Sleep

1. Sleepwell supported · human dataAdded 19 August 2026

   Tai chi beats qigong on sleep, but not for everyone

   Traditional Chinese exercise improved sleep quality across 20 pooled randomised trials, cutting Pittsburgh Sleep Quality Index scores by 2.24 points on average, with tai chi outperforming qigong. Several groups, including college students, stroke patients and people with episodic migraine, saw no significant benefit.

   ⚠What it shows: Encouraging but uneven: results pooled from 20 trials showed better sleep in groups including older adults and people with insomnia, but no benefit for students, stroke patients or breast cancer patients. The studies disagreed with each other a lot, so the authors themselves say to read the findings cautiously.Meta-analysis · Medicine (Baltimore)

   Full breakdown →Pittsburgh Sleep Quality Index (PSQI) explained →Sleep Calculator →Effects of traditional Chinese exercise on sleep quality: A systematic review and meta-analysis of randomized controlled trials. Medicine (Baltimore) 2023
2. Sleepwell supported · human dataAdded 19 August 2026

   Resistance training tops the list of drug-free sleep fixes

   Pooling 24 randomised trials in nonelderly people, a network meta-analysis found resistance training was the most effective drug-free intervention for improving sleep quality, ahead of general physical activity, nutritional interventions and other forms of exercise.

   ⚠What it shows: A credible ranking rather than a final answer: it pools 24 trials of different drug-free sleep strategies in younger and middle-aged people and compares them indirectly, since most were never tested head to head. The abstract does not say how large the benefit was, only that lifting came out on top.Meta-analysis · PLoS One

   Full breakdown →Optimising Your Sleep Environment →Sleep Calculator →The effects of nonpharmacological sleep hygiene on sleep quality in nonelderly individuals: A systematic review and network meta-analysis of randomized controlled trials. PLoS One 2024
3. Sleepwell supported · human dataAdded 19 August 2026

   Exercise eases sleep apnoea whatever your weight

   Across 12 randomised trials of 526 people with obstructive sleep apnoea, exercise training cut the apnoea-hypopnoea index by 7.08 events per hour, reduced daytime sleepiness and improved fitness, and it worked regardless of baseline severity or body mass index.

   ⚠What it shows: Reasonably strong: results pooled from 12 trials in 526 people with sleep apnoea, all assigned at random to exercise or control, and the benefits held across severities and body sizes. The individual trials were small, and people already using CPAP consistently gained fitness but saw no extra drop in apnoea events or sleepiness.Meta-analysis · J Clin Sleep Med

   Full breakdown →VO₂max explained →VO2max Calculator →Effects of aerobic exercise and resistance training on obstructive sleep apnea: a systematic review and meta-analysis. J Clin Sleep Med 2024
4. Sleepwell supported · human dataAdded 18 August 2026

   Aerobic exercise tops the sleep table after midlife

   Across 28 randomised trials in 3,460 middle-aged and older adults, aerobic exercise ranked as the most effective exercise type for improving overall sleep quality scores, while yoga ranked best for sleep efficiency, sleep duration and daytime function.

   ⚠What it shows: A credible ranking rather than a race result: it pools 28 trials in 3,460 middle-aged and older adults, but many comparisons between exercise types are indirect, so which one wins is a probability estimate rather than a head-to-head verdict.Meta-analysis · J Clin Sleep Med

   Full breakdown →Pittsburgh Sleep Quality Index (PSQI) explained →Sleep Calculator →Effects of different types of exercise on sleep quality based on Pittsburgh Sleep Quality Index in middle-aged and older adults: a network meta-analysis. J Clin Sleep Med 2024
5. Sleeppreliminary · human dataAdded 18 August 2026

   Fasting diets leave sleep largely untouched

   Across 16 randomised trials in adults with overweight or obesity, alternate-day fasting, time-restricted eating and the 5:2 diet left overall sleep quality scores no different from ordinary dieting or a usual diet, with only slight delays in falling asleep on some measures.

