What Is A Sleep Study And When Is A Sleep Study Indicated? A sleep study involves staying overnight in the sleep laboratory and being hooked up to a machine which is monitored by sleep technologists. Sleep patterns can be studied in the laboratory using machines which record brainwave activity, breathing, heart rate and limb movements during sleep. At least 6 hours of sleep are recorded using electrodes attached to the scalp and limbs, special belts across the chest and abdomen, airflow monitors and ECG leads. A sleep study is usually indicated in patients in whom sleep related breathing disorders and abnormal movements in sleep are suspected, to rule out sleep apnoea and nocturnal seizures. Patients with recurrent awakenings of unclear cause should also undergo a sleep study to determine the cause of the repeated arousals.