Sleep duration refers to the total amount of time a person spends sleeping within a 24-hour period. It varies by age and individual needs, with recommendations suggesting that adults aim for 7 to 9 hours of sleep each night. Insufficient sleep can lead to various health issues, including impaired cognitive function and weakened immune response. Factors influencing sleep duration include lifestyle choices, stress levels, and environmental conditions. Sleep disorders, such as insomnia or sleep apnea, can also significantly affect how long a person sleeps. Maintaining a consistent sleep schedule and creating a restful environment can help improve overall sleep duration.