What is the optimum amount of sleep we should be aiming for?

HI AngharadM
The amount of sleep you need is entirely personal, even the same person can require different amounts of sleep at different times in their life dependent on diet, exercise, stress levels, anxiety/worry, happiness, having young children and a variety of other factors.
What's really important is how your time asleep leaves you feeling. If you awake naturally feeling fantastic after only six hours then you're probably getting enough. If you awake feeling exhausted after pressing the snooze button five times, then I suspect that there is something going on in your life that's affecting the quality as well as the quantity of your sleep.
If you believe you are not getting enough sleep then you're probably not. And if not it's important to understand the reasons why. Getting enough sleep is critical for optimum functioning of mind and body - there's a reason why sleep deprivation is used as a form of torture!
If you are not getting enough sleep I heartily recommend using a deep relaxation recording to help you (you can download a free one here http://www.hypnogogo.co.uk/promotions/hypnogoslow-release-your.html), there are also many people who swear by binaural beats to encourage sleep. Most importantly though try to consider the cause of your sleeplessness and start trying to solve those issues (a hypnotherapist could help).
Although from your question above, you don't make it clear that sleeplessness is the issue, it may be that you are getting enough sleep however are lucky enough to feel great on less than the standard eight hours - if so enjoy the extra time and don't worry about it!
Best wishes and sweet dreams, Claire

we all need 8hr each night but as we age we need less so get to be at 1030 up at 6 am is the best way to get all the sleep we need

Some say 8 hours but really one should figure it out for ones self. I like a good 7 hours but my partner varies and can feel fine off 4 hours. The best sleep is a few hours before midnight. Go to sleep in a cold or cool room. Don't turn the lights on when you get up to use the toilet (as this simulates day time and your body wakes up). Don't have cafe or strong tea before bed. If you can't fall to sleep get up but don't over stimulate yourself. Then return to bed when sleepy.

Sleep is one of the richest topics in science today: why we need it, why it can be hard to get, and how that affects everything from our athletic performance to our income. Daniel Kripke, co-director of research at the Scripps Clinic Sleep Center in La Jolla, Calif., has looked at the most important question of all. In 2002, he compared death rates among more than 1 million American adults who, as part of a study on cancer prevention, reported their average nightly amount of sleep. To many, his results were surprising, but they've since been corroborated by similar studies in Europe and East Asia. Kripke explains.
Q: How much sleep is ideal?
A: Studies show that people who sleep between 6.5 hr. and 7.5 hr. a night, as they report, live the longest. And people who sleep 8 hr. or more, or less than 6.5 hr., they don't live quite as long. There is just as much risk associated with sleeping too long as with sleeping too short. The big surprise is that long sleep seems to start at 8 hr. Sleeping 8.5 hr. might really be a little worse than sleeping 5 hr.
Morbidity [or sickness] is also "U-shaped" in the sense that both very short sleep and very long sleep are associated with many illnesses—with depression, with obesity—and therefore with heart disease—and so forth. But the [ideal amount of sleep] for different health measures isn't all in the same place. Most of the low points are at 7 or 8 hr., but there are some at 6 hr. and even at 9 hr. I think diabetes is lowest in 7-hr. sleepers [for example]. But these measures aren't as clear as the mortality data.
I think we can speculate [about why people who sleep from 6.5 to 7.5 hr. live longer], but we have to admit that we don't really understand the reasons. We don't really know yet what is cause and what is effect. So we don't know if a short sleeper can live longer by extending their sleep, and we don't know if a long sleeper can live longer by setting the alarm clock a bit earlier. We're hoping to organize tests of those questions.
One of the reasons I like to publicize these facts is that I think we can prevent a lot of insomnia and distress just by telling people that short sleep is O.K. We've all been told you ought to sleep 8 hr., but there was never any evidence. A very common problem we see at sleep clinics is people who spend too long in bed. They think they should sleep 8 or 9 hr., so they spend [that amount of time] in bed, with the result that they have trouble falling asleep and wake up a lot during the night. Oddly enough, a lot of the problem [of insomnia] is lying in bed awake, worrying about it. There have been many controlled studies in the U.S., Great Britain and other parts of Europe that show that an insomnia treatment that involves getting out of bed when you're not sleepy and restricting your time in bed actually helps people to sleep more. They get over their fear of the bed. They get over the worry, and become confident that when they go to bed, they will sleep. So spending less time in bed actually makes sleep better. It is in fact a more powerful and effective long-term treatment for insomnia than sleeping pills.
Read more: http://www.time.com/time/health/article/0,8599,1812420,00.html#ixzz1fD5yXsc9

It really does depend on the individual's needs. There have been some studies that suggest 6.5-7.5 is ideal - any less or any more can be associated with many illnesses, depression, obesity and so forth.
The important question to ask yourself is "how do you feel?" are you feeling like you have enough energy to get through the day? If not, go to bed earlier and when you naturally wake up (even if this is before when you normally would) then get up. We have a tendency to linger... Or there are some people who struggle with good quality sleep and insomnia so they need to look at what is happening in their lives that is affecting this - what in their environment, relationships or within themselves is contributing to their unrest?
A good therapist can help someone overcome their concerns and get back to sleeping soundly by teaching them strategies for dealing with emotional triggers and stress in a healthy and productive way.

It isn't necessarily the amount of sleep, more the quality of sleep. Do you wake up feeling refreshed and ready for the day? If not, using complementary therapies such as homeopathy or herbs can help correct this. It is vital to look at the cause of poor quality sleep or a desire to over-sleep. Often certain organs in our bodies can be out of sync and not functioning as well as they should be which means we can wake up at certain times of the night. According to the Chinese Organ Clock for example between 1am and 3am is Liver detox time, so if you tend to wake up at this time then it could suggest the Liver is not functioning as well as it should be and requires support. Ideally, we should also aim to go to bed at the same time and wake up at the same time everyday as our organs stick to a strict schedule and if this changes often it can affect the way we feel. I hope that helps. Claire