Exposure to sunlight is beneficial for health, and not only because we need it for the body to synthesize vitamin D, but because it also helps improve our mood, since our biological clocks or circadian rhythms that mark the moments Sleep and wakefulness are associated with the hours of light and darkness and a lack of light can contribute to the appearance of emotional problems.
However, too much light exposure at night can have negative consequences. And this is demonstrated by the largest study carried out so far on light exposure and its impact on mental health, in which 86,722 adults participated, with an average age of 62.4 years (57% women). Their results have shown, in particular, that greater exposure to light at night increases a person’s risk of suffering from psychiatric illnesses such as anxiety, bipolar disorder and post-traumatic stress disorder, as well as self-harm.
The research has been led by Sean Cain, associate professor at the School of Psychological Sciences at Monash and the Turner Institute for Brain and Mental Health in Melbourne, Australia, and the researchers also found that greater exposure to daylight can work as a non-pharmacological method to reduce the risk of psychosis.
How to expose yourself to light to prevent mental disorders
The risk of depression increased by 30% in participants who were exposed to large amounts of light during the night, while the risk of depression decreased by 20% in those who were exposed to large amounts of light during the day. Similar patterns of results were observed for self-injurious behavior, psychosis, bipolar disorder, generalized anxiety disorder, and post-traumatic stress disorder.
Avoiding light at night and exposing yourself to brighter light during the day could be very helpful in reducing serious mental health problems
The findings have been published in Nature Mental Health and reveal that a practice as simple as avoiding light at night and exposing yourself to brighter light during the day could go a long way in reducing serious mental health problems. “Once people understand that their light exposure patterns have a powerful influence on their mental health, they can take some simple steps to optimize their well-being. “It’s about having bright light during the day and darkness at night,” said Professor Cain.
All study participants were from the UK Biobank and were screened for their light exposure, sleep, physical activity and mental health. Cain has highlighted that the impact of nighttime light exposure was also independent of demographics, physical activity, season and employment: “And our findings were consistent when taking into account shift work, sleep, life urban versus rural and cardiometabolic health.
Our current lifestyle is disrupting our biological systems, because, as Cain points out, our brains evolved to function best in bright light during the day and almost no light at night. “Today, humans defy this biology and spend about 90% of the day indoors under electric lighting that is too dim during the day and too bright at night compared to natural light and dark cycles. It confuses our bodies and makes us feel bad,” he concludes.
