Dr. Nishi Bhopal MD, a psychiatrist and sleep medicine physician, explains how to evaluate patients who wake every few hours despite a “normal” sleep study, emphasizing that a single study especially a home sleep apnea test does not rule out sleep apnea or other causes of sleep fragmentation because it mainly measures breathing rather than sleep architecture, limb movements, or narcolepsy. She presents a case where repeated awakenings were driven by upper airway resistance that increased breathing effort and sympathetic activation without meeting apnea criteria. She frames fragmented sleep as recurrent nervous system activations and offers a practical clinical approach: systematically assess four categories of common drivers food/metabolic factors (e.g., reflux, alcohol, hypoglycemia, low ferritin/B12), environmental factors (light, noise, temperature, circadian disruption), emotional/psychological activation (stress, anxiety, rumination, trauma, conditioned arousal), and medical causes (pain, endocrine disorders, RLS/PLMs, sleep apnea, narcolepsy), noting many patients have multiple contributors.