# Sleep Better PWA — Scientific Literature & Evidence Base **Languages:** English + Brazilian Portuguese **Purpose:** This document explains the scientific and practical foundation behind the Sleep Better PWA checklist and routines. It is not medical advice. It is a project knowledge base for healthy sleep hygiene, behavioral design, and safe implementation choices. --- ## 1. Executive summary / Resumo executivo ### English The Sleep Better PWA is based primarily on **sleep hygiene**, **circadian rhythm regulation**, and **behavioral habit design**. The strongest foundations are: consistent sleep/wake timing, morning daylight, reduced evening light and stimulation, caffeine cutoff, avoiding heavy meals and alcohol near bedtime, a cool/dark/quiet bedroom, and a repeatable wind-down routine. Some items are **optional or experimental**: mouth taping, sleep supplements, and optimization based on wearable “sleep scores.” These can be useful for some people, but they should not be treated as core sleep treatment. The app therefore prioritizes low-risk behaviors and labels riskier or weaker-evidence practices clearly. ### Português do Brasil O Sleep Better PWA é baseado principalmente em **higiene do sono**, **regulação do ritmo circadiano** e **design comportamental de hábitos**. Os pilares mais fortes são: horário regular para dormir/acordar, luz natural pela manhã, redução de luz e estímulos à noite, corte de cafeína, evitar refeições pesadas e álcool perto da hora de dormir, quarto fresco/escuro/silencioso e uma rotina repetível de desaceleração. Alguns itens são **opcionais ou experimentais**: tapar a boca para dormir, suplementos e otimização por “sleep score” de wearables. Eles podem ajudar algumas pessoas, mas não devem ser tratados como tratamento principal. Por isso, o app prioriza comportamentos de baixo risco e sinaliza claramente práticas com evidência mais fraca ou maior cautela. --- ## 2. Evidence grading used in the app / Classificação de evidência usada no app | Level | English meaning | Significado em PT-BR | App treatment | |---|---|---|---| | **Strong** | Supported by public health guidance, sleep medicine guidelines, or repeated evidence | Apoiado por diretrizes de saúde pública, medicina do sono ou evidência repetida | Core checklist item | | **Moderate** | Plausible and supported by studies, but individual response varies | Plausível e apoiado por estudos, mas varia por pessoa | Adjustable recommendation | | **Weak / optional** | Limited evidence, trend-based, or useful only in specific cases | Evidência limitada, tendência ou útil só em casos específicos | Optional item with warning | | **Caution** | Potential risk or should involve medical guidance | Pode trazer risco ou exigir orientação profissional | Safety note, not a default habit | --- ## 3. Core principles / Princípios centrais ### 3.1 Regular sleep-wake rhythm / Regularidade do horário de sono **English:** Keeping a stable bedtime and wake time helps entrain the circadian system. Public health guidance from the CDC recommends going to bed and waking up at the same time every day. Harvard Sleep Medicine also emphasizes maintaining a regular sleep-wake schedule as a foundational sleep habit. **Português:** Manter horário relativamente estável para dormir e acordar ajuda a regular o sistema circadiano. O CDC recomenda dormir e acordar no mesmo horário todos os dias. A área de Medicina do Sono de Harvard também coloca a regularidade como hábito fundamental. **App implementation:** - User sets target bedtime and wake time. - App calculates daily sleep window. - Checklist rewards consistency rather than perfection. **Evidence level:** Strong **Sources:** - CDC — About Sleep: https://www.cdc.gov/sleep/about/index.html - Harvard Division of Sleep Medicine — Adopt Good Sleep Habits: https://sleep.hms.harvard.edu/education-training/public-education/sleep-and-health-education-program/sleep-health-education-93 --- ### 3.2 Morning daylight and evening darkness / Luz pela manhã e escuridão à noite **English:** Light is one of the strongest signals for the circadian clock. Morning light tends to advance and stabilize the biological clock, while evening and night light can delay circadian timing. Blue-rich and bright white light can suppress melatonin and shift circadian rhythms, especially during sensitive evening periods. **Português:** A luz é um dos sinais mais fortes para o relógio circadiano. A luz pela manhã tende a adiantar e estabilizar o relógio