On Earth, we experience disruptions to our circadian rhythm – the body’s regulator for sleep and wake cycles based on a 24-hour schedule – due to abnormal work schedules or traveling between time zones. Now think of astronauts aboard the International Space Station (ISS) who orbit Earth every 90 minutes. Crew members see 16 sunrises each day! The frequent change from darkness to light severely disrupts the body’s natural circadian rhythm, and that can mean loss of sleep for astronauts, who, studies have shown, sleep considerably less in space than they do on Earth.
The new ScienceCast video above, released by NASA in late 2016, describes how researchers are trying to find out how different light spectra can be used to help astronauts both be more alert when needed, and get a better night’s sleep.
The new study is called the Lighting Effects Study, and, as a first step, it’s replacing old fluorescent lights on ISS with special LEDs that can be shifted into low-, high- or normal-intensity modes to match the astronaut’s need for more alertness, or to prepare for a long snooze.
The new study is expected to define protocols for lighting in future space missions.
And the results should have significance for us on Earth, too. Down here on our planet, as in space, circadian misalignment and sleep deficiency can lead to significant, fatigue-induced errors and even chronic disease. The results of this ongoing NASA study should make it clear how and when various settings of light intensity – and the light spectrum – can be used to promote sleep and alertness. This may lead to help for those who suffer sleep disorders, and may even lead to treatments for jet lag.
To learn more about the new sleep study, watch the video above.
And to learn what NASA has already learned about sleep for its astronauts and ground-based shift workers, read more from NASA
Bottom line: Astronauts aboard ISS experience 16 sunrises and sunsets a day. Studies have shown their sleep patterns can be affected. A new NASA study is investigating how different light intensities and spectra can be used to help regulate astronauts’ patterns of alertness and sleep.
Eleanor Imster has helped write and edit EarthSky since 1995. She was an integral part of the award-winning EarthSky radio series almost since it began until it ended in 2013. Today, as Lead Editor at EarthSky.org, she helps present the science and nature stories and photos you enjoy. She also serves as one of the voices of EarthSky on social media platforms including Facebook, Twitter and G+. She and her husband live in Tennessee and have two grown sons.