Sunlight, fresh air & getting outside

Experts on light and health note that indoor lighting is usually set at least ten times lower than natural daylight. Your eyes adjust so well that you may not notice how dim it really is.

The NIH notes that light from electronic devices at night can confuse your body clock.

EPA studies found levels of about a dozen common pollutants to be 2 to 5 times higher inside homes than outside. Ventilation helps bring in fresher air.

Researchers at the University of Colorado Boulder sent volunteers camping with no electric light. After a summer week, people got about four times more daylight than usual, and their body’s “night-time” signal started nearly two hours earlier.

In a follow-up, just a summer weekend of camping shifted body clocks about 1.4 hours earlier. A winter week brought 13 times more daylight than a usual winter weekday.

In the first camping study, people with later body clocks showed the biggest shifts, ending up more like the early risers.

Experts recommend bright light during the day, dimmer light in the three hours before bed, and a sleeping space that is as dark as possible.

Because indoor light is so much dimmer than outdoor light, stepping outside on an overcast day still gives your eyes a much bigger light signal than staying in.

The experts recommend using daylight indoors where you can. Sitting close to a window is brighter than the middle of a room. Stepping outside is brighter still.

Easy upgrades

• Move your desk or favorite chair near a window
• Open blinds and curtains fully in the daytime
• Take calls or breaks outside
• Walk part of a trip you’d usually drive

The same experts recommend keeping light low in the three hours before bed, and keeping the bedroom as dark as possible while you sleep.

Ideas

• Switch to lamps instead of bright ceiling lights
• Turn screens down or off as bedtime gets closer
• Use blackout curtains or an eye mask

The researchers suggested that seeking bright light by day and avoiding light at night may be a simple, low-cost way to support mental health. It works best alongside other support, not instead of it.

For some people, low mood returns each autumn and winter. That pattern has a name and can be treated.

Your master clock tells the brain when to make you sleepy in the evening, based on how much light your eyes get.

In a Harvard study, 24 office workers spent workdays in a controlled office. On days with more outdoor air and fewer chemical fumes, their scores on thinking and decision tests were about twice as high as on “conventional office” days.

It was a small study in a test office, so real offices may differ. It still suggests stuffy air may affect more than comfort.

EPA suggestions

• Open windows and doors when the weather allows
• Run kitchen and bathroom fans
• Ventilate well when painting, sanding or cooking
• Remove or reduce sources of fumes when you can

Keep windows closed if outdoor air is smoky or polluted. The EPA advises thinking about nearby smoke or other outdoor pollution before ventilating.

Try it

1. Step outside, onto a balcony or by an open window.
2. Breathe in slowly through your nose, and out a little longer.
3. Look at the farthest thing you can see.
4. Notice the temperature and air on your skin.
5. Go back in and pick one small next step.

Ideas

• Drink your morning drink on a step or balcony
• Walk the kids to school, or walk to the bus stop the long way
• Do a few stretches by an open window
• Walk the dog before breakfast

Ideas

• Eat lunch outside, even for 10 minutes
• Take a walking phone call
• Sit by a window for a work task
• Do errands on foot

Between 10 a.m. and 4 p.m. UV rays are strongest in the continental U.S., so bring shade or sun protection if you’ll be out a while.

Ideas

• Get off one stop early and walk
• A short family walk before dinner
• Water plants or sit in a garden
• Watch the sunset

As bedtime gets closer, dimmer light helps your body get ready for sleep.

Ideas

• Step out to look at the moon or stars
• Switch to lamps after dinner
• Keep phones out of the bedroom

The CDC says to protect your skin all year when the UV index is 3 or higher, not just in summer.

CDC tips

• Seek shade
• Use broad-spectrum sunscreen with SPF 15 or higher
• Wear a wide-brimmed hat and sunglasses
• Wear clothes that cover your arms and legs

U.S. Air Quality Index (AQI)

• 0–50 Good (green)
• 51–100 Moderate (yellow)
• 101–150 Unhealthy for sensitive groups (orange)
• 151–200 Unhealthy (red)
• 201–300 Very unhealthy (purple)
• 301 and up Hazardous (maroon)

You can check the AQI for your area at AirNow.gov. On orange days and higher, consider shorter or gentler time outside, or bring the “outdoors” in with a window view or nature sounds.

In heat waves, aim for cooler morning or evening time outside, drink water, and take breaks in the shade.

In winter, the brightest part of the day may be the only light you get. A 10-minute walk at lunchtime in warm layers can be worth more than a long evening walk in the dark.

Ideas

• Sit or rest close to the brightest window
• Open a door or window for fresh air when the air is clean
• Ask someone to help you onto a porch or balcony for a few minutes
• Keep curtains open during the day

If you work nights, timing light and darkness around your shifts matters. Bright light at the wrong time can make daytime sleep harder.

Tiny steps

• Open the curtains
• Stand in the doorway for one minute
• Walk to the mailbox and back
• Sit on the step with a warm drink

Ideas

• Go in daylight on busier, well-lit routes
• Go with a friend, neighbor or group
• Tell someone where you’re going
• Try a library garden, courtyard or park near other people

Meeting outside instead of indoors adds daylight and fresh air to time you’re already spending together.

Ideas

• A short walk after dinner
• Weekend picnic, even on the front step
• Morning walk to school
• Outdoor games at the park

The CDC lists joining a community garden and volunteering as ways to connect. Outdoor groups like gardening, park clean-ups or walking groups add daylight too.