Daylight Saving Time: A Jolt Forward



LIGHT HELPS CONQUER the blues, cope with jet lag and shed excess weight.  Certain cancers, heart disease and diabetes as well as depression have been linked to disturbances of circadian rhythms – which can be rejiggered using light.

The best light to combat ills is the light of early morning, from 6 to 9 a.m.  Not for everyone, especially when Daylight Saving Time jolts us ahead an hour – for some, stealing a precious hour of the Sunday sleep-in.

To conquer the daylight-saving yawns, some tips from WebMD:

  • Expose yourself to light — as much as possible and as early as possible — during waking hours, and as little as possible when it’s dark outdoors. If you get up during the night, do not turn on a light: set up a night-light ahead of time if necessary. For added help, use “light therapy” (see below), especially during the morning hours.
  • Practice “sleep hygiene:” reduce or eliminate caffeine and alcohol, create calming rituals before bed (like a hot bath), wear ear plugs and eye masks. Consuming carbohydrates in the evening may make it easier to fall asleep compared to large protein meals.
  • Try exercising four to five hours before bedtime: 20 to 30 minutes of vigorous exercise raises the body temperature as much as two degrees, for up to five hours, after which it drops lower than without exercise. Decreased body temperature is a signal to the body that it’s time to sleep. (Conversely, exercising within three hours of bedtime can stave off sleep.)


Called “blue light,” early morning light contains more wavelengths in the blue portion of the spectrum than light at other hours.  Blue light inhibits the creation of melatonin in the brain, which tells the body it’s daytime.

Mathematicians at the University of Michigan have created an iPhone app called Entrain:  “entrainment” refers to synchronizing circadian rhythms with the actual time of day wherever you are.  If your rhythms are off – due to shift work or travel across time zones – the app can schedule blocks of time each day when you should be exposed to the brightest or the least light possible.  If initially that schedule does not synch with the outdoor light in your location, you can substitute a light box like the Verilux (see below) for the hours you are meant to spend in sunlight; to create dark periods when it’s daytime, wear pink glasses to block out the blue wavelengths.

Blue light also affects metabolism, including the hormones that control appetite.  In a Russian study of obese women, exposure to bright morning light lowered their percentage of fat, their fat mass and their appetite, compared to a control group exposed to a machine emitting ions instead of light – although the light did not significantly affect their weight.

Fifty-four volunteers at Northwestern University’s School of Medicine wore wrist monitors that measured their light exposure as well as their sleep patterns and kept a log of everything they ate and drank over a seven-day period.  For every hour that light exposure was delayed, subjects’ BMI rose 1.28 points, according to results published in the journal PLOS One.

Luckily for us night owls, light exposure any time throughout the day helps regulate body weight.   The most important variables in the Northwestern study were: light of at least 500 lux, which exists naturally around sunrise and sunset; and exposure as early in the day as possible. Lux is a measurement of a light’s intensity related to size of the area illuminated;  full daylight provides about 10,000 lux and direct sunlight, 32,000 to 100,000 lux, but even a cloudy day can measure 1,000 lux.

For those who use computers, cell phones or e-readers into the early morning hours, there is the F.lux software or app that can be used for most electronic screens to adjust the monitor display’s “color temperature.” The colors — ranging from cooler (white through bluish white) to warmer (yellowish white through red) – change based on the device’s location and the time of day.

F.lux, which also reduces eye strain, is “freeware,” available at JustGetFlux, and has thousands of enthusiasts. Sleep Junkies blogger Jeff Mann writes that it took him a day or two to adjust to the new evening hue, which looked “a little more ‘red…’” but now he would “find it almost unimaginable to go back to my pre-F.lux display settings.”  Without F.lux, Mann writes, to use a computer at night is like “staring at the sun.”

Circadian clocks present in almost every cell and tissue of our bodies orchestrate daily rhythms in sleep/wake patterns and metabolism.  Researchers at England’s University of Manchester have discovered that an enzyme called CK1epsilon (casein kinase 1 epsilon) controls the ease with which our bodies’ clocks can be reset by environmental cues, including light and temperature.  Drugs that that inhibit this enzyme allow for faster resetting of the circadian clocks in mice and may one day help people with the nasty effects of jet lag.

Then there’s “light therapy.” One winter, my son (then in middle school) and I began struggling with the long, dark days.  Getting out of bed in the morning became a bigger challenge until I bought us each a SunRise Alarm clock with a light that starts brightening 30 minutes before your wake-time and reaches 250 lux.   I also got a small Verilux lamp that weighs in at 5,000 lux to sit on my desk.  We both felt better.  Even now, years later, if my attic office feels a little gloomy, I turn on the Verilux, and my day improves.

So, when you need a light boost, plan to spend time outdoors.  But for short days or bad weather, don’t forget about the SunRise and the Verilux — with one caveat: when Floridian Alissa Nutting was transplanted to Cleveland, what her psychiatrist called “happy lamps” fell short.  Writing a New York Times Op-ed, Nutting described the lamps as having a “low-calorie feel…the wavelength equivalent of margarine.”  In the end, she decided to treat the lamps’ light as a “supplement rather than a replacement, and now the moment I turn on the lamp and light floods throughout the room, I can’t help thinking, something is happening in here.”

Come spring, however, Nutting can’t wait to pack the lamp back in its box and return to the real outdoors. Here’s hoping Spring is right around the corner in our neck of the woods.


–Mary Carpenter




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