some aspects of sleep become more problematic in middle age. The total number of hours slept usually remains the same as in early adulthood, but beginning in the forties, wakeful periods are more frequent and there is less of the deepest type of sleep. the amount of time spent lying awake in bed at night begins to increase in middle age, and this can produce a feeling of being less rested in the morning. Sleep-disordered breathing and restless legs syndrome become more prevalent in middle age. A recent study found that middle-aged adults who sleep less than six hours a night on average had an increased risk of developing stroke symptoms. Another study found that change in sleep duration across five years in middle age was linked to cognitive functioning. In this study, a decrease from 6, 7, or 8 hours of sleep and an increase from 7 or 8 hours were related to lower scores on most assessments of cognitive functioning. Sleep problems in middle-aged adults are more common among those who use a higher number of prescription and nonprescription drugs, are obese, have cardiovascular disease, or are depressed.