Our skin endures much harsher conditions during the summer than we might realize.

Strong ultraviolet rays, sweat, and heat.
And once you go inside, it's air-conditioned.

Going from the hot outdoors to an air-conditioned room. And vice versa.

This back-and-forth actually puts a great strain on your skin.

The stress on the skin caused by sudden temperature changes is called "thermal shock."

Even just **going back and forth** between an air-conditioned room and the hot outdoors **can cause significant changes in skin temperature, blood flow, and moisture levels.**

Moreover, in the middle of summer, this happens multiple times a day.

So, what happens to skin that has been subjected to thermal shock?

① "Excessive dryness" where dried sweat strips away moisture.

After sweating profusely outside, I went into a dry, air-conditioned room.

When sweat dries quickly and is then exposed to even drier air, the skin becomes more prone to losing moisture.

We tend to think that our skin is moisturized because we're sweating, but actually, the opposite is true.

Your skin tends to get drier in the summer than you might imagine.

② Sudden temperature changes of 5°C or more can severely damage the skin's barrier.

In the scorching heat outdoors and in an air-conditioned room,Temperature difference of 5°C or moreThis is not uncommon.

If these rapid temperature changes are repeated many times, skin temperature and moisture levels will also change significantly each time.

Naturally, this puts a strain on the skin's barrier function that protects its moisture.

"My skin is sensitive even though it's summer."
"It dries out suddenly."
"My usual cosmetics sting."

Such changes can sometimes be related to the alternating cycles of heat and air conditioning.

③ Blood vessels are also extremely busy due to the heat and air conditioning.

In hot places, the blood vessels in the skin dilate to release body heat.

However, when you enter an air-conditioned place, your blood vessels constrict.

This process repeats many times a day, which is what happens to your skin in the middle of summer.

Each time your skin is subjected to sudden temperature changes and dryness, it becomes irritated.Even minor inflammation can easily occur.

UV rays aren't the only cause of blemishes and dullness.

And this is something that's surprisingly little known.
"As long as you apply sunscreen, you'll be fine in terms of preventing sunspots."

I think there are many people who feel that way.

But actually, that's not all.

If skin inflammation persists due to dryness or irritation, this can also lead to hyperpigmentation.

Furthermore, it is not ultraviolet light.Skin pigmentation can occur even with visible light.We know that.

In other words, even if you protect your skin from UV rays, neglecting skin inflammation and dryness can lead to dullness and dark spots.

Therefore, for summer skin,

Protect yourself from ultraviolet rays.
Do not let it dry out.
The goal is to prevent inflammation from lingering.

These three things are very important.

Since it happens every day, you might not even notice it at the time, but once it starts to cool down a bit,

"It feels kind of dry."
"It looks dull."
"stiff"
"I feel like I've suddenly aged."

Autumn is when those kinds of changes become clearly visible.

But it's okay.

There's a big difference between understanding that and not understanding it.It will make a world of difference to your skin in 5 or 10 years!

Next time, I'll talk about the skincare routines I recommend for this time of year, one by one.