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The term “man flu” takes a humorous poke at men with minor respiratory infections, such as colds, who supposedly exaggerate their symptoms.

According to the stereotype, a man lies on the sofa with a box of tissues. Meanwhile his female partner, also with a snotty nose, carries on working from home, doing the chores and looking after him.

But is man flu real? Is there a valid biological reason behind men’s symptoms or are men just malingering? And how does man flu differ from flu?

What are the similarities?

Man flu could refer to a number of respiratory infections – a cold, flu, even a mild case of COVID. So it’s difficult to compare man flu with flu.

But for simplicity, let’s say man flu is actually a cold. If that’s the case, man flu and flu have some similar features.

Both are caused by viruses (but different ones). Both are improved with rest, fluids, and if needed painkillers, throat lozenges or decongestants to manage symptoms.

Both can share similar symptoms. Typically, more severe symptoms such as fever, body aches, violent shivering and headaches are more common in flu (but sometimes occur in colds). Meanwhile sore throats, runny noses, congestion and sneezing are more common in colds. A cough is common in both.

What are the differences?

Flu is a more serious and sometimes fatal respiratory infection caused by the influenza virus. Colds are caused by various viruses such as rhinoviruses, adenoviruses, and common cold coronaviruses, and are rarely serious.
Colds tend to start gradually while flu tends to start abruptly.

Flu can be detected with laboratory or at-home tests. Man flu is not an official diagnosis.

Severe flu symptoms may be prevented with a vaccine, while cold symptoms cannot.

Serious flu infections may also be prevented or treated with antiviral drugs such as Tamiflu. There are no antivirals for colds.

OK, but is man flu real?

Again, let’s assume man flu is a cold. Do men really have worse colds than women? The picture is complicated.

One study, with the title “Man flu is not a thing”, did in fact show there were differences in men’s and women’s symptoms.

This study looked at symptoms of acute rhinosinusitis. That’s inflammation of the nasal passages and sinuses, which would explain a runny or stuffy nose, a sinus headache or face pain.

When researchers assessed participants at the start of the study, men and women had similar symptoms. But by days five and eight of the study, women had fewer or less-severe symptoms. In other words, women had recovered faster.

But when participants rated their own symptoms, we saw a somewhat different picture. Women rated their symptoms worse than how the researchers rated them at the start, but said they recovered more quickly.

All this suggests men were not exaggerating their symptoms and did indeed recover more slowly. It also suggests women feel their symptoms more strongly at the start.

Why is this happening?

It’s not straightforward to tease out what’s going on biologically.

There are differences in immune responses between men and women that provide a plausible reason for worse symptoms in men.

For instance, women generally produce antibodies more efficiently, so they respond more effectively to vaccination. Other aspects of women’s immune system also appear to work more strongly.

So why do women tend to have stronger immune responses overall? That’s probably partly because women have two X chromosomes while men have one. X chromosomes carry important immune function genes. This gives women the benefit of immune-related genes from two different chromosomes.

Oestrogen (the female sex hormone) also seems to strengthen the immune response, and as levels vary throughout the lifespan, so does the strength of women’s immune systems.

Men are certainly more likely to die from some infectious diseases, such as COVID. But the picture is less clear with other infections such as the flu, where the incidence and mortality between men and women varies widely between countries and particular flu subtypes and outbreaks.

Infection rates and outcomes in men and women can also depend on the way a virus is transmitted, the person’s age, and social and behavioural factors.

For instance, women seem to be more likely to practice protective behaviours such as washing their hands, wearing masks or avoiding crowded indoor spaces. Women are also more likely to seek medical care when ill.

So men aren’t faking it?

Some evidence suggests men are not over-reporting symptoms, and may take longer to clear an infection. So they may experience man flu more harshly than women with a cold.

So cut the men in your life some slack. If they are sick, gender stereotyping is unhelpful, and may discourage men from seeking medical advice.

Thea van de Mortel, Professor, Nursing, School of Nursing and Midwifery, Griffith University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Sun exposure can accelerate ageing, cause skin burns, erythema (a skin reaction), skin cancer, melasmas (or sun spots) and other forms of hyperpigmentation – all triggered by solar ultraviolet radiation.

Approximately 80% of skin cancer cases in people engaged in outdoor activities are preventable by decreasing sun exposure. This can be done in lots of ways including wearing protective clothing or sunscreens.

But not all sunscreens work in the same way. You might have heard of “physical” and “chemical” sunscreens. What’s the difference and which one is right for you?

How sunscreens are classified

Sunscreens are grouped by their use of active inorganic and organic ultraviolet (UV) filters. Chemical sunscreens use organic filters such as cinnamates (chemically related to cinnamon oil) and benzophenones. Physical sunscreens (sometimes called mineral sunscreens) use inorganic filters such as titanium and zinc oxide.

These filters prevent the effects of UV radiation on the skin.

Organic UV filters are known as chemical filters because the molecules in them change to stop UV radiation reaching the skin. Inorganic UV filters are known as physical filters, because they work through physical means, such as blocking, scattering and reflection of UV radiation to prevent skin damage.

Nano versus micro

The effectiveness of the filters in physical sunscreen depends on factors including the size of the particle, how it’s mixed into the cream or lotion, the amount used and the refraction index (the speed light travels through a substance) of each filter.

When the particle size in physical sunscreens is large, it causes the light to be scattered and reflected more. That means physical sunscreens can be more obvious on the skin, which can reduce their cosmetic appeal.

Nanoparticulate forms of physical sunscreens (with tiny particles smaller than 100 nanometers) can improve the cosmetic appearance of creams on the skin and UV protection, because the particles in this size range absorb more radiation than they reflect. These are sometimes labelled as “invisible” zinc or mineral formulations and are considered safe.

So how do chemical sunscreens work?

Chemical UV filters work by absorbing high-energy UV rays. This leads to the filter molecules interacting with sunlight and changing chemically.

When molecules return to their ground (or lower energy) state, they release energy as heat, distributed all over the skin. This may lead to uncomfortable reactions for people with skin sensitivity.

Generally, UV filters are meant to stay on the epidermis (the first skin layer) surface to protect it from UV radiation. When they enter into the dermis (the connective tissue layer) and bloodstream, this can lead to skin sensitivity and increase the risk of toxicity. The safety profile of chemical UV filters may depend on whether their small molecular size allows them to penetrate the skin.

Chemical sunscreens, compared to physical ones, cause more adverse reactions in the skin because of chemical changes in their molecules. In addition, some chemical filters, such as dibenzoylmethane tend to break down after UV exposure. These degraded products can no longer protect the skin against UV and, if they penetrate the skin, can cause cell damage.

Due to their stability – that is, how well they retain product integrity and effectiveness when exposed to sunlight – physical sunscreens may be more suitable for children and people with skin allergies.

Although sunscreen filter ingredients can rarely cause true allergic dermatitis, patients with photodermatoses (where the skin reacts to light) and eczema have higher risk and should take care and seek advice.

What to look for

The best way to check if you’ll have a reaction to a physical or chemical sunscreen is to patch test it on a small area of skin.

And the best sunscreen to choose is one that provides broad-spectrum protection, is water and sweat-resistant, has a high sun protection factor (SPF), is easy to apply and has a low allergy risk.

Health authorities recommend sunscreen to prevent sun damage and cancer. Chemical sunscreens have the potential to penetrate the skin and may cause irritation for some people. Physical sunscreens are considered safe and effective and nanoparticulate formulations can increase their appeal and ease of use.

Yousuf Mohammed, Dermatology researcher, The University of Queensland and Khanh Phan, Postdoctoral research associate, Frazer Institute, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.