   ⚠What it shows: Reassuring but thin: 16 trials pooled together, most of them small and run on different fasting schedules, so the slight delays in falling asleep could easily wash out with better data. The authors themselves call for more careful studies.Meta-analysis · Nutr Metab Cardiovasc Dis

   Full breakdown →Intermittent fasting explained →The effect of intermittent fasting on sleep in adults with overweight or obesity: a network meta-analysis of randomized controlled trials. Nutr Metab Cardiovasc Dis 2026
6. Sleepwell supported · human dataAdded 17 August 2026

   Lost sleep hits endurance hardest past the 30 minute mark

   Sleep deprivation cuts endurance performance by a moderate amount, according to pooled results from 31 studies of 478 people, and efforts lasting more than 30 minutes suffer most. One night of total sleep loss and one or more nights of partial loss compromised performance to a similar degree.

   ⚠What it shows: Consistent enough to take seriously: results pooled from 31 controlled studies with 478 healthy people all pointed the same way, though most studies had unclear risk of bias. Whether elite and professional endurance athletes are hit the same way is still unknown.Meta-analysis · Eur J Sport Sci

   Full breakdown →Optimising Your Sleep Environment →Sleep Calculator →How much does sleep deprivation impair endurance performance? A systematic review and meta-analysis. Eur J Sport Sci 2023
7. Sleeppreliminary · human dataAdded 16 August 2026

   Cannabis barely changes sleep; quitting it is what wrecks it

   Sleep-lab recordings show cannabis does not consistently alter sleep duration, latency, wake time, efficiency or sleep staging. Withdrawal from regular use, by contrast, was consistently linked to disturbed sleep: shorter total sleep, slower sleep onset and REM rebound.

   ⚠What it shows: Treat this as an early correction rather than a final verdict: 18 sleep-lab studies were reviewed and nine pooled, but many were small, doses and products varied widely, and the authors call the evidence base very limited. The withdrawal effects were the most consistent finding across studies.Meta-analysis · Sleep Med Rev

   Full breakdown →REM sleep explained →Sleep Calculator →Cannabis and sleep architecture: A systematic review and meta-analysis. Sleep Med Rev 2025
8. Sleepwell supported · human dataAdded 15 August 2026

   Melatonin improves sleep quality, but not for everyone

   A meta-analysis of 23 randomised trials found melatonin supplementation improved sleep quality scores in adults, lowering the Pittsburgh Sleep Quality Index by 1.24 points on average. Benefits were clearest in people with respiratory diseases, metabolic disorders and primary sleep disorders, but absent in those with mental health or neurodegenerative conditions.

   ⚠What it shows: Solid but with a catch: results pooled from 23 trials, yet the studies disagreed with each other substantially and nearly all participants had an existing illness, so the benefit may not transfer to a healthy person with occasional bad nights. The average improvement on the sleep questionnaire was modest.Meta-analysis · J Neurol

   Full breakdown →Melatonin explained →Sleep Calculator →Effect of melatonin supplementation on sleep quality: a systematic review and meta-analysis of randomized controlled trials. J Neurol 2022
9. Sleepwell supported · human dataAdded 15 August 2026

   Prediabetes comes with nearly triple the odds of sleep apnoea

   Adults with prediabetes had 2.78 times the odds of obstructive sleep apnoea compared with people with normal blood sugar, in pooled data from eight studies covering 18,040 adults. The link was stronger in younger groups, reaching 3.44 times the odds where average age was under 55.

   ⚠What it shows: A consistent link but not proof of cause: all eight studies measured people at a single moment in time, so nobody knows whether disturbed sleep drives the blood sugar problem, the reverse, or whether something else drives both. Pooled from 18,040 adults, though the studies disagreed a fair amount on the size of the link.Meta-analysis · Front Endocrinol (Lausanne)

   Full breakdown →Insulin sensitivity explained →Metabolic Fitness Index →The association between prediabetes and obstructive sleep apnea syndrome: a meta-analysis. Front Endocrinol (Lausanne) 2026
10. Sleepwell supported · human dataAdded 15 August 2026

    Fix your sleep and your mood follows, 65 trials suggest

    A pooled analysis of 65 randomised trials found that interventions which improved sleep quality also produced medium-sized improvements in mental health, including depression and anxiety. The bigger the improvement in sleep, the bigger the mental health benefit.

