Working in the sun all day: can I protect skin from inside?

If you work outdoors in the sun all day, no way of protecting your skin from the sun from the inside has been confirmed. The sun advice for outdoor workers is all about the outside, covering and shading your skin: long sleeves, a wide-brimmed hat, sunglasses with UV protection, sunscreen of SPF 30 or higher reapplied at least every 2 hours, and shade during the strongest sun. Separately, drinking water regularly, eating proper meals and knowing the warning signs of heat are part of looking after your body on long, hot shifts, and a few changes in your skin are worth showing to a doctor.

Construction sites, farms, markets, delivery rounds on a motorbike, security posts, car parks and road work: in Thailand many people spend most of the working day under the sun. This article brings together advice from the US workplace health agency NIOSH (part of the CDC), the US Food and Drug Administration (FDA) and the UK's NHS on how to look after your skin and your body on those days.

Can I protect my skin from the sun from the inside?

This is one of the most common questions from people who work outside, because covering up and reapplying sunscreen in the heat is not easy.

The short answer

No way of protecting skin from the sun from the inside, whether a food, a drink or anything else you swallow, has been confirmed. All the advice from NIOSH, the FDA and the NHS on sun at work is about blocking and reducing the sun that reaches your skin: clothing, hats, sunglasses, sunscreen, shade and timing.

Where eating and drinking come in

The food and drink sections in this article are about looking after a body that works in the heat, not about protecting skin from the sun. Regular meals and enough water are part of looking after yourself on long, hot shifts.

What does a full day in the sun do to my skin?

People who work outdoors are in the sun for much of the working day, often every day of the year.

Sun reaches you more than you think

• NIOSH notes that you need protection even on cloudy days, because UV still gets through cloud.
• Light-coloured sand and other bright surfaces reflect UV, so it can reach your skin from below as well as from above.
• In summer, NIOSH says the period of highest risk is between 10:00 and 16:00.

In Thailand, the sun is high and strong for much of the year, so this window matters well beyond a single season.

What you may notice

The NHS says sunburn usually gets better on its own in 7 days or less, and advises getting out of the sun as soon as possible and cooling the skin.

Some medicines make skin more sensitive

NIOSH notes that some medicines can make skin more sensitive to the sun. If you take regular medicine and burn more easily than you used to, ask a pharmacist or doctor. Do not stop a prescribed medicine on your own.

How do I protect my skin while working outside all day?

Think in layers: what you wear, what you put on uncovered skin, and when and where you take your breaks.

Clothing, hat and sunglasses

• Clothing: NIOSH says dark clothing with a tight weave protects more than light-coloured, loosely woven clothing, and clothing with a high sun protection rating protects more still. Long sleeves and long trousers cover the most skin.
• Hat: a wide-brimmed hat shades the face, ears and neck. A cap leaves the ears and neck uncovered; a cloth flap at the back helps.
• Sunglasses: NIOSH recommends sunglasses with almost 100% UV protection and side panels.
• Gloves and neck covers: if you ride a motorbike or work with your hands in the sun, these cover areas that are easy to forget.

Sunscreen on what clothing does not cover

On a working day, reapplying every 2 hours is the part most people skip. It helps to tie it to fixed points in the day, such as the morning break, lunch and the afternoon break, and to keep a small bottle in your pocket, bag or motorbike seat.

Shade and timing

NIOSH advises employers to schedule outdoor work for times with less sun where possible and to provide shaded or indoor break areas. As a worker, you can:

• do the heaviest outdoor tasks earlier in the morning or later in the afternoon when you have a choice
• take breaks in the shade rather than next to the vehicle in the sun
• use umbrellas, awnings or a shade cloth over a fixed work spot, such as a market stall or a security post

For everyday skin care in hot, sunny weather, see How do you look after skin day to day in a hot climate?

How do I look after myself in the heat while working outside?

Sun on the skin and heat on the body come together. The NIOSH heat advice for workers is practical and easy to follow.

Drink before you feel thirsty

• For moderate work in the heat lasting under 2 hours, NIOSH advises 1 cup (about 240 ml) of water every 15 to 20 minutes, without waiting until you feel thirsty.
• Do not drink more than 6 cups an hour.
• Avoid alcohol and drinks high in caffeine or sugar while you work.

Keep a large bottle of water where you work and refill it at every break. Iced coffee and sweet tea are popular, but they do not count as your water.

Get used to the heat gradually

NIOSH advises building up time in the heat gradually over 7 to 14 days:

• New to working in the heat: no more than 20% of the usual time in the heat on day 1, then no more than 20% more on each following day. New workers should have lighter duties and longer, more frequent breaks.
• Worked in the heat before: no more than 50% of the usual time on day 1, 60% on day 2, 80% on day 3 and 100% on day 4.

Watch out for each other

NIOSH recommends a buddy system, where workers keep an eye on each other for warning signs. People in the early stages often do not notice them in themselves.

Warning signs of too much heat

What should I eat and drink on long days outside?

There is no special food for working in the sun. Regular meals and enough water are part of looking after yourself on long, hot shifts.

Regular meals from all the food groups

• Rice, noodles or bread at each meal, choosing brown rice or wholegrain when you can.
• Vegetables and fruit every day. A side of vegetables with your khao man gai or krapow, and fruit from the market cart such as watermelon, pineapple or guava, are easy ways to add them.
• Protein foods such as eggs, fish, chicken, pork, tofu and beans.
• Milk or soy milk as a drink between meals.

Do not skip meals on hot days

Heat can take away your appetite. If a full meal feels too much, eat smaller amounts more often. For more on skin in Thailand's hot and rainy seasons, see Dry, dull skin in summer, oily in rainy season: how to care?

Water through the day

Water is the main drink. Drink at every break, not only at lunch, and keep alcohol for after work, not during it.

When should I see a doctor about my skin?

Some redness after a long day is common. But the NHS advises getting medical help for sunburn if:

• your skin is blistered or swollen
• you have a very high temperature
• you feel very tired, dizzy or sick
• you have a headache or muscle cramps

If a baby or young child has sunburn, contact a doctor.

Changes in moles and marks

Because outdoor workers get so much sun, it is worth looking at your skin now and then, including the backs of the hands, the neck and the ears. The NHS advises seeing a doctor if:

• a mole has changed size, shape or colour
• a mole is painful or itchy
• a mole is inflamed, bleeding or crusty
• you have a new or unusual mark on your skin that has not gone away after a few weeks

Other reasons to see a doctor

• You burn much more easily than before, or since starting a new medicine
• You often feel dizzy, sick or faint at work even when you drink water and take breaks

Covering up, reapplying sunscreen and drinking water are things you do every day. Seeing a doctor when your skin changes is part of the same routine.