Your sleep isn’t one long block — it moves in cycles of 90–120 minutes, shifting between light sleep, deep sleep, and REM (dreaming) sleep.
Between 3–5 AM, most people are in their final REM cycle — when brain activity increases and waking is more likely.
But why do some people wake up — and struggle to fall back asleep?
Common Medical & Lifestyle Causes:
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Stress & Anxiety
Cortisol spikes at night; racing thoughts disrupt sleep
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Depression
Early morning awakening is a classic symptom
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Hormonal Changes
Menopause, thyroid issues, or blood sugar drops
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Sleep Apnea