    ⚠What it shows: About as strong as sleep evidence gets: results pooled from 65 trials in 8608 people, all randomly assigned. The trials used many different ways of improving sleep, and how sleep works on the mind is still not explained.Meta-analysis · Sleep Med Rev

    Full breakdown →Optimising Your Sleep Environment →Sleep Calculator →Improving sleep quality leads to better mental health: A meta-analysis of randomised controlled trials. Sleep Med Rev 2021
11. Sleepwell supported · human dataAdded 15 August 2026

    Lifting weights beats cardio for sleep in older insomniacs

    In older adults with insomnia, muscle-strengthening exercise improved sleep quality more than aerobic or combined exercise, lowering the global sleep quality index by 5.75 points across a network analysis of 25 trials.

    ⚠What it shows: A credible ranking but not the final word: results pooled from 25 trials in 2170 older adults with insomnia, and the trials often disagreed with each other sharply. Many of the comparisons between exercise types are indirect rather than head to head.Meta-analysis · Fam Med Community Health

    Full breakdown →Pittsburgh Sleep Quality Index (PSQI) explained →Sleep Calculator →Impact of different types of physical exercise on sleep quality in older population with insomnia: a systematic review and network meta-analysis of randomised controlled trials. Fam Med Community Health 2025
12. Sleepwell supported · human dataAdded 14 August 2026

    Three cardio sessions a week reshape broken sleep

    Pooled results from 18 trials in 1214 adults with sleep disorders found exercise improved sleep efficiency, cut time awake after falling asleep and extended deep slow-wave sleep. Moderate-intensity aerobic exercise done 3 times a week for 45-60 minutes over 8-12 weeks ranked best for efficiency and night waking, while training 4 or more times a week did more for deep sleep.

    ⚠What it shows: Credible for the overall effect: results pooled from 18 trials in 1214 adults with diagnosed sleep disorders. The ranking of which exercise style wins rests on indirect comparisons between studies that differed from each other, so treat the 'best modality' verdict loosely.Meta-analysis · Sleep Med

    Full breakdown →Slow-wave sleep explained →Sleep Calculator →Comparative efficacy of exercise modalities on sleep architecture in adults with sleep disorders: a systematic review and network meta-analysis of randomized controlled trials. Sleep Med 2025
13. Sleepwell supported · human dataAdded 14 August 2026

    Fish oil pills did nothing for adult sleep in pooled trials

    Pooled evidence from 20 studies found omega-3 supplementation had no effect on adults' total sleep duration, sleep latency, sleep efficiency, sleep quality or insomnia severity. Benefits appeared only in infants' sleep organisation and in children with clinical-level sleep problems.

    ⚠What it shows: About as clear as the current evidence gets: results pooled from 12 trials and 8 studies that followed people over time found nothing for adult sleep on any measure tested. The included studies varied in who they tested and how, and the authors still want more robust trials before calling it settled.Meta-analysis · Nutr Rev

    Full breakdown →Omega-3 (fish oil) guide →Sleep Calculator →Omega-3 long-chain polyunsaturated fatty acid and sleep: a systematic review and meta-analysis of randomized controlled trials and longitudinal studies. Nutr Rev 2021
14. Sleepwell supported · human dataAdded 14 August 2026

    Insomnia therapy works from your phone, and the benefit lasts months

    Cognitive behavioural therapy for insomnia delivered through mobile apps reduced insomnia symptoms and improved sleep quality in a meta-analysis of 16 trials with 2146 adults, with benefits lasting up to six months. Programmes with all five CBT-I components, running six weeks or longer and delivered by healthcare professionals, showed the strongest results.

    ⚠What it shows: Solid evidence: results pooled from 16 trials with 2146 adults all pointed the same way, and the benefit held at follow-up. The trials only tracked people for up to six months, so nobody yet knows whether the improvement lasts beyond that.Meta-analysis · J Clin Nurs

    Full breakdown →Pittsburgh Sleep Quality Index (PSQI) explained →Sleep Calculator →Effectiveness of Mobile Health-Delivered Cognitive Behavioural Therapy for Insomnia in Adults: A Systematic Review and Meta-Analysis of Randomised Controlled Trials. J Clin Nurs 2026
15. Sleepwell supported · human dataAdded 13 August 2026

    A quarter of Chilean adults flag as high risk for sleep apnoea

    Pooled data from 15 Chilean studies covering 13,157 people put 25% of adults at moderate-to-high risk of obstructive sleep apnoea, based mostly on screening questionnaires rather than objective sleep tests.

