Circadian Rhythms & Internal Body Clocks, & Why You Can’t Sleep

Now that many of us are safely on the other side of the time change, we can enjoy the extra daylight hours a little more. And hopefully by now our circadian rhythms have also gotten with the program that our sleep-wake times have been shifted by an hour. 

Circadian Rhythms

Consider circadian rhythm to be your natural biological clock. Based out of the hypothalamus of the brain, it relies on light being sensed by the eyes to know what time it is. It can then dictate the timing of our sleep-wake cycle and other metabolic processes such as appetite, ovulation, and digestive fire (preparing us to eat at set times every day). 

When sunlight comes in through the eyes, the brain picks up the cue that it’s daylight now. (And for those of us that have a premature wakeup call, say around 2-4 am, I feel for you! This is a different issue, but also cortisol-driven. More about this another time.) This light stimulation releases a cortisol surge to pull us from sleep and get us bouncing out of bed. Time to be active! Later, as the sun sets and darkness takes over, this internal clock signals the body that it is time to sleep by releasing melatonin, our sleepy hormone.

The light color (wavelength) is critical to this biological process. Blue light signals cortisol. White light contains blue light. Daylight is bright white light, rich with blue light. Conversely, red/orange, opposite blue on the color theory wheel, supports melatonin production. Dusk is red/orange light. 

When talking about circadian rhythm and its dictation by the sun, my clients often hear me regaling them with tales of our ancient ancestors, who relied on sunlight and firelight to set the course of the day. In the morning they were woken by the white/blue light put out by the sun. As the sun set, the sky lit up with beautiful hues of pinks and oranges, and our ancestors wound down from their action-packed day of hunting and gathering. They may have stayed up a little later by the orangey glow of a campfire, and once it burned out, it was too dark to safely be out and about, and  so everyone went to sleep. The natural colors from their light sources regulated their body clocks (and dictated their activities). 

In today’s modern, electricity-dependent world, we have many opportunities for circadian dysregulation. Anticipated stress of the upcoming day and overall high stress levels may send us a jolting wake-up call that’s earlier than we would desire to be awake. We spend much of our waking hours indoors, in artificially lit rooms or in rooms filtered by window panes. Our bedrooms may not be so dark due to light pollution or a well-intentioned nightlight or the glow of electronic devices that never shut off (smoke detectors, power buttons, alarm clocks, thermostats…), which can make it harder to get into a deeper sleep state. We also use electronics and artificial indoor lighting to extend our waking hours, which can impinge on quality and quantity of sleep. All of these factors and more can upset our internal clocks, causing our natural body rhythms to get out of sync. 

Resetting Your Internal Body Clock 

To maximize circadian rhythm and obtain the deepest sleep possible, consider a few tips: 

1. Get sunlight exposure first thing in the morning: This natural white/blue light cues your body as to the time of day and will help to reset an “off” circadian rhythm/biological clock. If it’s dark when you first wake up, use a sunlight lamp or light box (we suggest Verilux) for about 20-30 minutes to help cue daytime. 
2. Keep things dark 1-2 hours before bed: When the sun starts to set, start darkening the lights in your house. This will cue your brain that it’s getting close to sleep time and trigger melatonin secretion. During this evening window, consider transitioning from overhead to table and floor lamps, using dimmer switches or candles, maybe replacing some lightbulbs with orange tinted bulbs (found on Amazon), and avoiding using screens that cannot be adjusted to have a blue-light filter (we suggest F.lux software for computers, and NightShift on the warmest setting for iPhones and iPads).
3. Enhance your sleep environment: Make your room as dark as possible at night. This may mean room-darkening shades or wearing a fashionable sleep mask. Also consider drowning out loud noises with a low white-noise machine (choose a fan over a digital sound machine) or using ear plugs to keep from startling awake from loud noises overnight. 
4. Choose calm: Your biological clock is connected to your stress response. If you’re choosing high-stress activities at night (budgeting finances, working, tough conversations, thrillers/horrors/action packed shows, etc.), your body will send out stress hormones that will impair and even override melatonin secretion. After all, your body thinks it’s not safe to go to sleep at that time. Choose calming rituals like reading a book, taking an Epsom bath, stretching, or meditation. This will also help to keep from a huge cortisol surge in the morning, which will jar you awake at the wrong time. 
5. Keep your sleep schedule consistent! Go to sleep and wake up at the same time nearly every single day – yes, even on the weekends (I know, I know). This will help keep your body’s internal clock balanced and prevent sleep disorders. After all, if you’re getting enough sleep regularly, you won’t have a need to sleep in and catch up on sleep.