It’s winter and respiratory illnesses are everywhere. Will going out underdressed in cold weather make me sick? | Donna Lu

IIt was inevitable that I would become, like Oscar Wilde, would become like my mother. After decades to have been invited to “put more clothes!” You will catch a cold! ” Now, despite the better, insist the same thing for my daughter.

“Another layer!” I ask my partner, who reluctantly brings together a toddler already as inflated as the Michelin man. The scientifically literate part of my brain understands that no jacket will protect it from the assault of daycare viruses. And yet, I cling to the conviction that underlining or going out with wet hair in winter must be avoided at all costs.

Are the cries to catch the death of his old wives transmitted as family inheritances, or is there a hint of truth in warnings?

The story or the touch of truth of the old women?

“People have more colds when the weather is cold,” said Hassan Vally, an associate professor of epidemiology at Deakin University. “It is a very natural thing for humans to search for models,” he adds, but stresses that correlation is not causation.

“You are not going to catch a cold while simply coming out in the cold,” said Dr. Larisa Labzin of the Institute of Molecular Bioscience at the University of Queensland.

To develop cold symptoms, you must be infected with a virus, whether it be one of the rhinoviruses, coronaviruses, adenoviruses, syncytial respiratory virus or any other of the 200 strains that cause colds. Although the flu can have similar symptoms, influenza viruses can cause much more serious illness.

Labzin says time has a substantial impact on the spread of these viruses. “The humidity really drops a lot in winter – it becomes really dry, your skin becomes really dry – and it really helps viruses.”

The humidity in the air hinders the suspension transmission in the air of the viruses, which means that if there is “there is a low humidity and that someone around you has the flu, it will better transmit to an additional distance,” says Labzin.

Respiratory diseases culminate in winter in temperate regions, but emphasize Vally that the tropics – where temperatures vary less all year – do not feel the same seasonal peaks. The rainy season in many tropical areas has been linked to a greater activity of the flu and RSV – which may seem counter -intuitive because the ambient humidity is then higher.

A hypothesis which can explain both winter epidemics in temperate regions and epidemics of the rainy season in the tropics is behavior: people spend more time inside to avoid cold and wet.

“Clear temperatures certainly encourage people to come together inside, which increases transmission,” said Professor Nathan Bartlett from Newcastle University. A cold day keeps us inside for about one to two hours more on average, and rainy weather 30 minutes more, according to an estimate.

Colder temperatures and immunities

Although being cold will not necessarily cause the capture of a cold, there is evidence that colder temperatures affect immunity, says Vally.

“Not only are there more opportunities to take a virus, but our immune response is also a little diminished,” admits Labzin.

“The fresh air, the dryer makes it possible to transmit viruses more effectively and removes innate immune defenses in the nasal passages – this is where these viruses enter,” explains Bartlett.

In dry winter weather, the mucus that lines our respiratory tract – which plays an important role in trapping harmful inhaled substances – becomes thicker, which makes it more difficult for hair cells in the airways to eliminate trapped particles and pathogenic agents.

Less exposure to the sun – necessary for our skin to produce vitamin D – in the coldest months can also have an impact on immunity. “There is evidence that vitamin D deficiency is a risk factor for increased respiratory infection during the winter,” explains Bartlett. Although a systematic review – the strongest form of scientific evidence – has found that vitamin D supplements can help protect against respiratory infections, other results suggest that supplementation is “unlikely to have a clinically relevant effect” in Australia, since a serious deficiency is not common here.

Exposure to cold can also be a factor of physical stress. “Whenever your body is subject to stress, you can get a transitional deletion of your immune responses,” explains Vally. “If you are in -20c without a coat, your body will be extremely stressed, just as it would be extremely stressed if it ran a marathon.”

Paradoxically, some small studies have shown that the stress of repeated exposure to cold water slightly active the immune system, suggesting that the bodies of the usual winter swimmers develop adaptive changes.

In the end, the capture of a cold results from a “complex interaction between the virus, the host and the environment”, explains Bartlett. “The three are in a constant state of flow – and winter coincides with changes in all these factors.”

How to avoid winter lurgies

“For the flu, for Covid, there are obviously available vaccines,” says Labzin, noting that a JAB RSV is now recommended for immunocompromised groups. “The best protection … is to be vaccinated.”

Fluing vaccination rates in Australia in all age groups are considerably decreasing compared to figures for 2020.

“It is important that people do not take antibiotics for a viral infection, because antibiotics will do nothing,” explains Labzin, citing the growing problem of antimicrobial resistance.

Minimize the transmission by practicing good hygiene, by carrying a breathable mask and staying at home while sick is familiar to most of the cocovid pandemic – and the same advice applies to colds.

Donna Lu is Deputy Editor -in -Chief of Guardian Australia

Antiviral is a bimonthly chronicle which questions the evidence behind major health titles and de facto verifications of the demands of popular well-being