Not everyone can walk or cycle to work,
sit next to a large window or get outside
during their lunch break (see “Optimise
your exposure”, page 35). But even indoors,
we can improve our access to the right light.
A national standards body in the UK just
released guidelines calling for more daylight
in buildings, for instance, and “human-
centric” lighting systems are springing up in
care homes, hospitals, schools and workplaces.
The idea is that by adjusting the blueness – and
sometimes the brightness – to more closely
replicate conditions outdoors, we could
improve our sleep, health and well-being.
In the dementia wing of the Ceres Center,
a residential care home in Horsens, Denmark,
the lights are an intense white-blue during the
day, dimming to soft amber in the evening.
Bedrooms are kept dark at night, although
residents who get out of bed then will trigger
an amber bathroom light. Night-waking is
a frequent problem among people with
dementia. Not only does this put them at risk
of falling, it is also associated with delirium or
confusion. A related problem is sundowning,
where people with dementia become more
agitated, aggressive or confused in the early
evening. Both phenomena have been
associated with disturbed and flattened
circadian rhythms, and they seem to worsen
during the short, dark days of autumn and
winter, especially when it is cloudy.
A decade ago, a clinical trial in the
Netherlands suggested that tweaking the
lighting might help. Six care homes were
fitted with additional bright lights, raising the
indoor illuminance between 10 am and 6 pm
to the level you would expect outdoors on an
overcast day. In six other homes, the lightingAm I getting enough sunshine?
As evidence piles up about the
harms of spending so many
hours inside in a kind of
perpetual dusk, I have started
to wonder if I am being
exposed to all the light I need.
To find out, I downloaded
a phone app that measures
light intensity. When I first
fired it up, I could see out of
the window about 5 metres
from my desk in the New
Scientist office that it was an
overcast afternoon. Yet it felt
reasonably light and airy
where I was sat, and the
app told me I was bathed in
134 lux of light. That sounded
all right.
But as I began taking
readings at regular intervals —
at breakfast, during my
commute, at my desk, at
lunchtime and at home in the
evening — I realised just how
much time I was spending
inside in relatively dim
conditions. When I ate lunch
outside on a bench the next
day under a mixture of sun
and clouds, the lux reading
was 4111. I was taken aback
at how much higher the
number was. It didn’t feel like
I was sitting in the gloom
when I was indoors, but all the
readings I took when inside
hovered around the 200 to
500 lux mark, so many times
lower than on the bench.
With my baseline numbers
in, I began to think about how
I could get a bit more sunlight
into my apparently Gollum-like existence (see “Optimise
your exposure”, page 35).
That basically meant getting
outside as much as possible.
I got back in the routine of
cycling part of the way to
work, and although I struggled
to measure the light with my
app while riding, I assume
that helped. I also ate my
lunch outside unless my food
consisted of leftovers that
needed microwaving or it
was freezing or raining.
Unfortunately, in early spring
in London, this turned out to
cover most days.
Could technology help?
I already avoid screens in
the evening, but wondered
whether I could get more
bright light during the day,
even while seated at my
desk. For that I borrowed a
daylight-simulating light
from a firm called Lumie.
The plan was to switch it on
for 10 minutes each morning
to give me a blast of artificial
sunshine. Disappointingly,
my app only registered
about 465 lux, even about
50 centimetres from the light.
That was despite the lamp
being so blinding, it was hard
to work at my computer while
it was on.
In the end, what I learned
seems obvious: I need to
prioritise getting outside
more. In the hustle and bustle
of daily life, it is surprising
just how easy it is to pass day
after day in the indoor gloom.
Joshua HowgegoTRACKING
THE RAYSExtremes of
darkness and
brightness
are key to our
biological
rhythms1 June 2019 | New Scientist | 37>TU
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