We know more and more about circadian rhythms here on Earth, where the sun rises and sets in manageable and predictable (we hope) twenty-four hour cycles. Space though is another matter altogether.
In space the sun rises and sets every 90 minutes, a dizzying speed that destroys settled circadian rhythms and pushes sleeping patterns out the window. Now scientists are trying to address this problem and LED is providing the answers.
Researchers at the Light Research Program at Thomas Jefferson University in Philadelphia have discovered that sleep time on the International Space Station falls from an Earth average of eight hours to six.
This may not sound like a lot, but when it continues week after week, it can lead to serious fatigue, increasing the chance of mistakes in a seriously hazardous environment.
In response to this, as our sister publication LEDs Magazine reported, scientists from Harvard University and NASA’s Johnson Space Centre are sending LED-based circadian lighting to the International Space Station.
The team have created a system of tuneable LED lights that have three basic settings, general vision for most of the day, circadian phase shifting/acute alerting when required, and a pre-sleep setting to prompt sleepiness when it is time to rest.
There is no such thing as an average day on the ISS and work schedules chop and change to suit the mission. In such cases, when faced with an erratic work schedule, the astronauts can use the shifting/acute alerting setting to give them a boost.
Alternatively pre-sleep mode might be chosen, which is skewed towards a mix of warm colour temperatures that ease the mind into a relaxed zone, prompting sleep to come easily.
The LED will start arriving on the ISS this month, when the first set of lighting will be placed in the astronaut’s sleeping quarters, where it will replace a fluorescent system.
If the lights work and increase the hours of sleep that the astronauts can get, then it will be the strongest evidence in favour of the importance of circadian rhythms to date.
- You can find out more about circadian rhythms at this year's Lux Live. The exhibition will take place in London on Wednesday 23 November and Thursday 24 November 2016. You can find out more by clicking here.