A reader asks:

 How many hours a night of sleep does an adult need to stay healthy? Does alcohol help you get a good night’s rest?


Sleep need varies widely among individuals. A sign that you’re not getting enough is when you find yourself sleeping longer hours on days off compared with work days. Your goal should be to sleep the same hours all week long on a schedule that allows you to feel alert and energetic during the day. Statistically, it has been suggested that people who chronically sleep very long OR very short hours (for example, 10 hours or 5 hours) may have shorter life expectancy: but that’s just statistics, and doesn’t apply in every case. Some people sleep longer when they become depressed (or they become depressed when they sleep longer — we’re not sure!). In such cases, morning light therapy with earlier awakening can do the trick. Such people are often amazed that they do better with less sleep, and their impression that “if I could only sleep longer, I’d have more energy for day ahead” is proved wrong. As for alcohol, it may help knock you out, but the resulting sleep has poor physiological restorative quality and often leads to multiple awakenings during the night. Don’t do it!