Many people sleep for 7–8 hours but still wake up feeling tired. The problem is often not sleep duration, but sleep timing.
Sleep happens in cycles of approximately 90 minutes. Each cycle includes light sleep, deep sleep, and REM sleep. Waking up in the middle of a cycle can cause grogginess and fatigue.
Sleeping longer does not always mean better rest. Aligning your sleep and wake time with natural sleep cycles can significantly improve energy and focus.
Instead of guessing, a sleep calculator helps you find the best times to sleep or wake based on sleep cycles. I personally explored a simple guide that explains sleep cycles clearly and links to a practical calculator you can use immediately. 👉 **Sleep Cycle & Calculator Guide
Improving sleep does not always require supplements or expensive apps. Understanding sleep cycles and timing can make a real difference.
Is a sleep calculator accurate?
Sleep calculators use average sleep cycles. They provide guidance, not medical advice.
Why do I feel tired after 8 hours of sleep?
Waking up mid-sleep cycle can cause grogginess even after long sleep.