Sleep is essential for overall well-being and vital to maintaining health. As a complex process with various stages and cycles, sleep can be evaluated using polysomnography and consumer sleep trackers, although the latter are less accurate for monitoring sleep stages. Sleep needs and patterns evolve throughout life, from infancy to older adulthood, with adults ages 18 to 64 years typically requiring 7 to 9 hours per night for optimal health. Insufficient sleep is associated with an increased risk of chronic conditions, including cardiovascular disease, diabetes, and obesity, and a weakened immune system. It also impairs cognitive function, decreases productivity and quality of life, and increases the risk of motor vehicle crashes. Sleep deprivation is closely tied to mental health issues, such as anxiety and depression. Although napping or sleep banking may offer temporary relief from sleep deprivation, they cannot be a substitute for regular, high-quality sleep. Consistently sleeping more than 9 to 10 hours per night, known as hypersomnia, has been linked to health issues including weight gain, mental health conditions, and cardiovascular disease. Prioritizing appropriate sleep duration and quality is essential for physical and mental health, helps prevent a variety of health issues, and promotes better daily functioning.

Case 1. BT is a 46-year-old man who comes to your office for a health maintenance examination. His blood pressure is 144/88 mm Hg, and body mass index is 28.5 kg/m². The rest of his physical examination and results of routine laboratory tests are unremarkable. He reports feeling more fatigued and less motivated to exercise in the past year. He likes to watch videos on his tablet until late at night and usually sleeps about 6 hours per night. He says he used to be able to function well on little sleep, but it seems lack of sleep is now catching up with him.