from household products. According to Public Health England, long-term exposure to these pollutants can cause inflammation in the respiratory system, making you more susceptible to viruses and bacterial infections.”

Not only that, but heating can also dry out the air, leading to irritated nasal passages and airways.

This can reduce the body’s natural defences against viruses. So, while it’s important to stay warm, it’s equally crucial to balance this with spending time outdoors to keep winter illnesses at bay.