1. The Impact of Daylight on Our Circadian Rhythm
The human body’s 24-hour cycle is regulated by light, which is why it’s essential to make the most of natural daylight. According to Dr Christine Blume, a sleep scientist at the University of Basel, Switzerland, daylight sensitivity is a part of our biological clock. The circadian pacemaker controls the 24-hour cycle and is located in the suprachiasmatic nucleus (SCN) in the brain’s hypothalamus.
A non-image-forming light-sensitive cell in the eyes is especially sensitive to short wavelengths like blue, which is abundant in the morning and the middle of the day. This light induces a phase advance that sets the internal biological clock to help us become tired earlier in the evening. Evidence has shown that exposure to morning light can effectively treat seasonal affective disorder (SAD), perinatal depression, bipolar depression, eating disorders, and ADHD.
2. The Importance of Daylight for Quality Sleep
Getting enough natural light during the day is crucial for quality sleep at night. Sleep deprivation affects the processing of emotional memory, resulting in a tendency to select and remember negative memories after inadequate sleep. It also impairs your ability to concentrate, learn, and remember. Without sleep, your immune system cannot produce protective, infection-fighting antibodies and cytokines, leaving you vulnerable to infections.
Hormone production is also influenced by sleep. A lack of sleep decreases the levels of leptin, which tells your brain that you’re full, and increases ghrelin, the “hunger hormone.” Daylight helps regulate hormonal activity, digestion, and other essential body functions.
3. Why We Should Make the Most of Daylight
A disrupted circadian rhythm is associated with a range of health problems, including cardiovascular dysfunction, cancer, reproductive problems, and neurodegenerative diseases like dementia. Daylight provides a wealth of health benefits, like boosting mental performance, alertness, mood, and energy levels. It reduces chronic pain while reducing the side effects of pharmaceutical antidepressants.
Vitamin D is also necessary for optimal health, and it’s produced when sunlight hits the skin. It helps the body absorb and retain calcium and phosphorus, which are critical for building strong bones. Vitamin D also reduces cancer cell growth, controls infections and reduces inflammation.
4. How to Optimize Your Daylight Exposure
Most of us are neither larks nor owls, but somewhere in between, and it’s relatively easy to retrain our circadian rhythm by restricting light in the evening and going to bed earlier. Getting outdoors is key to optimizing your daylight exposure, especially in the morning. Sunlight is much brighter outside than indoors, even on an overcast day, and brings other benefits like fresh air and nature exposure.
Blume recommends optimizing your daylight exposure by getting lots of natural light in the morning and avoiding artificial light in the evening to reset your biological clock to a more socially acceptable timetable.
Daylight has a significant impact on our circadian rhythm, hormones, and overall health. Making the most of natural light can help optimize our physical and mental function, while optimizing our daylight exposure can lead to a better quality of life. By taking small steps to optimize our daylight exposure, we can help our bodies function optimally and promote overall health and well-being.