Why do I feel tired all day even after sleeping?

Feeling tired despite sleeping enough usually comes down to sleep quality rather than quantity. If you're not reaching deep or REM sleep stages, you won't feel rested regardless of hours spent in bed. Common causes include sleep apnea, where breathing interruptions prevent restorative sleep, often without you realizing it. Stress, anxiety, and screen exposure before bed also fragment sleep cycles. Other factors include poor diet, dehydration, sedentary lifestyle, or underlying conditions like anemia, thyroid problems, or diabetes. Caffeine consumed too late in the day can disrupt sleep architecture even if you fall asleep easily. If this is persistent, seeing a doctor is worthwhile since chronic fatigue can signal something that needs proper diagnosis and treatment.