biológico, enquanto luz à noite pode atrasar o ritmo circadiano. Luz branca intensa e rica em azul pode suprimir a melatonina e deslocar o ciclo circadiano, especialmente à noite. **App implementation:** - Morning daylight checklist item. - Evening dimming mode. - Warm-color overlay simulation inside the app. - “Dim lights” reminder before bedtime. **Evidence level:** Strong to moderate **Important limitation:** A PWA cannot directly change the phone’s system-wide brightness, Night Shift, Night Light, or display color temperature. It can only adjust the app interface or guide the user to change device settings manually. **Sources:** - Blume et al., 2019 — Effects of light on human circadian rhythms, sleep and mood: https://pmc.ncbi.nlm.nih.gov/articles/PMC6751071/ - CDC/NIOSH — The Color of the Light Affects Circadian Rhythms: https://www.cdc.gov/niosh/work-hour-training-for-nurses/longhours/mod2/20.html - AASM Sleep Education — Healthy Sleep Habits: https://sleepeducation.org/healthy-sleep/healthy-sleep-habits/ --- ### 3.3 Caffeine cutoff / Corte de cafeína **English:** Caffeine promotes wakefulness by blocking adenosine. Its half-life varies widely between individuals, and it can affect sleep even when consumed hours before bed. A systematic review found caffeine reduced total sleep time by about 45 minutes, reduced sleep efficiency, increased sleep latency, and reduced deep sleep. Sleep Foundation recommends avoiding caffeine at least 8 hours before bedtime. **Português:** A cafeína aumenta o estado de alerta ao bloquear a adenosina. Sua meia-vida varia bastante entre pessoas e pode afetar o sono mesmo horas antes de dormir. Uma revisão sistemática encontrou redução de aproximadamente 45 minutos no tempo total de sono, redução da eficiência do sono, aumento da latência para dormir e redução de sono profundo. A Sleep Foundation recomenda evitar cafeína pelo menos 8 horas antes de dormir. **App implementation:** - User enters target bedtime. - App calculates a suggested caffeine cutoff time: bedtime minus 8 hours. - Users can adjust cutoff based on sensitivity. **Evidence level:** Strong **Sources:** - Sleep Foundation — Caffeine and Sleep Problems: https://www.sleepfoundation.org/nutrition/caffeine-and-sleep - Gardiner et al., 2023 — The effect of caffeine on subsequent sleep: https://www.sciencedirect.com/science/article/pii/S1087079223000205 - CDC — About Sleep: https://www.cdc.gov/sleep/about/index.html --- ### 3.4 Meals, alcohol, and digestion / Refeições, álcool e digestão **English:** Large meals close to bedtime can interfere with sleep and may worsen reflux or digestive discomfort. A practical target is finishing large meals around 3 hours before bed. A rigid 5-hour rule may help some people but is not required for everyone. Alcohol may make people feel sleepy initially, but it can fragment sleep, worsen snoring, and reduce REM sleep quality. **Português:** Refeições grandes perto da hora de dormir podem prejudicar o sono e piorar refluxo ou desconforto digestivo. Uma meta prática é terminar refeições maiores cerca de 3 horas antes de dormir. A regra rígida de 5 horas pode ajudar algumas pessoas, mas não é obrigatória. O álcool pode dar sonolência no início, mas tende a fragmentar o sono, piorar ronco e reduzir a qualidade do sono REM. **App implementation:** - Last big meal target: bedtime minus 3 hours by default. - Optional advanced setting: 3–5 hour range. - Alcohol warning included in evening checklist. **Evidence level:** Moderate to strong **Sources:** - Harvard Health — Sleep hygiene: https://www.health.harvard.edu/healthy-aging-and-longevity/sleep-hygiene-simple-practices-for-better-rest - CDC — About Sleep: https://www.cdc.gov/sleep/about/index.html - Harvard Medical School — Late-Night Eating Impact: https://hms.harvard.edu/news/late-night-eating-impact --- ### 3.5 Bedroom environment / Ambiente do quarto **English:** A quiet, dark, relaxing, and cool bedroom is consistently recommended by public health and sleep organizations. The National Sleep Foundation commonly suggests a bedroom temperature around 60–67°F / 15.5–19.4°C, though comfort varies by person, climate, bedding, age, and health status. The CDC and AASM recommend keeping the room cool and relaxing rather than treating one number as universal. **Português:** Um quarto silencioso, escuro, relaxante e fresco é recomendado de forma consistente por instituições de saúde e sono. A National Sleep Foundation costuma sugerir temperatura