- Sunlight exposure
The sun plays a significant role in regulating melatonin and the circadian rhythm. Exposure to natural sunlight, particularly in the morning and evening, helps to synchronize the body's sleep-wake cycle with the external environment. Although natural sunlight includes wavelengths of blue light, it differs from artificial light as it is accompanied by a balance of other wavelengths in the visible light spectrum. This includes an equal amount of infrared, red, yellow, orange, and UV wavelengths, which is known as the full light spectrum. The balance of these different colours varies throughout the day.
Exposure to natural sunlight in the morning, during the first few hours after waking up has much less blue light and more red and infrared, this helps gently suppress melatonin production, signalling to the body that it's daytime, promoting wakefulness.
Exposure to natural light during the day has a balanced level of blue light and UV, this supports the maintenance of a healthy circadian rhythm and helps reinforce the body's natural sleep-wake cycle contributing to alertness and overall well-being.
As the day progresses, the sunset will shift again to a higher amount of infrared and red light signalling to the pineal gland to start producing melatonin. This rise in melatonin levels helps prepare the body for sleep making it easier to fall asleep, improve the quality of sleep, and feeling energised after waking.
Natural blue light from the sun has been shown to have positive impacts on mood regulation, motivation and energy levels. The presence of blue light plays a crucial role in regulating our circadian rhythms.
In the morning, when natural blue light from the sun enters our eyes, it sends a signal to the brain that the day has started, and that it's time to feel awake, alert, and energised. This natural regulation of our body clocks is necessary for maintaining optimal physical, and emotional health.
Additionally, this kind blue light exposure has been linked to an increase in the levels of neurotransmitters such as dopamine and serotonin. These chemicals in the brain are responsible for regulating mood, emotions, and overall well-being. On the other hand, the onset of darkness and the absence of blue light in our environment signal the brain that it’s time to shift to a more relaxed state, this is done by a necessary increase in melatonin production. The release of melatonin causes us to fell relaxed and drowsy, which is essential for getting a deep and replenishing sleep.
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- REM sleep and why is it important
REM (Rapid Eye Movement) sleep is one of the stages of sleep that occurs cyclically throughout the night. It is characterized by rapid movement of the eyes, vivid dreaming, and heightened brain activity. During REM sleep, the brain is as active as it is when you’re awake. This is because REM sleep plays a crucial role in memory consolidation, it helps to process and store information gathered throughout the day, promoting learning and cognitive functions including problem-solving and creativity. It’s linked to emotional regulation and resilience, as it allows the brain to process and make sense of emotions. REM sleep is associated with physiological restoration, like the repair of tissues, strengthening of the immune system, and the maintenance of overall bodily functions. Disruptions in REM sleep have been linked to certain mental health issues, including depression and anxiety.
Exposure to blue light emitted from screens, especially in the evening, significantly impacts the initiation, duration and transition through REM sleep cycles. The suppression of sleep-inducing hormones such as melatonin disrupts the body’s sleep-wake cycle leading to heightened alertness and states of wakefulness, impacting the transition into REM sleep as well as the duration and quality.