Post-workout skincare: your pores do not open (and what does happen)

After a workout you have that flush, and underneath it skin that has had slightly more to deal with than you think. The advice you read everywhere is that your pores are "open" and that you should close them again with cold water.

That is not right. Pores have no muscles and cannot open or close. Below: what does happen, and what follows from it.

What exercise does to your skin

Circulation

Your heart pumps harder and the blood vessels just under your skin widen to shed heat. That is the flush, and it is why your skin looks fuller straight afterwards. It fades again as you cool down.

Sweat

Sweating serves one purpose: temperature regulation. You do not sweat out toxins, because your liver and kidneys do that work. What is in it is water, salt, urea and ammonia, and those stay behind on your skin after the water evaporates, where they are drying and mildly irritating.

Heat and sebum

Sebaceous glands produce more at higher temperatures. The mixture of sebum, sweat and the bacteria already on your skin is what can eventually cause congestion, particularly where none of it can get away.

Friction and occlusion

This is the factor most often skipped and the one that does the most in practice. A helmet strap, a headband, a sports bra, a phone against your cheek: wherever something presses against your skin while you sweat, you trap heat and moisture against it. Breakouts along your jawline or on your forehead under a headband are usually friction, not the exercise.

Why "closing pores" does not exist

A pore is the opening of a hair follicle with a sebaceous gland. There is no muscle tissue around it that can narrow it. What does happen: cold water makes skin contract slightly, so the pore looks smaller for a while.

That does not make rinsing with cold water pointless. It feels good and it takes the heat out. It just does not replace cleansing.

What does matter, in three steps

1. Cleanse within a reasonable time. Not in a panic within five minutes, but do not leave dried sweat on for hours either. A mild cleanser is better here than a strongly degreasing one, because your skin is already warm and stimulated. Radical Refresh is built for this, with aloe vera, green tea and 0.5 per cent salicylic acid for the congestion inside the pore.
2. Restore the water. Sweating costs water and salt. Hydration Hero on still-damp skin, with ceramides and squalane that also hold it in.
3. Seal it, and during the day with SPF. If you train outdoors or go outside afterwards, Daily Defense belongs in it. Sweat washes sun protection away, so after an outdoor session you start again.

These three are put together as The Cooldown Cicle, but the order matters more than the products.

Before you train

• Heavy creams and makeup off. Anything that forms a layer traps sweat and heat against the skin.
• No acids or retinol just beforehand. Freshly exfoliated skin plus sweat and friction irritates quickly.
• SPF if you train outdoors. Morning cycling and running add up, including in winter.

Exercise and your skin over time

Movement is good for your skin, mainly through sleep, circulation and stress. Be careful with what you read about exercise reversing ageing: that nearly always traces back to a single conference presentation that was widely amplified and never firmly confirmed.

What you can reasonably expect is more modest and still worth having: better colour, better sleep, and skin that recovers better.

Frequently asked questions

Do I have to shower immediately after training?

Immediately is not necessary, but do not leave it for hours. If you cannot get to it, wipe your face with clean water and cleanse properly later.

Why do I get spots along my hairline?

Usually a combination of sweat, hair products and a headband or helmet. Wash your face afterwards, and pay attention to what is in your hair that runs down while you train.

Is a cleanser necessary, or is water enough?

Water removes salt and sweat, but not sebum, makeup or the remains of your SPF.

Can I use my retinol after training?

Yes, provided your skin is cleansed and cooled down and does not feel irritated. Better to wait until the heat has gone out of it.

Sources

• Baker LB, Physiology of sweat gland function, Temperature, 2019.