entre 60–67°F / 15,5–19,4°C, embora o conforto varie conforme pessoa, clima, roupa de cama, idade e saúde. CDC e AASM recomendam um ambiente fresco e relaxante, sem tratar um número único como regra universal. **App implementation:** - Room setup checklist: cool, dark, quiet, comfortable. - Suggested temperature range: 18–20°C as a practical default. - User can mark what is realistic for their home. **Evidence level:** Strong for environment; moderate for exact temperature range **Sources:** - CDC — About Sleep: https://www.cdc.gov/sleep/about/index.html - AASM Sleep Education — Healthy Sleep Habits: https://sleepeducation.org/healthy-sleep/healthy-sleep-habits/ - National Sleep Foundation — Sleep Tips: https://www.thensf.org/sleep-tips/ --- ### 3.6 Screens, brightness, and stimulation / Telas, brilho e estímulo **English:** Evening screen use can affect sleep through light exposure, mental stimulation, delayed bedtime, and habit loops. The CDC recommends turning off electronic devices at least 30 minutes before bed. Research in adults and young people links bedtime screen use with later sleep timing, shorter sleep duration, and poorer sleep quality. The effect is not only “blue light”; brightness, duration, content, and compulsive interaction matter too. **Português:** O uso de telas à noite pode afetar o sono por exposição à luz, estímulo mental, atraso do horário de dormir e ciclos de hábito. O CDC recomenda desligar eletrônicos pelo menos 30 minutos antes de dormir. Pesquisas em adultos e jovens associam telas perto da cama com horários de sono mais tardios, menor duração do sono e pior qualidade. O problema não é apenas “luz azul”; brilho, duração, conteúdo e interação compulsiva também importam. **App implementation:** - In-app screen intensity slider. - Warm interface mode. - Screen-time tracker inside the app. - Wind-down timer and phone-away prompt. **Evidence level:** Moderate to strong **Sources:** - CDC — About Sleep: https://www.cdc.gov/sleep/about/index.html - Hale et al., 2018 — Youth screen media habits and sleep: https://pmc.ncbi.nlm.nih.gov/articles/PMC5839336/ - Zhong et al., 2025 — Electronic Screen Use and Sleep Duration and Timing in Adults: https://pmc.ncbi.nlm.nih.gov/articles/PMC11950897/ --- ### 3.7 Wind-down routine and stimulus control / Rotina de desaceleração e controle de estímulos **English:** A predictable pre-sleep routine helps reduce arousal and trains the brain to associate the bedroom with sleep. For chronic insomnia, behavioral treatments such as CBT-I, stimulus control, sleep restriction, relaxation therapy, and brief behavioral treatment have stronger clinical support than generic “sleep hacks.” The app is not CBT-I, but it borrows low-risk behavioral ideas: routine, cueing, consistency, and reducing stimulation. **Português:** Uma rotina previsível antes de dormir ajuda a reduzir o estado de alerta e treina o cérebro a associar o quarto ao sono. Para insônia crônica, tratamentos comportamentais como TCC-I, controle de estímulos, restrição do sono, relaxamento e terapias breves têm suporte clínico mais forte do que “hacks” genéricos. O app não é TCC-I, mas usa ideias comportamentais de baixo risco: rotina, pistas ambientais, consistência e redução de estímulos. **App implementation:** - 60-minute wind-down mode. - Breathing animation. - Checklist sequence: plan tomorrow, dim lights, phone away, calm activity. - No punishment for missing items; positive habit reinforcement. **Evidence level:** Strong for behavioral treatment in insomnia; moderate for generic bedtime routines **Sources:** - AASM guideline — Behavioral and psychological treatments for chronic insomnia disorder in adults: https://pmc.ncbi.nlm.nih.gov/articles/PMC7853203/ - Harvard Division of Sleep Medicine — Adopt Good Sleep Habits: https://sleep.hms.harvard.edu/education-training/public-education/sleep-and-health-education-program/sleep-health-education-93 - AASM Sleep Education — Healthy Sleep Habits: https://sleepeducation.org/healthy-sleep/healthy-sleep-habits/ --- ## 4. Optional or caution items / Itens opcionais ou com cautela ### 4.1 Mouth taping and nasal breathing / Tapar a boca e respiração nasal **English:** Nasal breathing can be beneficial, and nasal strips may help some people with mild nasal airflow limitation. However, mouth taping has limited evidence and potential risks. Cleveland Clinic warns that mouth taping may cause skin irritation, anxiety, and breathing difficulty, and should not be used