    ⚠What it shows: Solid as a screening estimate, thin as a diagnosis: results pooled from 15 studies of 13,157 people relied mostly on questionnaires, with only three using overnight breathing recordings. The studies also disagreed with each other strongly, so the true figure could sit anywhere between roughly 16% and 34%.Meta-analysis · Rev Med Chil

    Full breakdown →Epidemiology of Obstructive Sleep Apnea in Chile: A Systematic Review and Meta-Analysis. Rev Med Chil 2026
16. Sleeppreliminary · human dataAdded 13 August 2026

    Scraping therapy eased insomnia scores, but safety went unrecorded

    Pooled results from 22 randomised trials in 1816 people suggest holographic scraping, a traditional Chinese skin-scraping therapy, reduced insomnia, anxiety and depression scores; only 2 trials reported on adverse effects, so its safety remains unclear.

    ⚠What it shows: Interesting but far from settled: results pooled from 22 trials in 1816 people looked good on symptom scores, yet the picture for measured sleep quality was mixed. Only 2 of the trials reported side effects, so safety is simply unknown.Meta-analysis · Medicine (Baltimore)

    Full breakdown →Pittsburgh Sleep Quality Index (PSQI) explained →Sleep Calculator →Efficacy and safety of holographic scraping in insomnia: A systematic review and meta-analysis of randomized controlled trials. Medicine (Baltimore) 2026
17. Sleeppreliminary · human dataAdded 11 August 2026

    Meditation improved sleep in older adults with mild memory decline

    Meditation-based programmes lasting 4 to 12 weeks improved self-reported sleep quality in adults aged 55 and over with mild cognitive impairment, with a moderate to large pooled effect, and were also linked to less anxiety, stress and depression.

    ⚠What it shows: Promising but not settled: results pooled from seven small studies in 434 older adults, some without random assignment, and the studies disagreed with each other on how big the benefit is. Sleep was mostly self-reported rather than measured objectively.Review · Geriatr Nurs

    Full breakdown →Breathwork for Recovery and Stress →Sleep Calculator →The effects of meditation-based interventions on sleep quality among adults aged ≥ 55 with mild cognitive impairment: A systematic review and meta-analysis. Geriatr Nurs 2026
18. Sleeppreliminary · human dataAdded 11 August 2026

    Cannabinoids added about half an hour to total sleep time

    Pooled results from 10 randomised trials in 2134 adults with insomnia or poor sleep found cannabinoids reduced insomnia severity and improved sleep quality scores, increased total sleep time by 33.99 min, lifted sleep efficiency by 4.31% and modestly cut time to fall asleep by 12.0 min. Side effects, mostly mild dizziness and dry mouth, were roughly four times more frequent than with comparators, with no serious harms recorded.

    ⚠What it shows: Encouraging but not the last word: results pooled from 10 randomised trials in 2134 adults, comparing cannabinoids against placebo or melatonin. The trials were mostly short, so the right dose and whether the benefit lasts are both unresolved, and mild dizziness and dry mouth were clearly more common.Review · Sleep Med

    Full breakdown →Pittsburgh Sleep Quality Index (PSQI) explained →Sleep Calculator →Efficacy of cannabinoids for insomnia and sleep disturbance: A systematic review and meta-analysis of randomized controlled trials. Sleep Med 2026
19. Sleepwell supported · human dataAdded 10 August 2026

    Exercise eased menopausal insomnia most where sleep was worst

    Exercise programmes significantly reduced insomnia severity and eased sleep problems in menopausal women in a meta-analysis of randomised trials, with the clearest effects in women who already had sleep disorders. Overall sleep quality scores did not improve significantly.

