Sleep Research Library
Every ranking is backed by published research. Here are the studies and our living meta-summary.
Quantifying the population-level impact of insomnia on dementia among older adults in the United States
Insomnia may account for ~13% of all dementia cases in US older adults — an estimated 449,069 preventable cases in 2022. Treating insomnia early could be one of the most impactful dementia-prevention strategies available.
Multiple Health Outcomes of Daytime Napping: A Comprehensive Umbrella Review
Short naps (20–30 min) improve athletic performance by SMD=0.99 and cognition by SMD=0.69 with reduced mortality risk. Naps over 60 min raise coronary heart disease risk by 30%, diabetes risk by 20%, and obesity risk by 20%.
Magnesium Bisglycinate Supplementation in Healthy Adults Reporting Poor Sleep
Magnesium bisglycinate produced a modest but statistically significant reduction in insomnia severity after 4 weeks.
Impact of white noise on sleep quality across age groups
White noise improves sleep best as a masking tool when environmental noise is the dominant disruptor.
Polysomnographic Evidence of Enhanced Sleep Quality with Adaptive Thermal Regulation
Adaptive mattress temperature improved total sleep time, sleep efficiency, and REM timing versus control conditions.
Validity and reliability of the Oura Ring Generation 3 with PSG
Oura Gen 3 showed good agreement for global sleep metrics, but wake detection and stage precision still fall short of clinical PSG.
Interventions to reduce short-wavelength ("blue") light exposure at night and their effects on sleep
Reducing blue light at night appears to help sleep efficiency and subjective sleep quality, but the evidence is mixed and highly context-dependent.
The effect of acute sleep deprivation on skeletal muscle protein synthesis and the hormonal environment
One night of total sleep deprivation reduced postprandial skeletal muscle protein fractional synthesis rate (FSR) by 18% (0.072 → 0.059%·h⁻¹, p=.040), dropped plasma testosterone by 24% (p=.029), and elevated cortisol by 21% (p=.030) — creating a fully catabolic hormonal environment from a single missed night. Sleep is the primary anabolic window; one bad night starts undoing your gains.
Periocular skin warming promotes body heat loss and sleep onset
Periocular warming accelerated sleep onset and increased stage 2 sleep by helping the body dump heat more efficiently before sleep.
A randomized controlled study of weighted chain blankets for insomnia in psychiatric disorders
Weighted blankets improved insomnia severity and several daytime symptoms without serious adverse events.
Effect of different mattress designs on promoting sleep quality, pain reduction, and spinal alignment
Across controlled trials, medium-firm and custom-inflated mattresses produced the most consistent gains in comfort and pain reduction.
Does poor sleep quality affect skin ageing?
Poor sleepers showed 30% less skin barrier recovery after tape stripping, significantly higher intrinsic aging scores on SCINEXA™, worse UV-induced erythema recovery, and lower self-perceived attractiveness. Good sleep (7–9h) is the most accessible and cost-effective anti-aging intervention available.
Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed
A substantial caffeine dose taken even 6 hours before bedtime significantly disrupted sleep relative to placebo.
Effect of 1 Week of Sleep Restriction on Testosterone Levels in Young Healthy Men
One week of sleeping 5 hours per night reduced daytime testosterone by 10–15% in young healthy men — an effect comparable to 10–15 years of normal aging. Afternoon testosterone fell from 17.9 to 15.5 nmol/L (p=0.02). Vigor scores dropped 32% across the restriction week.
The Effects of Sleep Extension on the Athletic Performance of Collegiate Basketball Players
Sleep extension to a minimum of 10 hours in bed increased total nightly sleep by 110.9 min and produced a 9% improvement in free throw accuracy, 9.2% improvement in 3-point shooting, faster sprint times (16.2 → 15.5 sec), and significantly quicker reaction times. Every performance metric improved with p < 0.001.
Effects of artificial dawn on subjective ratings of sleep inertia
Artificial dawn reduced complaints of sleep inertia even when melatonin timing did not clearly shift.
Overnight therapy? The role of sleep in emotional brain processing
Sleep loss reliably amplifies emotional reactivity and weakens top-down regulation, making mental health a core sleep outcome rather than a side effect.
Effect of firmness of mattress on chronic non-specific low-back pain
Medium-firm mattresses outperformed firm mattresses for pain in bed, pain on rising, and disability after 90 days.