- [Narrator] Are you more of an early bird or a night owl?
If you prefer your sunlight in the evenings,
permanent daylight saving time might sound pretty good,
and it could become a reality.
In March 2022, the US Senate approved a bill
to make daylight saving time permanent.
But some experts say it could come at a price to our health.
- I would love to have light in the morning
and in the early evening all year round.
If we were to be on permanent daylight saving time,
you could see where it would be pitch black some places
at eight o'clock in the morning.
- Then people are gonna be commuting
to school and to work in the dark,
and we're gonna be sending our kids
to wait out for the school bus in the dark.
- [Narrator] If the bill becomes law,
it would mean later sunsets, yay.
But also later sunrises, an hour later than usual.
- [Beth] What people have found
when people are going to work in the pitch black
is it actually affects health.
Genes get turned on that normally shouldn't be,
and some of those genes are not operating properly
when we're not in sync with our biological world.
- [Narrator] Early morning light
helps set our internal clocks, or circadian rhythms,
which drive many systems in our bodies
and even tell us when to sleep.
Some research suggests morning light plays a role
in determining when the body releases cortisol,
a stress hormone that makes us more alert.
- We really think of circadian rhythms
as really a fundamental part of life.
That is, it's critical that our biology is, if you will,
in sync with the rising and setting of the sun
in our environment.
- [Narrator] And when morning light is delayed,
our internal clocks are out of step with the sun
in what's called circadian misalignment.
- [Beth] When we're getting our light too late in the day,
not enough light in the morning, and we're losing sleep,
we call it circadian misalignment.
And those things together
can effect health in so many different ways.
- [Narrator] And the effects can be more extreme
depending on where you live in relation to your time zone.
For example, let's look at these two cities,
Indianapolis and Chicago.
Indianapolis is on the western edge
of the eastern time zone.
Confusing, I know, but bear with me here.
And Chicago is on the eastern edge of the central time zone.
So even though they're less than 200 miles apart
and they get similar amounts of sunlight
the time on the clocks is off by an hour.
So when the sun rises in Indianapolis at 7:00 AM,
it's only 6:00 AM in Chicago.
- [Kenneth] And if we look at the health of
people on the western edge versus an eastern edge
that are adjacent to each other,
the people on the western edge have more health problems.
- [Ravi] We know that those who are on
the western part of the time on have higher rates of cancer.
- [Narrator] One study found that
people living on the western edge of a time zone
and get more natural light in the evenings,
got less sleep than their counterparts on the eastern side
and had higher rates of heart disease,
diabetes, and breast cancer.
- [Kenneth] They get less sleep,
higher risk of heart disease, higher risk of cancer,
higher risk of type two diabetes.
We think that if we shift to permanent daylight saving time
that we're going to increase the risk of
these types of problems for our society.
- [Narrator] So what's the science on the healthiest choice?
- It's clear that we should probably
stop shifting every year.
We know that that spring forward shift is associated with
increased risks of motor vehicle accidents,
fatal motor vehicle accidents on our highways,
as well as things like heart attacks and strokes.
- The ideal decision would be
to select permanent standard time.
- [Narrator] But if standard time becomes permanent,
some places, like Boston,
could see summer sun rises as early as 4:00 AM.
But according to science,
all that morning sunlight is critical.
- Permanent standard time is the healthy choice
because morning light is just critical to our health.
It wakes us up, it gets us going.
It helps us fall asleep easier at night.
So having that bright morning light is
really, really essential,
particularly for people who can't control their schedules,
like teenagers and some of our essential workers.
- [Kenneth] So when we're thinking about
permanent daylight save time,
we're gonna go ahead and
gain light one way and lose light another.
And so we have to decide as a society
what is gonna be the healthiest thing for our society.
(playful orchestral music)