Get laptops and tablets out of the bedroom.

Blue light hurts circadian rhythms.

The pineal gland is a small, pine cone-shaped structure near the center of the brain that secretes the hormone melatonin at night in response to darkness. While the pineal gland is sensitive to all wavelengths of light, blue light in particular (460-480 nanometers) suppresses melatonin release proportional to both the intensity and duration of the light exposure. 

A 2006 study by Steven Lockley and colleagues at Harvard found that when participants were exposed to 6.5 hours of either blue or green light, blue light suppressed melatonin twice as long, shifting the circadian rhythm by 3 hours (versus 1.5 hours with green light). 

Blue light exposure also reduced delta, or “deep,” sleep at night.

Regardless of intensity, blue light—like that emitted from television, computer, tablet, e-reader, and phone screens—is wrecking our natural sleep and circadian rhythms. 

It’s estimated that 95% of Americans use some sort of electronic device at least one hour before bedtime. A study by Anne-Marie Chang and colleagues published in December found that, compared to reading a paper book before bed, reading from an iPad increases sleep latency, decreases REM sleep, and enhances feelings of sleepiness during the day, even when both groups sleep the same duration the night before.

Shut off the screens at night, Mr. President and First Lady. If you must work so late, consider downloading the application f.lux or investing in a pair of orange glasses to block out the blue.

Exercise is great, but not at the expense of sleep

Rarely do we see Claire run in daylight. In earlier seasons, she bustles around the kitchen in the wee hours of the morning in running spandex, and is later seen darting headstones in the dark graveyard. In the middle of Season 3, we watch Claire go for a midnight run to ward off stress, flanked by security. And with his late-night indoor rowing habit, Frank isn’t off the hook either. The Underwoods are busy public figures, and incorporating vigorous exercise into their hectic schedules is to be commended – but not at the expense of their sleep.

Exercise is great for sleep. Indeed, a 2011 study reported that 150 minutes of moderate to vigorous physical activity per week improve can improve sleep quality by 65%. Using actigraphy, study authors Paul Loprinzi and Brad Cardinal examined the exercise habits of over 3,000 adult men and women. Those who met minimum physical activity requirements reported less daytime sleepiness and better overall sleep quality, regardless of factors like age, body weight, and depression. Similar findings on the benefits of exercise on sleep were reported by the National Sleep Foundation’s 2013 Sleep in America poll.

The timing of exercise is a little more controversial. It’s a common sentiment that late-night exercise destroys sleep. After all, exercise ramps up your heart rate, raises body temperature, and causes release of the stress hormone adrenaline, making us active and alert. A 2011 study, however, reported that participants slept just as well on nights when they exercised just half an hour before bed as they did on nights when they didn’t exercise at all. For those prone to bouts of insomnia, though, most sleep physicians recommend not exercising for several hours before bed.

Kudos on your exercise habits, Frank and Claire. You’re way more disciplined than I am. Just work on the timing a bit, okay?