As winter sets in across India, many people notice a frustrating pattern, just as one cold fades, another seems to begin. A runny nose, scratchy throat, mild fever, blocked sinuses, on repeat. While it may feel like “low immunity,” research suggests the real reasons are far more practical and often linked to daily habits that quietly increase infection risk during colder months. Winter creates the perfect storm for these viruses to spread and thrive. Low temperatures, dry air, crowded indoor spaces and lifestyle changes collectively weaken the body's natural defences. Add a few common mistakes to the mix, and repeated infections become almost inevitable. Below are common mistakes that may explain why colds keep returning every winter and how to fix them.
Common mistakes causing infections in winter
1. Ignoring indoor air quality
Winter air is dry, especially with heaters, blowers, or room heaters running for long hours. Dry air dries out the nasal passages, reducing the effectiveness of mucus that normally traps viruses. Studies show that low humidity impairs the respiratory tract's first line of defence, making it easier for viruses to invade and multiply.
2. Washing hands less frequently than needed
Cold viruses spread mainly through hands touching contaminated surfaces, door handles, phones, lift buttons, office desks. In winter, handwashing frequency often drops because cold water feels uncomfortable. Research consistently shows that frequent handwashing significantly reduces respiratory infections, especially in shared environments like offices, public transport, and schools.
3. Underestimating sleep deprivation
Winter disrupts sleep patterns due to shorter daylight hours, late-night screen exposure, and irregular routines. Even a few nights of poor sleep can reduce immune response. Multiple studies confirm that people sleeping less than 6–7 hours are far more likely to catch colds after viral exposure compared to well-rested individuals.
4. Over-relying on heaters without ventilation
Closed rooms with heaters create warm but stagnant air, ideal for virus survival and transmission. Poor ventilation increases viral load in indoor spaces, especially when someone is already sick. Public health research highlights that inadequate air circulation increases respiratory infection spread, particularly in winter.
5. Low vitamin D levels
Vitamin D deficiency is extremely common in India during winter due to reduced sun exposure. Vitamin D plays a key role in immune regulation and antimicrobial response. Clinical studies show that people with low vitamin D levels experience more frequent respiratory infections, including colds.
6. Reusing handkerchiefs and towels
Using the same cloth handkerchief, towel, or pillowcase for days allows viruses to survive and re-enter the body repeatedly. Studies show that cold viruses can survive on fabrics for several hours to days, depending on humidity and temperature.
7. Skipping seasonal fruits and vegetables
Winter diets often become carb-heavy while fresh fruits and vegetables decline. This reduces intake of vitamin C, zinc, flavonoids, and antioxidants. Nutritional studies link low micronutrient intake with increased susceptibility to upper respiratory tract infections.
8. Exercising too little or too much
Cold weather discourages movement, leading to sedentary habits. On the other extreme, excessive high-intensity workouts without recovery can suppress immunity. Research indicates that moderate, regular physical activity strengthens immune surveillance, while inactivity or overtraining increases infection risk.
9. Treating every cold with antibiotics
Antibiotics do not work against viruses, yet they are frequently used for common colds. This disrupts gut microbiota, which plays a crucial role in immune health. Medical studies show that unnecessary antibiotic use can weaken immune response over time and increase vulnerability to future infections.
10. Going out in cold without layering properly
While cold exposure alone does not cause colds, getting chilled can reduce local immune response in the nasal passages. Cold stress can reduce blood flow to the nose, lowering immune cell activity and making viral infection easier.
Repeated colds in winter are rarely a sign of “weak immunity” alone. They are usually the result of multiple small mistakes adding up. Addressing these factors consistently can dramatically reduce infection frequency.
Disclaimer: This content including advice provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your doctor for more information. NDTV does not claim responsibility for this information.
References
Low Humidity and Viral Transmission, National Institutes of Health (NIH), 2019
Hand Hygiene and Respiratory Infection Prevention, Centers for Disease Control and Prevention (CDC), 2020
Sleep Duration and Susceptibility to the Common Cold, NIH, 2015
Indoor Ventilation and Respiratory Virus Spread, World Health Organization (WHO), 2021
Vitamin D and Acute Respiratory Tract Infections, NCBI, 2017
Survival of Respiratory Viruses on Surfaces, NIH, 2020
Micronutrients and Immune Function, NCBI, 2018
Physical Activity and Immune Response, NCBI, 2019
Impact of Antibiotics on Gut Microbiota and Immunity, NCBI, 2016
Cold Exposure and Upper Respiratory Infections, NIH, 2014