by people who snore, have sleep apnea, nasal obstruction, or breathing problems. A small study suggested possible benefit in mild obstructive sleep apnea among mouth breathers, but this is not enough to make it a default recommendation. **Português:** Respirar pelo nariz pode ser benéfico, e dilatadores nasais podem ajudar algumas pessoas com leve limitação de fluxo nasal. Porém, tapar a boca para dormir tem evidência limitada e riscos potenciais. A Cleveland Clinic alerta que a prática pode causar irritação na pele, ansiedade e dificuldade para respirar, e não deve ser usada por pessoas que roncam, têm apneia do sono, obstrução nasal ou problemas respiratórios. Um pequeno estudo sugeriu possível benefício em apneia obstrutiva leve em respiradores bucais, mas isso não basta para tornar a prática uma recomendação padrão. **App implementation:** - Not included as a default checklist item. - If mentioned, appears as “caution / optional.” - Safer alternatives: side sleeping, nasal strips, treating congestion, medical evaluation for snoring/apnea. **Evidence level:** Weak / caution **Sources:** - Cleveland Clinic — Is Mouth Tape Safe To Use While Sleeping?: https://health.clevelandclinic.org/mouth-taping - Lee et al., 2022 — Mouth-taping in mouth-breathers with mild OSA: https://pmc.ncbi.nlm.nih.gov/articles/PMC9498537/ --- ### 4.2 Melatonin / Melatonina **English:** Melatonin is not a general “sleeping pill.” It is a circadian timing hormone. Short-term use appears safe for most people, but long-term safety data is limited. It may be useful for jet lag, delayed sleep phase, shift work, or specific circadian rhythm problems. It should not replace consistent routines, light management, and medical evaluation when sleep problems persist. **Português:** Melatonina não é simplesmente um “remédio para apagar”. Ela é um hormônio de sinalização circadiana. O uso de curto prazo parece seguro para a maioria das pessoas, mas faltam dados de segurança de longo prazo. Pode ser útil para jet lag, atraso de fase do sono, trabalho em turnos ou problemas específicos de ritmo circadiano. Não deve substituir rotina consistente, manejo de luz e avaliação médica quando o problema persiste. **App implementation:** - Not a default recommendation. - Appears only as educational note. - Encourages medical guidance for repeated use. **Evidence level:** Moderate for specific circadian uses; caution for chronic unsupervised use **Sources:** - NIH NCCIH — Melatonin: What You Need To Know: https://www.nccih.nih.gov/health/melatonin-what-you-need-to-know - Mayo Clinic — Melatonin: https://www.mayoclinic.org/drugs-supplements-melatonin/art-20363071 --- ### 4.3 Magnesium, L-theanine, apigenin and supplement stacks / Magnésio, L-teanina, apigenina e “stacks” **English:** Supplement stacks should be considered optional. Some people report benefit from magnesium or L-theanine, but evidence varies depending on population, dose, product quality, sleep complaint, and medication interactions. Supplements can interact with medications, alcohol, sedatives, pregnancy, kidney disease, liver disease, and other conditions. **Português:** “Stacks” de suplementos devem ser considerados opcionais. Algumas pessoas relatam benefício com magnésio ou L-teanina, mas a evidência varia conforme população, dose, qualidade do produto, tipo de queixa de sono e interações medicamentosas. Suplementos podem interagir com remédios, álcool, sedativos, gravidez, doença renal, doença hepática e outras condições. **App implementation:** - No supplement schedule as a core feature. - Optional note: “Ask a healthcare professional if using regularly.” - The app emphasizes behavior first. **Evidence level:** Weak to moderate depending on supplement and person **Source:** - NIH NCCIH — Sleep Disorders and Complementary Health Approaches: https://www.nccih.nih.gov/health/sleep-disorders-and-complementary-health-approaches --- ### 4.4 Sleep scores and wearables / Pontuações de sono e wearables **English:** Wearables can help users notice patterns, but they should not become the main target. Consumer sleep trackers estimate sleep stages indirectly and may not match clinical sleep testing. Chasing a perfect score can increase anxiety and worsen sleep in some users. The app therefore focuses on subjective recovery, energy, mood, and consistency. **Português:** Wearables podem ajudar a perceber padrões, mas não devem virar o alvo principal. Rastreadores de sono de consumo estimam estágios de sono