Getting adequate, restful sleep is crucial for our health and wellbeing. When we don’t get enough quality sleep, it can negatively impact our physical and mental health in many ways. One way to promote better sleep is through using color light therapy. Research shows that exposure to certain colors of light in the evening and at nighttime can help relax the body and mind, making it easier to fall asleep and get more restorative sleep.
Blue Light and Sleep
Blue wavelength light is one of the most alerting colors for the brain. Exposure to blue light during the day from sunlight helps regulate our circadian rhythms and keeps us awake and alert. However, exposure to blue light at night from screens and devices can disrupt our natural sleep cycles by suppressing melatonin production. Melatonin is our sleep hormone that helps initiate sleep. Studies show that using blue light blocking glasses in the evening, avoiding screens before bedtime, and using devices on night shift mode can help reduce blue light exposure for better sleep quality.
| Blue Light Source | Tips to Limit Exposure |
|---|---|
| Screens (phones, tablets, TV, computers) | Avoid use 1-2 hrs before bed, use night shift mode, use blue light blocking glasses |
| Overhead and ambient lighting | Replace with warm white bulbs, use dimmers |
Warm White and Amber Lighting
Warm white light with more red/orange wavelengths is less activating for the brain compared to cooler blue light. Using amber or warm white colored bulbs in table lamps and overhead lighting in the evening can help cue the body that it’s time to wind down and prepare for sleep. Look for bulbs that are 2700-3000K color temperature which give off a soft warm glow. Smart bulbs like Philips Hue can be programmed to automatically dim and change to amber lighting at bedtime too.
Green Light
Green light may also have benefits for sleep by helping increase melatonin levels. In one study, people exposed to green light before bedtime had significantly higher melatonin levels at night compared to blue or violet light. More research is still needed, but using green color bulbs or wearing green tinted glasses in the evening may support better sleep in the future.
Red Light
Red light is considered the most “sleep-friendly” color of light. Red light has the longest wavelengths while blue light has the shortest, making red appear dimmer and less visually sharp compared to blue. Using red light in the evening has less impact on suppressing melatonin like blue light does. Red light also does not shift circadian rhythms like other colors potentially can. Studies find that exposure to red light before bed can lead to faster sleep onset and increased amounts of deep, restorative NREM sleep.
| Red Light Benefits for Sleep | Tips for Use |
|---|---|
| Less melatonin suppression | Use red bulbs in bedside lamps |
| Faster sleep onset | Wear red tinted glasses before bed |
| Increased deep NREM sleep | Use red night lights in hallways and bathrooms |
Lavender and Purple Light
Lavender and purple represent a sweet spot between wavelengths that are overly alerting but not too soporific. Studies show lavender and purple lights can ease anxiety, lower heart rate and blood pressure, and induce feelings of relaxation. Natural lavender oil is also used to promote sleep due to its calming properties. Lavender/purple light may act similarly to create a relaxing pre-sleep environment, but more research is still needed on effects on sleep architecture and quality.
Pink Light
Some research indicates that pink light may also have relaxing, sleep-promoting effects. One study had participants spend 30 minutes exposed to blue, green or pink light in the evening. Participants exposed to pink light had higher melatonin levels and reported feeling sleepier compared to blue light. Using a pink hue lightbulb or wearing pink-tinted glasses in the evening could potentially signal rest and relaxation time before bed.
Candlelight
The warm flicker of candlelight sets a calming mood and ambiance. Studies show that exposure to candlelight and firelight improves mood, decreases anxiety and stress hormones, and increases social bonding hormones like oxytocin. Historically before electricity, humans spent evenings exposed to firelight. The warm glow is likely imprinted as a natural cue for relaxation time before sleep. Light from candles, oil lamps, or simulated fireplaces can help dim lighting at night, supporting rest and circadian rhythms.
Complete Darkness
While certain colors like red and pink can promote sleepiness, the best sleep environment is as close to complete darkness as possible. Any light contamination in the bedroom can disrupt sleep. Even small amounts of light penetration through curtains or under doorways is registered by photoreceptors that relay signals to the brain that it’s daytime. Studies show that using blackout curtains, eye masks, or taping over LED lights leads to faster sleep onset, increased deep sleep time, and improved mood.
Conclusion
The color and type of light we are exposed to in the evening greatly impacts sleep quality and circadian rhythms. Cool blue light and bright white light can create alertness. Warm white, amber, red, pink, lavender and candlelight can help cue relaxation and sleepiness. But ultimately, completely blocking out light is ideal for optimizing the sleep environment. Adjust lighting and remove light contamination from the bedroom for improved rest at night.