Before the invention of artificial lighting, humans used the sun as their main light source. When the sun went down, they had to spend their evenings in the dark (and adjusted their work and sleep routines accordingly). Flash forward to our current day and — thanks to innovations like the smartphone — most of us have a convenient little "light source" with us at all times. While there's no doubt that technology serves us in many ways, regular exposure to so much artificial light (especially during evening hours) can do a number on your sleep health. Since sleep is crucial to your overall mental, physical and emotional well-being, it's time to look into resetting your circadian rhythm if you struggle to get or stay asleep.
What Is Circadian Rhythm?
Our sleep-wake cycle is determined by the body's circadian rhythm — an internal biological "clock" that helps our bodies maintain a regular routine, which promotes all sorts of functions, including healthy sleep. In a normal circadian cycle, the body is able to monitor certain environmental changes (such as darkness and light changes) and respond by producing hormones to help the body perform the correct functions at the appropriate time. For example, when you are exposed to light in the morning, your body should naturally produce more cortisol — helping you stay alert and awake. In contrast, your body should produce more melatonin (a hormone that induces sleepiness) at night.
What Happens When You Become Out-of-Sync?
When your sleep schedule becomes misaligned from your normal circadian cycle, you can end up feeling out-of-sync with your body. You've likely experienced this feeling after working a night shift or taking a long flight and experiencing jet lag. Fortunately, small interruptions to your sleep cycle likely won't set you back too far. However, frequent disruptions to your normal circadian rhythm can cause a host of health concerns, including chronic insomnia, lack of energy, daytime sleepiness and depression. Long-term disruptions to your body's internal clock can increase your risk for obesity, cardiovascular disease, diabetes, gastrointestinal problems, neurodegenerative disorders (including dementia), skin issues and more.
Let's Talk About Blue Light
On the light spectrum, blue light falls between 415 nanometers (nm) and 455 nm, meaning that it has more energy than other types of light waves. During daylight hours, we are exposed to blue light from the sun, which helps boost our attention, reaction times and mood while synchronizing our body's circadian cycle. However, with the proliferation of electronic screens and energy-efficient lighting (which emit large amounts of blue light), we are blasted with an overabundance of blue light practically everywhere we turn.
According to a study from the National Center for Biotechnology Information, blue light exposure can heighten visual fatigue, nearsightedness and even have an impact on learning and work performance. Overexposure to blue light after sundown can be particularly disruptive to your body's natural functions — especially your sleep hygiene. With electronics and artificial lighting being such common parts of our evening routines, it's no wonder why so many of us struggle with sleep issues! In fact, according to the Centers for Disease Control and Prevention (CDC), approximately 70 million Americans suffer from chronic sleep problems.
Your Health Hack for 2023: Rise & Shine
There are plenty of ways to manage the effects of blue light exposure — namely limiting your screen time in the hours before bed — but let's focus on one specific tip for resetting your internal clock. According to Stanford neuroscientist Dr. Andrew Huberman, getting outside and exposing yourself to natural sunlight shortly after waking up is one of the best things you can do to improve your sleep quality and overall well-being. The motto? Sunlight before screen light. Essentially, the goal is to trigger your body's natural response to sunlight, causing it to release cortisol (the "wake up" hormone) into your system and signaling the start of a new day. Early morning exposure to sunlight also starts your body's timer for the onset of melatonin (the "go to sleep" hormone) later that night. This helps you start the day off on the right foot — before exposing yourself to a smartphone or other screen — allowing your body to release the proper hormones it needs to help you focus and be happy throughout the day.
If you're looking for a way to improve your health in 2023, consider making a goal to practice "sunlight before screen light" in January and see how you feel. When you wake up each morning, try to get outside and expose yourself to 5-10 minutes of direct sunlight (looking through a window won't trigger the same effect). Commit to doing this practice every morning for a few weeks and see if you notice a difference in your productivity, mental health and quality of sleep — you might be surprised!
This article first appeared in the January 2023 edition of the HealthPerks newsletter.