Enough to feel awake, aware, and creative throughout the day. Most Americans never feel fully rested, which affects your productivity, pleasure, mood, and happiness - plus how long you'll live. Consider these facts:
1. Sleep is a part of rest, the way your body regenerates itself. . You're not a machine but a living being. Think of acorns. You know an acorn can grow into a great oak tree. You're body rebuilding is just as regenerative and magnificent, but if the rebuild doesn't work properly, you get sick. Sleep deprive an animal long enough and it dies; partially sleep deprive humans, even just for less than six hours a night, and they die younger.
2. Individuals need very different amounts of sleep. Though most of the population will survive pretty well on 7-8 hours of sleep (not bed time, sleep) per night, some do well on three hours, while others need nine. To start to figure this out, look at how much total sleep time you get on weekend and vacation days.
3. Different ages need very different amounts of sleep. Teenagers need around 9.5 hours a night to be able to learn, remember new moves in sports, control weight, prevent depression and be reasonably happy. They are generally getting around 6.5-7.5 hours a night, though sleep interruptions from electronic devices make the overall picture worse (more later.)
4. People who don't get enough sleep have A. More heart disease, especially when they're getting less than 6 hours of sleep B. More weight gain C. More depressions D. More infections, especially colds D. Less alertness and awareness than they need to get through the often exhausting requirements of work and family.
5. You don't want to be awakened at night, as frequent sleep interruption means you don't get into the deeper phases of sleep, like deep sleep and REM. These parts of sleep are needed for memory, learning, and lots of other body rebuilding. Wake up a young perfect sleeper every three -four minutes, even for a few seconds, and they often will tell you they feel like they were up all night. That's the problem with keeping your cell phone near your bed - you need uninterrupted sleep to obtain the deeper phases of sleep.
That's a big problem with primary sleep disorders like sleep and apnea and restless legs syndrome, which frequently wake people up without their knowing it, which makes you feel tired all day. That's how the nighttime interruptions of electronic devices can produce so much disruption to useful rest that they dramatically harm your productivity, memory, learning, and mood.
6. People really don't really how much sleep they objectively get. My record is a woman who woke up 1200 times in our sleep lab and told everyone she'd slept all night during her best night's sleep in 4 years! One study showed that when people were awakened after a full 10 minutes of light sleep, fully half thought they were awake the whole time.
That's one major reason pilots on Pacific flights come in 2-3 teams. Pilots, conductors, and drivers are often falling asleep while they work, even with their eyes open. Often they are unaware they're asleep - which may well include you on the road.
The American view of sleep as a light switch that turns off as we jump into bed to "lie down and die" is a fantasy. Our alertness shifts relentlessly but predictably during the 24 hour day, as any shift worker can tell you. We really don't fall asleep instantly. We need to rest before we fall asleep, because too many of us too much of the time are all wired up. And most of us will never know that even on "perfect" nights we're briefly awakening 15-25 times.
So the amount of sleep you need should not be exactly 7.6 hours but what you need to be alert, awake, aware, and creative. Creativity especially demands enough rest time so that your brain can mix the previous day's experiences with old memories to produce the really new stuff that makes life so wonderfully interesting.
So experiment. Try out at least a few extra minutes of sleep for a week. One news director told me she forced herself to get enough rest and not work a whole weekend. She suddenly felt rejuvenated, filled with new ideas.
That's what real rest does. It's time to recognize you can and should regenerate your body the way you want. All I am saying is give sleep a chance.