indiretamente e podem não corresponder a exames clínicos. Buscar uma pontuação perfeita pode aumentar ansiedade e piorar o sono em algumas pessoas. Por isso, o app foca em recuperação subjetiva, energia, humor e consistência. **App implementation:** - No sleep-score obsession. - Simple reflection: “How do you feel today?” - Habit trend > single-night perfection. **Evidence level:** Moderate practical caution --- ## 5. Practical thresholds used in the PWA / Parâmetros práticos usados no PWA | Item | Default value | Why / Por quê | Evidence level | |---|---:|---|---| | Wake time consistency | ±30–60 min | Keeps circadian rhythm stable | Strong | | Morning daylight | 10–30 min when possible | Anchors circadian timing | Strong/moderate | | Caffeine cutoff | 8 hours before bedtime | Reduces risk of delayed sleep and poorer sleep quality | Strong | | Last large meal | 3 hours before bedtime | Reduces reflux/digestion burden; 5h optional | Moderate/strong | | Screen cutoff | 30–60 min before bedtime | Reduces light/stimulation and delayed bedtime | Moderate/strong | | Bedroom temperature | ~18–20°C default | Cool environment supports sleep; individual comfort matters | Moderate | | Wind-down routine | 30–60 min | Lowers arousal and strengthens sleep cues | Moderate/strong | | Alcohol before bed | Avoid | Can fragment sleep and reduce REM quality | Strong/moderate | --- ## 6. PWA feature mapping / Mapeamento das funcionalidades do PWA | App feature | Scientific/behavioral rationale | Notes | |---|---|---| | Minimum checklist | Reduces cognitive load and builds consistency | Small daily actions beat complex protocols | | Full checklist | Allows personalization for advanced users | Avoids rigid one-size-fits-all advice | | Bedtime/wake clock | Supports regular rhythm | User-defined, not “5 AM club” dogma | | Caffeine cutoff calculator | Converts evidence into action | Default: bedtime minus 8h | | Meal cutoff calculator | Converts digestion timing into action | Default: bedtime minus 3h | | Wind-down timer | Creates predictable pre-sleep cue | Helps reduce “one more thing” behavior | | Breathing animation | Low-risk relaxation cue | Not a treatment for anxiety or insomnia by itself | | Warm/dim interface | Reduces app brightness and visual stimulation | Does not change system-wide display settings | | Screen-time tracker | Makes evening device use visible | App-only tracking, not OS-level screen time | | Notifications | Habit cueing | Requires permission; avoid excessive reminders | | Export/import JSON | User autonomy and data portability | Privacy-friendly local-first design | --- ## 7. What the app should not claim / O que o app não deve prometer ### English The app should **not** claim that it cures insomnia, diagnoses sleep apnea, replaces medical treatment, guarantees deep sleep, changes phone brightness system-wide, or proves that a supplement stack works for everyone. ### Português O app **não** deve prometer que cura insônia, diagnostica apneia do sono, substitui tratamento médico, garante sono profundo, altera o brilho do celular no sistema inteiro ou prova que um stack de suplementos funciona para todos. --- ## 8. When to seek professional help / Quando procurar ajuda profissional ### English A user should consider medical or sleep-specialist evaluation if they have: - Loud snoring, choking, gasping, or witnessed pauses in breathing. - Excessive daytime sleepiness despite enough time in bed. - Insomnia lasting more than 3 months or causing significant impairment. - Restless legs, unusual movements, or violent dream enactment. - Dependence on alcohol, sedatives, or supplements to sleep. - Shift-work sleep problems that affect safety. - Depression, anxiety, panic, pain, reflux, or other medical issues affecting sleep. ### Português O usuário deve considerar avaliação médica ou de especialista em sono se tiver: - Ronco alto, engasgos, falta de ar ou pausas respiratórias observadas. - Sonolência diurna excessiva apesar de tempo suficiente na cama. - Insônia por mais de 3 meses ou com prejuízo importante. - Pernas inquietas, movimentos incomuns ou comportamento agitado durante sonhos. - Dependência de álcool, sedativos ou suplementos para dormir. - Problemas de sono por trabalho em turnos que afetem segurança. - Depressão, ansiedade, pânico, dor, refluxo ou outras condições afetando o sono. --- ## 9. Design philosophy / Filosofia de design ### English The app should feel calm, beautiful, and motivating without becoming obsessive. The goal is not to maximize a number; the goal is to help the user build repeatable behaviors that make sleep more likely. Good sleep design principles: 1. **Reduce friction:** one tap to complete a habit. 