Waking up between 3 a.m. and 4 a.m. is more common than many people think. It often happens during a lighter stage of sleep, when stress, noise, light, or physical discomfort can easily wake you. If it happens regularly, it may also be linked to issues like anxiety, sleep apnea, or other health conditions. Improving your sleep routine and speaking with a healthcare professional if the problem persists can help you get more restful nights.