    ⚠What it shows: Encouraging but uneven: results pooled from ten trials where women were assigned at random showed less insomnia but no clear change in overall sleep quality scores, and the underlying studies carried a moderate risk of bias. The review also could not tell which type or length of exercise works best.Systematic review · Front Med (Lausanne)

    Full breakdown →Optimising Your Sleep Environment →Sleep Calculator →The effect of exercise intervention on improving sleep in menopausal women: a systematic review and meta-analysis. Front Med (Lausanne) 2023
20. Sleepwell supported · human dataAdded 10 August 2026

    Aerobic exercise outdoes traditional Chinese exercise for student sleep

    Pooled results from 21 randomised trials in 1252 university students with sleep problems found both traditional Chinese exercises and general aerobic exercise improved sleep, with aerobic exercise the more effective of the two. Effects were largest with sessions of 40 to 60 minutes, done 3 to 5 times a week.

    ⚠What it shows: Strong for students, unknown beyond them: results pooled from 21 trials covering 1252 university students, all with existing sleep problems. The trials disagreed with each other enough that the best session length and frequency should be read as a rough guide, not a prescription.Meta-analysis · Medicine (Baltimore)

    Full breakdown →Sleep Calculator →Comparing the efficacy of traditional Chinese exercises and general aerobic exercises in university students with sleep disorders: A systematic review and meta-analysis. Medicine (Baltimore) 2024
21. Sleeppreliminary · human dataAdded 9 August 2026

    Phone addiction tracks with worse sleep in young adults

    A meta-analysis pooling 63 observational studies found a moderate correlation (r=0.38) between smartphone addiction and poor sleep quality in adults aged 18 to 25, alongside later sleep onset, shorter sleep and more daytime dysfunction.

    ⚠What it shows: Consistent but correlational: nearly all the underlying studies were cross-sectional and self-reported, so poor sleepers may simply reach for their phones more, not the reverse. The pooled link was moderate and results varied enormously between studies.Review · Int J Adolesc Med Health

    Full breakdown →Optimising Your Sleep Environment →Sleep Calculator →Smartphone addiction and sleep disruption among young adults (18-25 years): a systematic review and meta-analysis. Int J Adolesc Med Health 2026
22. Sleepwell supported · human dataAdded 9 August 2026

    Late-night hard training doesn't ruin sleep after all

    A meta-analysis of 15 trials found that high-intensity exercise finishing 2 to 4 hours before bedtime did not disrupt nighttime sleep in healthy adults; the only significant change was a small 2.34% reduction in REM sleep.

    ⚠What it shows: A trustworthy pooled result built from small studies: 15 trials totalling just 194 healthy good sleepers aged 18 to 50. It says nothing about people who already sleep badly, or about sessions finishing very close to lights out.Meta-analysis · Sleep Med Rev

    Full breakdown →HIIT explained →Sleep Calculator →The effects of evening high-intensity exercise on sleep in healthy adults: A systematic review and meta-analysis. Sleep Med Rev 2021
23. Sleepwell supported · human dataAdded 9 August 2026

    The weights room doubles as a sleep aid

    A systematic review of 13 randomised trials found that regular resistance training improves all aspects of sleep, with the greatest benefit for sleep quality, and also improves anxiety and depression.

    ⚠What it shows: A credible review of a thin evidence base: just 13 trials, and the sleep benefit shrank when lifting was combined with aerobic work rather than done on its own. What a single session does to that night's sleep remains poorly studied and inconsistent.Systematic review · Sleep Med Rev

    Full breakdown →Optimising Your Sleep Environment →Sleep Calculator →The effect of resistance exercise on sleep: A systematic review of randomized controlled trials. Sleep Med Rev 2018
24. Sleeppreliminary · human dataAdded 8 August 2026

    Ultrasound sleep patch lengthened REM in a 28-participant study

    A skin-attached patch that pairs focused ultrasound with overnight brainwave recording, aimed at the subthalamic nucleus, increased REM duration by 4.6% and reduced REM latency by 24% in a 28-participant study.

    ⚠What it shows: One 28-participant registered study of a prototype device, reported by the engineering team that developed it and has filed a patent; the abstract gives no daytime outcomes, no safety data and no independent replication.Clinical trial · Nat Commun

    Full breakdown →REM sleep explained →Sleep Calculator →Skin-attached bioadhesive patch enabling ultrasound deep brain stimulation and real-time electrophysiological monitoring for REM sleep enhancement. Nat Commun 2026

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