Every year, twice a year, in most of the United States, Americans are forced to switch their clocks back and forth an hour due to the strange, uniquely American ritual known as Daylight Saving Time, or DST.
And every year, twice a year, the clock-changing ritual of DST has been shown to take a detrimental effect on Americans across the country.
But while blaming DST is common for various issues, Circadian rhythms expert and engineer Willem Sillevis Smitt, a senior director of strategic marketing at Lumileds, said people can avoid the issues by adjusting the brightness and colors of the artificial lights they expose themselves to in the evening.
"When I look at how people report the impact of daylight saving, it mostly impacts how people sleep," said Smitt, an expert in "human-centric lighting. "Most of us go to bed way after 7 p.m., when it's already dark. So my conclusion was that the impact must come not so much from sunset and sunrise, but more from how we keep the lights on in the evening."
To help ease into the evening, Smitt recommends making sure the lights are warm and dimming the lights a bit as darkness falls.
The company has been developing lights that automatically dim themselves based on the time of day, and which shift from a bluer light during day-time to a more orange light at night.
"Human beings evolved with very bright light levels during the day and very dark levels at night. ... If it's a nice day, we're under the blue sky. How we evolved during the night, if there was any light, it tended to be fire," Smitt said. "The technology that we developed has the ability to have a different color during the day and during the night, to match this light pattern that we evolved with."
It's the same principle behind the iPhone's "Night Shift" feature that adjusts light based on the time of day, to help prevent users from giving themselves insomnia by staring at a bright white screen late into the night.
But beyond just color, Smitt said Lumileds technology is optimized to spectral output that best resembles natural light and has the most beneficial effect on human test subjects.
"In the evening, you want to limit and especially wind down the light levels as the melatonin [the natural hormone associated with sleep onset] starts to come up a little bit," "This is why winding down is so important if you want to have a good night's sleep [which] really helps to feel good, to be active, and have a good mood, research shows."
Origins of a ritual
Daylight Saving Time (DST) was officially enacted nationwide in 1966, purportedly to give farmers extra hours of daylight, although many pointed out that farmers just wake up when the sun rises.
But in fact, in Indiana, agricultural regions refuse to participate, precisely because DST makes farmers' lives harder. And the great states of Arizona and Hawaii permanently refuse to acknowledge DST.
Massachusetts recently convened a state commission to investigate the idea of ending DST, which found there would be "positive benefits" with making the November clock-change permanent, but only if other states made the same change simultaneously, to prevent interstate confusion.
As of 2018, there are dozens of petitions on Change.org to end DST. The Standard Time movement says DST is causing chaos and must be ended. Organizers with the #LockTheClock movement urge anyone with anti-DST leanings to contact their state and local legislators.