I’m a registered sleep tech (Polysomnographic Technologist), so the first thing I’m required to tell you is… consult your doctor. There a many factors (physiological, psychological, and environmental) than can affect your sleep, so your individual case may or may not be helped by the advice (mine or others) provided in this forum.
That being said, there are several sleep resources available on the web. One is the National Institute of Health, who has an overview of sleep in a pdf document. The web page is: nhlbi.nih.gov/health/public/sleep/healthysleepfs.htm
Some of the advice in this article may make sound childishly obvious, but you’d be surprised about the sleep habits I hear about from all the patients I see in our lab. (One young guy brought his CD player to the lab, and said he listens to hard-rock music while going to sleep. I made him leave it off, and he slept fine.)
Regarding a mattress, my wife and I went to a place where you can try Tempur-Pedics, Select Comforts, and others. We chose the Select Comfort Sleep Number bed. Other mattresses might be fine for you, but I love my Sleep Number bed. We bought it last year, and my back feels much better.
As far as waking up groggy, there’s a fairly new product on the market that I’m considering for my son who’s just starting law school. It’s called Sleeptracker (See www.sleeptracker.com)). The Amazon.com reviews look favorable. The idea makes sense, because someone with a normal sleep architecture goes through several stages of sleep throughout the night every 90-120 minutes. Some stages are deeper than others, and if you’re woken up during them you’ll probably feel groggy. This device purportedly senses when you’re in an arousal (not a sexual arousal, but when you’re transitioning from a lower sleep stage to a lighter one, or from sleep to wake). Then, if it’s within the time window for when you’re supposed to wake up, it sets off the alarm.
Again, contact your doctor. If you have sleep apnea, or another physiological or psychological condition, there is little or nothing that changing environmental conditions (bed, noise level, etc.) will help. I wear a CPAP mask, and sleep much better with it. (And my wife & kids don’t have to hear me snore.) Sleep apnea has been linked to more and more problems, including hypertension, depression, etc. It’s small wonder, considering that you’re reducing the oxygen available to you brain and body during these apneic events. My doctor recently told me about a case (he didn’t provide name or details, of course) in which a patient had a disease that neither he nor the Mayo clinic could resolve. However, when the patient was sleep-tested for an unrelated issue, then put on CPAP, the mysterious disease was resolved.
Regarding the appropriate amount of time, it varies from person to person, and it various for an individual based on different conditions (environment, health, changes as they age, etc.) Generally speaking it could be 6 to 10 hours. Keep in mind, though, that the lower amount of slow-wave sleep and REM sleep you get, the less rested you’ll feel. The amount of the various stages can be affected by medications, caffeine, apneas, periodic leg movement syndrome, etc. Time in bed is not an indicator of the quality of sleep, as you already know too well.
Hope this helps!