Featured Research

Complete Research Citations
These studies support the data and insights referenced in our article “Your Bedroom Is Medicine: Designing a Space That Actually Heals.”

Economic Costs & Sleep Statistics

1. RAND Corporation Economic Study (2016)
Hafner M, Stepanek M, Taylor J, Troxel WM, Van Stolk C. Why Sleep Matters—The Economic Costs of Insufficient Sleep: A Cross-Country Comparative Analysis. RAND Corporation, RR-1791-VH, 2016.
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Supports: “$411 billion annually,” “2.28% of GDP,” “1.2 million working days lost”

2. CDC Sleep Duration Study (2016)
Liu Y, Wheaton AG, Chapman DP, Cunningham TJ, Lu H, Croft JB. Prevalence of Healthy Sleep Duration among Adults—United States, 2014. MMWR Morb Mortal Wkly Rep. 2016; 65(6): 137-141.
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Supports: “More than one in three Americans gets fewer than seven hours of sleep per night”

3. CDC Chronic Disease Indicators (2023)
Centers for Disease Control and Prevention. Sleep Statistics. CDC Chronic Disease Indicators. Updated 2025.
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Supports: High school student sleep statistics, insufficient sleep prevalence

Light Exposure & Circadian Rhythm

4. Bedroom Light Exposure Study — 81-Minute Delay (2024)
Xu YX, Shen YT, Li J, et al. Exposure to real-ambient bedroom light at night delayed circadian rhythm in healthy Chinese young adults: A cross-sectional study. Ecotoxicol Environ Saf. 2024; 280: 116590.
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Supports: “Higher nighttime light levels were associated with an 81-minute delay in the body’s natural sleep signal”

5. TV/Light On During Sleep Study (2019)
Park YM, White AJ, Jackson CL, Weinberg CR, Sandler DP. Association of Exposure to Artificial Light at Night While Sleeping With Risk of Obesity in Women. JAMA Intern Med. 2019; 179(8): 1061–1071.
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Supports: “Sleeping with a TV or lights on is associated with significantly poorer sleep”

6. Sister Study on Indoor Light at Night (2024)
James P, Cai J, Bliwise DL, et al. Exposure to indoor light at night in relation to multiple dimensions of sleep health: findings from the Sister Study. Sleep. 2024; 47(2): zsad100.
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Supports: Multiple dimensions of poor sleep with TV or lights on

7. Smartphone Use Before Bed Study (2014)
Chang AM, Aeschbach D, Duffy JF, Czeisler CA. Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. Proc Natl Acad Sci USA. 2015; 112(4): 1232-1237.
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Supports: “Using smartphones in bed before sleep predicted circadian phase delays and reduced sleep quality”

Bedroom Temperature & Sleep

8. Temperature and Sleep Efficiency Study (2020)
Kang M, Yan Y, Zhang H, et al. Higher Bedroom Temperature Associated With Poorer Sleep: Data From Over 3.75 Million Nights. Sleep. 2020; 43(Suppl 1): A464.
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Supports: “For each 1°F increase in bedroom temperature, sleep efficiency decreased by ~0.06%”

9. Optimal Temperature for Older Adults Study (2023)
Baniassadi A, Albin N, Yamazaki F, et al. Nighttime ambient temperature and sleep in community-dwelling older adults. Sci Adv. 2023; 9(33): eadg0492.
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Supports: “Sleep was most efficient between 68-75°F (20-24°C), declining outside this range”

Air Quality ( CO₂ & PM2.5 )

10. Bedroom CO₂ and Ventilation Study (2015)
Strøm-Tejsen P, Zukowska D, Wargocki P, Wyon DP. The effects of bedroom air quality on sleep and next-day performance. Indoor Air. 2016; 26(5): 679-686.
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Supports: “Better ventilation and lower CO₂ levels (~835 ppm vs 2395 ppm) improved sleep quality and next-day performance”

11. PM2.5, CO₂, Temperature & Sleep Study (2023)
Basner M, Smith MG, Jones CW, et al. Associations of bedroom PM2.5, CO₂, temperature, humidity, and noise with sleep: An observational actigraphy study. Sleep Health. 2023; 9(3): 253-265.
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Supports: “For every increase in PM2.5, temperature, and CO₂, sleep efficiency decreased significantly — with air quality showing the strongest effect”

General Sleep Science

12. Systematic Review of Light on Circadian Rhythm (2018)
Hänninen O, Kirjavainen J, Yli-Tuomi T, Haverinen-Shaughnessy U. Systematic review of light exposure impact on human circadian rhythm. Chronobiol Int. 2018; 35(10): 1401-1420.
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Supports: Overview of circadian rhythm science and light’s physiological effects