Adjusting to ‘Mars time’ with coffee, naps, and bright blue light

As NASA’s Mars rover Curiosity continues its meandering route across the planet’s rocky surface, a team of engineers and scientists back on Earth are having their own Martian experience: They’re learning to live on “Mars time” by adjusting to its slightly longer, 24.65-hour day.

Those extra 39 minutes and 35 seconds may seem like a small difference, one easily absorbed into the variable nightly sleep schedule of the average human. But it’s not a one-time change like jet lag; instead, it’s like traveling across a time zone every single day. So adjusting to even a slight change in schedule is difficult for people to deal with.

Because we have evolved within a 24-hour day, our bodies are tightly synchronized with that schedule. Deviating from it has been shown to lead to sleepiness, difficulty thinking and solving problems, and even workplace accidents -- something no one wants to happen while they’re planning the next movements for the $2.5-billion mission.

Now, researchers have discovered a specific set of interventions that appears to help people synchronize their circadian clocks anew. In a study published Friday in the journal Sleep, scientists report that a combination of training and exposure to shortwave blue light improved the sleep-wake patterns of a small group of NASA employees who worked on the Mars Phoenix rover project.


In the study, the entire NASA team received training in ways to effectively reset their clocks, including how to drink coffee at the right time, how to nap, and -- most importantly -- when it was useful to be exposed to bright light. Then a group of 19 employees was given a blue light for their desks. Blue light was chosen because it has a relatively short wavelength, and research has shown that shortwave light has the most impact on the circadian rhythm. It also affects levels of melatonin -- a key circadian molecule that is released at night and leads to sleepiness.

When the researchers did a chemical urine analysis to determine whether the subjects’ bodies had begun to adhere to the length of the Martian day, they found that 13 out of 15 subjects who received training and the light had begun to live on Mars time. What’s more, the subjects who had synchronized successfully slept an hour more per night than those who did not -- though neither group slept as much as they should have, coming in at about six hours a night for the successful subjects and just under five for the subjects who failed to adjust to the new schedule.

The results suggest that it’s not impossible to adjust to a new circadian schedule: For most, the combination of simple interventions, like naps and coffee, combined with technologically advanced ones, like short wavelength desk lights, did the trick.

That’s good news for NASA rover employees, whose job is hard enough already: The study also reports that many of the subjects regularly worked 21-hour days, so they’ll need all the sleep they can get.


For a personal look at what it’s like to live in Mars time, check out this story from Times staff writer Amina Khan.

You can read a summary of the study here.

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