Too much light at night, and too little light during the day, could increase the risk of dying earlier than you would otherwise – a reminder of the importance of healthy sleep and following the cues of our circadian rhythm.
From working night shifts or staying up late watching television, to being hidden in offices or homes during the day, the habits and routines of modern life tend to disrupt a more natural relationship with light and dark.
And that is potentially fatal, according to the international team of researchers behind the new study. It adds to what we already know about the relationship between artificial light and a variety of health risks.
“Exposure to brighter nights and darker days can disrupt our circadian rhythm, a disruption known to lead to several health problems including diabetes, obesity, cardiovascular disease, mental health problems and increase the risk of death,” says the senior author of the research. sleep scientist Sean Cain, from Flinders University in Australia.
“These new insights into the potential negative impact of light have shown us how important personal light exposure patterns are for your health.”
The researchers looked at data in a British research database and collected information on 88,905 people who had worn light sensor trackers for a week, with their health then tracked for about eight years.
Here are the raw statistics: exposure to a lot of light at night was linked to a 21 to 34 percent increased risk of death, while exposure to a lot of daylight during the day was linked to a 17 to 34 percent lower risk of death.
A study like this isn’t enough to prove direct cause and effect – there are too many other potential contributing factors to consider – but the connection is strong enough to suggest that light cycles are somehow linked to health and the mortality rate.
“Protection of lighting environments may be particularly important in people at risk of both circadian disruption and mortality, such as in intensive care or aged care,” says lead author and sleep scientist Daniel Windred from Flinders University.
Further computer modeling showed that the strength and rhythm of participants’ circadian rhythms – likely influenced by patterns of light exposure – were also linked to mortality, supporting the idea that it is the disruption of the body’s natural flow which increases the risk of serious diseases. , and from there an earlier death.
While it’s disturbing to hear that this aspect of our modern lifestyle could send us to an early grave, the good news is that the problem isn’t that difficult to tackle: getting more daylight and avoiding light at night is something that we can all try. .
“Our findings clearly show that avoiding night light and seeking daylight can promote optimal health and longevity, and this recommendation is easy, accessible and cost-effective,” says sleep scientist Andrew Phillips from Flinders University.
The research was published in PNAS.