How Does Your Light Environment Impact ADHD, Sleep & Mental Health?
On reviewing the literature it’s clear that mental health disorders are more often than not tied to poor sleep quality and disrupted circadian rhythms. Our circadian rhythms are tied to the natural cycles of light and dark which means the wrong type of light at the wrong time of day or night can disrupt our circadian rhythms and thereby impact our sleep negatively.
Our brains are signalled to suppress melatonin production when exposed to artificial blue and green light in the 400-550nm range after sunset which then makes it challenging to get high quality, restorative sleep.
According to Harvard Health, a healthy sleep cycle is one that lasts 90 minutes and goes through light, REM and deep sleep phases. These phases then release the appropriate levels of neurotransmitters needed for mental wellbeing. (1)
A lack of natural light exposure also disrupts our circadian rhythms as our brains consequently lose out on important light messages through non-visual receptors in the eye called ipRGCs and melanopsin.
Sunlight also releases serotonin and dopamine, elevating mood and helping us sleep later in the evening. Minimising sun exposure either consciously or sub-consciously, combined with increasing time spent under artificial light is disrupting our body clocks, wrecking our sleep and leading to steep rises in mental illness across the world.
Attention Deficit Hyperactive Disorder (ADHD)
According to the CDC in 2015 1 in 10 children between the ages of 5-17 are now diagnosed with ADHD. (2)
Numerous studies show disrupted circadian rhythms and poor sleep often go hand-in-hand with ADHD. This has also been seen in studies showing symptoms of ADHD can be seen in children without ADHD. Lack of sleep in neurotypical children, and indeed the majority of people, often results in poor attention span and lack of focus the next day. It has also become very clear in the literature that poor sleep can exacerbate symptoms of ADHD while on the flip-side improving sleep and circadian rhythms can improve ADHD. (3)
Studies have been carried out with children with ADHD by getting them to wear blue light blocking glasses in the evenings before bed. The results showed a statistically significant decrease in anxiety and improved sleep quality. They also went to bed earlier when wearing the blue light blocking glasses. (4)
This type of study shows us that sleep and disrupted circadian rhythms have a huge role to play in children with ADHD. A disrupted circadian clock and poor sleep is tied to exposure to blue and green light after dark, lack of sunlight during the day and overexposure to blue light during the day from artificial sources such as screens.
Anxiety and Depression
Studies using different methods and populations estimate that 65% to 90% of adult patients with major depression and about 90% of children with this disorder also experience some kind of sleep problem. (5)
Anxiety and depression are on the rise with sadly even more cases in children. Mental Health America states a 37% increase of reported mood disorder symptoms among young people over a 9-year period. (6)
Blue light exposure is linked to mood disorders which include disruption of brain plasticity, neurotransmission, hormone secretion and gene expression.
Lack of sleep caused by exposure to blue light after dark had been shown in studies to disrupt the cortisol cycle. Cortisol should be highest in the mornings and lowest at night. But, disrupted sleep and circadian rhythms can reverse this cycle, which can then increase your susceptibility to anxiety, stress or depression. (7)
Anxiety and depression can be regulated through correct circadian cycles of dopamine and serotonin. Sunlight increases these two neurotransmitters, so missing out on morning sunlight could be increasing your risk of anxiety and depression! Being inside at the office, school or home and exposing yourself to artificial blue light disrupts your sleep, but missing out on sunlight at the same time is just as detrimental to your mental health.
Serotonin also has another function which is to react with tryptophan in the gut later in the evening. In the absence of blue and green light, it creates melatonin, not only helping us sleep but acting as a potent antioxidant, helping clear waste products from our body and fight inflammation. Higher levels of inflammation have been linked to metabolic and neurological diseases.
Harvard Health has also shown those with a sleep issue are four times more likely to develop depression and people with depression almost always have a sleep issue.
Seasonal Affective Disorder (S.A.D)
S.A.D is personified by feelings of low mood in winter months. Incidences of S.A.D can be correlated to long periods of no sun exposure which is why its typically common in winter months.
During these months we are often exposed to even more artificial blue light as days shorten and we stay inside due to the cold weather. This is a double whammy on our mental health as we are disrupting our body clocks through excess exposure to artificial light but also missing out on sunlight, which we know is essential for elevated mood, improved mental wellbeing and better sleep.
The best ways to counteract the negative effects of S.A.D are firstly to get sunlight during the day. It doesn’t matter if it’s cold or cloudy, just being outside during the day allowing your skin and eyes to absorb natural light is enough to increase dopamine and serotonin production. Secondly, allow these neurotransmitters to do their job post-sunset by blocking blue and green light from artificial sources.
Wearing 100% blue/green light blocking glasses is a great way to improve sleep and reduce symptoms of S.A.D.
Blue light from S.A.D lamps have been shown in the literature to improve mood. However, this is an unnatural short-term fix that if administered over long periods could lead to circadian disruption, poor sleep and eventually other related mental health issues such as those described above.
In the Northern Hemisphere it’s hard to get outside during winter months. Daylight saving and the reduction in actual daytime mean we often arrive at work when it’s dark, work under artificial light all day and then return home after sunset. It’s important that if this sounds like your winter days Monday to Friday, you get outside for natural light breaks whenever you can.
Thank you for taking the time to read this article. Mental health is on the rise and we need to ensure we fight against it. Many people around you will need your support, so make sure you offer compassion, love and words of positivity to them to help them during these hard times.
- CDC, 2015. Percentage of Children Aged 5–17 Years with Diagnosed Attention Deficit/Hyperactivity Disorder (ADHD). Morbidity and Mortality Weekly Report (MMWR). October 16, 2015 / 64(40);1156.
- Cortese, S., 2015. Sleep and ADHD: What We Know and What We Do Not Know. Sleep Medicine, 16(1), pp.5-6.
The author, Andy Mant, is the Founder & Director of BLUblox. His passion is researching and educating to help empower others to lead an optimal and fulfilling life. He wants to make the science behind light management understandable to all by offering digestible information that people can utilise. He designs products in line with proven academic literature to ensure BLUblox customers get only the best available technology that will actually make a difference to their health and wellbeing.