As long as you are not tired, you are getting enough sleep. If you are tired, you may not be getting enough sleep. You might be suffering from sleep deprivation. That's the short answer.
Although everybody is different, most adults need about 7-8 hours of sleep a day. Young children generally sleep as much as they need very naturally - they get cranky when tired. Teenagers may need up to 10 hours of sleep to help them grow and learn! Plus, their natural circadian rhythm tends to run late - going to be at midnight and waking up at 9-10am, for example. Unfortunately because schools start early in the morning, the teenage years are when many people get into a bad pattern of chronic sleep deprivation. Hopefully as a young adult, one learns to sleep better and can continue this for many years. As one ages, one tends to sleep less at night and may benefit from a nap during the day. The current thinking is that elderly still need as much total sleep as they needed during the adult years but they often do not get it due to mounting medical problems.
You can find out how much sleep is right for you with the following procedure. It is a 2 week self-experiment.
1. Guess how much sleep would be adequate - for most adults it would be 8 hours.
2. For a week (7 full days), set your alarm clock for the same time each day.
3. Go to bed at an hour that would let you get the number of hours you think you need.
4. Record when you go to bed and when you wake up.
5. Do not take any naps during the day, and do not let yourself stay up later than you should.
6. Every morning when you wake up, turn on as many lights as you can in the rooms that you occupy if the rooms are dark in the mornings. If you eat breakfast or read the newspaper, place a lamp (preferably a white light instead of an incandescent bulb) next to where you are. This not only helps to wake you up but may also improve your mood during the day.
7. Try to decrease your caffeine intake if you drink more than one to two 8 ounce cups of coffee a day. Try not to drink any after 4pm. Also, limit your alcohol intake to one to two servings a day.
8. After the first 3-4 days, you should naturally feel sleepy when you need to go to bed. Listen to your body! Go to bed when you feel sleepy.
9. By the end of the week, take the average number of hours you slept the previous 3 nights. That will give you a good estimate of what you need.
10. Starting in the second week of this experiment, use the calculation from the first week and repeat steps 2-8.
11. At the end of the second week, take the average of the last 3 nights. That is the number of hours you need.
If no amount of rest is refreshing, you may have a sleep disorder, such as sleep apnea.
For women, hormonal changes may impact amount of sleep needed. Also, many medications can lengthen or shorten the amount of sleep you need, even if it is not their main purpose. Some herbal medications or teas affect sleep as well. Common drugs that impact sleep include antidepressants, St. John's wart, stimulants, steroids, antihistamines, antipsychotics, alcohol, anxiolytics, and many others. Talk to your doctor if you believe your medications are causing sleep problems.
If you feel well and function perfectly with only 6-7 hours of sleep a night, then you are lucky! If you find that you function best with 9 hours of sleep, then you need to adjust your life schedule to accommodate those hours. Chronic sleep deprivation makes you far less productive during the day, so you may actually end up getting less done. Again, if you are not tired, then you are getting enough sleep!
If you are having trouble with your sleep, learn about the drug-free SleepPhones System!