Don't use your phone before going to bed! The ISS study explains

"Has anyone ever told you not to use your cell phone before going to bed? This is because blue light affects your circadian rhythm, your natural response to changes in daylight," says a message published on ESA's profile on the X platform.

European Space Agency (ESA) astronaut Andreas Mogensen is currently conducting sleep-related research on the ISS, and his mission, called Huginn, actually consists of two studies aimed at better understanding circadian light and sleep in orbit .

“Astronauts on the ISS make a complete circle around Earth every 90 minutes and experience 16 sunrises and sunsets each day. Because of this 'irregular' routine, astronauts can struggle to find a natural daily rhythm in space. "The ISS follows GMT time zone, which helps maintain a consistent schedule, along with regular wake-up and bedtime routines," ESA said in a statement.

Circadian rhythms are natural physical, mental, and behavioral processes that follow a 24-hour cycle and respond primarily to light and darkness. They affect most living things including animals, plants and microbes.

In space, these rhythms are distorted, meaning astronauts can suffer from insomnia and inadequate, restless sleep. To avoid these consequences, Mogensen uses a special light, developed by the Danish company SADA Space Architects. The system consists of a special lamp designed to support the circulatory rhythm of astronauts in space.

In the evening, when Mogensen wants to sleep, the light turns red, just like a sunset, while in the morning it turns blue, simulating a sunrise on a clear day.

For the in-orbit sleep study, Mogensen also uses an ear-mounted measuring device that monitors his brain's electroencephalogram (EEG). The invention is the work of researchers from Aarhus University in Denmark and allows them to assess his brain activity at night.

The researchers of these two studies are working together to collect as much data as possible and to better understand sleep in space, but also on Earth. The results are particularly relevant today, as research shows that climate change is also disrupting our sleep patterns.

Research in 2022 showed that due to global warming, humanity is losing essential sleep and that the effect is worst for people from developing countries.

"Our results show that sleep, a key restorative process that is part of human health and productivity, can be degraded by warmer temperatures. Across different seasons, demographics, and climate contexts, warmer outdoor temperatures consistently disrupt sleep and sleep quantity. the loss increases progressively with age and temperature," said lead study author Kelton Minor.

Although the ESA studies do not take warmer temperatures into account, the results may offer tips and suggestions for better sleep, or ways to combat sleep loss caused by a warmer climate. Since the studies are conducted in extreme space conditions, they may offer solutions to sleep deprivation caused by extreme weather conditions.