how much deep sleep is needed

Most adults need about 1.5 to 2 hours of deep sleep per night, which typically accounts for about 20-25% of total sleep time. For someone sleeping 7 to 8 hours, this translates to roughly 90 to 120 minutes of deep sleep. Deep sleep is crucial for physical recovery, tissue repair, immune system strengthening, and overall health. The amount of deep sleep needed can vary depending on age, health, and activity level, with deep sleep generally decreasing as people age.