Calculadora de Sono
Based on the science of 90-minute sleep cycles. Wake up at the end of a cycle - not in the middle - to feel more refreshed.
Sleep is when your body repairs muscle tissue, consolidates memories, and regulates hormones that control appetite and stress. The sleep cycle repeats approximately every 90 minutes, alternating between light sleep, deep sleep, and REM (rapid eye movement) sleep. Waking up in the middle of a sleep cycle leaves you feeling groggy, while waking at the end of a cycle leaves you feeling refreshed.
This calculator uses the standard 90-minute cycle to find optimal bedtimes and wake times. For most adults, 7-9 hours of sleep (4-6 complete cycles) is recommended for optimal health, recovery, and cognitive function. Consistency matters as much as duration — going to bed and waking at the same time each day helps regulate your circadian rhythm.
Poor sleep is linked to increased cortisol, reduced muscle recovery, impaired cognitive function, and weight gain. If you struggle with sleep quality, try limiting screen time 60 minutes before bed, keeping your bedroom cool (65-68°F / 18-20°C), and avoiding caffeine after 2 PM.
Como Funcionam os Ciclos de Sono
Sleep occurs in cycles of roughly 90 minutes, alternating between light sleep, deep sleep, and REM sleep. Waking up during deep sleep causes sleep inertia - that groggy, disoriented feeling. Waking at the end of a cycle, during light sleep, leaves you feeling naturally alert.
This calculator adds 15 minutes for falling asleep, then counts backward in 90-minute increments from your desired wake time to find optimal bedtimes that align with the end of sleep cycles.
Dicas para Dormir Melhor
- Keep a consistent sleep schedule, even on weekends
- Limit blue light exposure 1 hour before bed
- Keep your bedroom cool (65-68 F / 18-20 C)
- Avoid caffeine after 2 PM
- Avoid heavy meals within 3 hours of bedtime
A Ciência
Sleep is regulated by two systems: the circadian rhythm (your internal body clock, driven by light exposure) and sleep pressure (adenosine buildup throughout the day). Within each 90-minute sleep cycle, you progress through light sleep (N1, N2), deep sleep (N3), and REM sleep. Waking during deep sleep triggers sleep inertia; waking at cycle boundaries leaves you alert.
Sleep cycle research is based on the work of Kleitman and Dement (1957) on REM sleep and subsequent sleep architecture studies.
Relacionado
Sleep quality directly affects recovery and energy expenditure. Use our TDEE Calculator to align your nutrition with your activity and recovery needs.
Frequently Asked Questions
How many hours of sleep do I need?
Adults need 7-9 hours per night. Teenagers need 8-10, children need 9-12. Consistently getting less than 7 hours is associated with health risks.
What is a sleep cycle?
Sleep cycles last about 90 minutes and include light sleep, deep sleep, and REM sleep. Waking at a cycle end leaves you more refreshed.
When should I go to bed?
Based on 90-minute cycles and your wake time, optimal bedtimes align with cycle endpoints. For a 6 AM wake: 9 PM, 10:30 PM, or 12 AM.
How does sleep affect fitness?
Sleep repairs muscle tissue, consolidates memory, and regulates hormones. Lack of sleep increases cortisol and impairs recovery and performance.