2. **Avoid shame:** missed habits are data, not failure. 3. **Use rhythm:** morning, daytime, evening, bedtime. 4. **Personalize:** chronotype and lifestyle matter. 5. **Prefer low-risk interventions:** light, rhythm, caffeine, bedroom, routine. 6. **Label uncertainty:** supplements and mouth taping are not core behaviors. 7. **Protect privacy:** local storage first; export only when user chooses. ### Português O app deve ser calmo, bonito e motivador sem virar obsessivo. O objetivo não é maximizar um número; o objetivo é ajudar o usuário a construir comportamentos repetíveis que aumentem a chance de dormir melhor. Princípios de bom design para sono: 1. **Reduzir atrito:** um toque para concluir um hábito. 2. **Evitar culpa:** hábito perdido é dado, não fracasso. 3. **Usar ritmo:** manhã, dia, noite, hora de dormir. 4. **Personalizar:** cronotipo e estilo de vida importam. 5. **Preferir intervenções de baixo risco:** luz, ritmo, cafeína, quarto, rotina. 6. **Sinalizar incerteza:** suplementos e tapar a boca não são hábitos centrais. 7. **Proteger privacidade:** armazenamento local primeiro; exportação só quando o usuário quiser. --- ## 10. Source list / Lista de fontes 1. CDC — About Sleep: https://www.cdc.gov/sleep/about/index.html 2. AASM Sleep Education — Healthy Sleep Habits: https://sleepeducation.org/healthy-sleep/healthy-sleep-habits/ 3. Harvard Division of Sleep Medicine — Adopt Good Sleep Habits: https://sleep.hms.harvard.edu/education-training/public-education/sleep-and-health-education-program/sleep-health-education-93 4. Harvard Health — Sleep hygiene: https://www.health.harvard.edu/healthy-aging-and-longevity/sleep-hygiene-simple-practices-for-better-rest 5. Harvard Medical School — Late-Night Eating Impact: https://hms.harvard.edu/news/late-night-eating-impact 6. Sleep Foundation — Caffeine and Sleep Problems: https://www.sleepfoundation.org/nutrition/caffeine-and-sleep 7. Gardiner et al., 2023 — The effect of caffeine on subsequent sleep: https://www.sciencedirect.com/science/article/pii/S1087079223000205 8. Blume et al., 2019 — Effects of light on human circadian rhythms, sleep and mood: https://pmc.ncbi.nlm.nih.gov/articles/PMC6751071/ 9. CDC/NIOSH — The Color of the Light Affects Circadian Rhythms: https://www.cdc.gov/niosh/work-hour-training-for-nurses/longhours/mod2/20.html 10. Hale et al., 2018 — Youth screen media habits and sleep: https://pmc.ncbi.nlm.nih.gov/articles/PMC5839336/ 11. Zhong et al., 2025 — Electronic Screen Use and Sleep Duration and Timing in Adults: https://pmc.ncbi.nlm.nih.gov/articles/PMC11950897/ 12. AASM guideline — Behavioral and psychological treatments for chronic insomnia disorder in adults: https://pmc.ncbi.nlm.nih.gov/articles/PMC7853203/ 13. National Sleep Foundation — Sleep Tips: https://www.thensf.org/sleep-tips/ 14. Cleveland Clinic — Is Mouth Tape Safe To Use While Sleeping?: https://health.clevelandclinic.org/mouth-taping 15. Lee et al., 2022 — Mouth-taping in mouth-breathers with mild OSA: https://pmc.ncbi.nlm.nih.gov/articles/PMC9498537/ 16. NIH NCCIH — Melatonin: What You Need To Know: https://www.nccih.nih.gov/health/melatonin-what-you-need-to-know 17. Mayo Clinic — Melatonin: https://www.mayoclinic.org/drugs-supplements-melatonin/art-20363071 18. NIH NCCIH — Sleep Disorders and Complementary Health Approaches: https://www.nccih.nih.gov/health/sleep-disorders-and-complementary-health-approaches --- ## 11. Suggested README snippet / Trecho sugerido para README ### English This PWA is based on evidence-informed sleep hygiene and circadian rhythm principles. It helps users translate healthy sleep behaviors into daily actions: regular sleep timing, morning light, caffeine cutoff, meal timing, evening dimming, reduced screen stimulation, wind-down routines, and bedroom optimization. It does not diagnose or treat sleep disorders. ### Português Este PWA é baseado em princípios de higiene do sono e ritmo circadiano informados por evidências. Ele ajuda usuários a transformar hábitos saudáveis de sono em ações diárias: regularidade de horários, luz pela manhã, corte de cafeína, horário das refeições, redução de luz à noite, menos estímulo de telas, rotina de desaceleração e melhoria do ambiente do quarto. Ele não diagnostica nem trata distúrbios do sono.