Air conditioning, heating and tight skin: what the environment does to the face

After a day in an air-conditioned office, a night with the heating on or a long flight, many people feel their face tight, rough, at times itchy, and their make-up "cracking". It is not imagination: the air around us has a direct, measurable effect on the amount of water the skin can retain.

The good news is that, unlike many factors that affect the skin, the environment can be partly controlled, and the skin can be prepared for it.

What the studies say

Humidity and barrier

The most superficial layer of the skin, the stratum corneum, exchanges water with the air. When the air is dry, the skin loses water faster (transepidermal water loss increases) and the stratum corneum dries out. A review by Engebretsen and colleagues (2016) concluded that low humidity and low temperatures reduce the skin's barrier function and increase sensitivity to irritants and allergens. This helps explain why dermatitis and dry skin worsen in winter.

The skin adapts: after a few days in a dry environment, production of hydration factors increases. But sudden changes, such as going from damp cold into a warm, dry interior, are the hardest.

On the plane

In a study of eight women on long-haul flights (Guéhenneux et al., 2012), the relative humidity of the cabin fell below 10% about two hours after take-off and stayed there. Skin hydration fell on the face and forearms, especially on the cheeks, where it dropped by as much as 37%. The authors attribute the sensation of tight, itchy skin that many travellers report to this dryness.

Temperature

Cold reduces circulation in the skin and sebum production, and makes the barrier lipids less flexible. Excessive heat, on the other hand, increases perspiration and, when this evaporates in dry air, it accentuates dehydration. Very hot bath water also strips away lipids.

What is the ideal humidity?

For comfort and health, recommendations for indoor spaces put relative humidity, in general, between about 40% and 60%. With intense heating in winter, it often drops below 30%.

Environments that dry out the skin

Portugal has damp winters outdoors, but indoor spaces with electric heating or hot air can be very dry. And many offices have air conditioning all year round.

Who suffers most

• Dry and sensitive skin, which already has a more fragile barrier. See Sensitive skin and redness: everyday care.
• People with atopic dermatitis, seborrhoeic dermatitis, rosacea or psoriasis, which tend to worsen in winter and in dry environments. See Rosacea: what it is, causes and treatments.
• Older people, with less sebum and fewer lipids in the skin.
• Women after the menopause, because of the drop in oestrogen.
• People who use retinoids, acids or acne treatments, which increase water loss.
• People who spend many hours in front of a jet of air, as in the car or in offices with air conditioning.
• Cabin crew and frequent travellers.
• People who wash their face often or with very hot water.

What to do

In the environment

• Measure the humidity: an inexpensive hygrometer helps you know whether the air is the problem.
• Humidifier in the bedroom or office, if the humidity is below 40%. Keep it clean, with fresh water, to avoid fungi and bacteria, and do not exceed about 60%, so as not to encourage mould and dust mites.
• Moderate temperature: very high heating dries the air more. Around 19 to 21 °C is usually comfortable.
• Redirect the jet of air from air conditioning and the car away from your face.
• Air out the home daily; plants and drying laundry help little, but do no harm.

On the skin

• Gentle cleansing, with lukewarm water and a soap-free product, once or twice a day.
• Moisturiser with humectants and an occlusive: glycerin or hyaluronic acid to attract water, plus ceramides, dimethicone or petroleum jelly to retain it. In dry environments, a humectant alone is not enough. See Dry or dehydrated skin: what is the difference and why it matters.
• Apply to slightly damp skin, straight after cleansing.
• Reapply during the day in very dry environments; keep a lip balm and a hand cream nearby.
• Reduce irritating actives (acids, retinoids, exfoliants) during phases of greater dryness.
• Sunscreen even in winter.
• Short baths with lukewarm water.

On the plane

• Travelling without make-up or with light make-up.
• Apply a richer moisturiser before the flight and reapply midway.
• Lip balm.
• Drink water regularly and moderate alcohol and caffeine, for general comfort.
• Avoid spraying water on the face without applying a cream on top: evaporation may increase dryness.

When the discomfort is something else

A dry environment explains a lot of tight skin, but seek assessment if:

At Luxmed, the skin assessment helps to understand whether the dryness is mainly environmental, whether the barrier is altered or whether there is another condition, and to adjust the routine to your skin, your work and the season. When it makes sense, an in-clinic hydration protocol can help you recover faster in the driest phases.

This article is for information only and does not replace a medical consultation.

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