GOING TO BED IS something you fight against as a child, becomes your whole raison d'etre when you hit your late teens, and is something you never seem to get enough of once you're a fully paid-up member of the rat race. No matter how adept you might be at burning the candle at both ends, too much work and play will eventually take their toll and even diehard party animals need their sleep. According to the Better Sleep Council (BSC; www.bettersleep.org ), an American non-profit-making association dedicated to educating the public about the importance of sleep and the sleeping environment, the average person needs about seven hours of shut-eye a night and spends one-third of his or her life in bed - the equivalent of about 220,000 hours. How well you sleep makes all the difference to your mental and physical condition, and your body will soon start to malfunction if constantly deprived of restorative rest. Although factors such as stress and caffeine are common causes of insomnia, if you find yourself constantly tossing and turning at night your bedroom could be to blame. A beautifully decorated room accessorised with Egyptian cotton sheets and mountains of colour-coordinated pillows can create an image of calm, but such aesthetically pleasing comfort isn't essential. 'Looking comfortable isn't the same as feeling comfortable - especially when it comes to your bed,' says Andrea Herman, director of the BSC. 'Many people invest in the visual element of their bed, but to get the full benefit of your investment you need to start with its foundation - the mattress.' Anyone who has spent the night on a lumpy, saggy mattress will agree. It is the mattress core (typically comprising springs, but it can be air or water depending on your preference) that supports your body, with the upholstery layers around it providing surface comfort and further reinforcement. A good mattress should be firm enough to support your body at all points, and when you're lying on your back it should keep your spine in the same position as a good standing posture. It shouldn't be so hard that it throws your hips and shoulders out of their normal curvature, or so soft that you find it difficult to move around naturally in your sleep. Space is also important and it is a proven fact that a bigger bed really is better. The Sleep Council in Britain ( www.sleepcouncil.org.uk ) says the ideal bed size for two adults is 160 centimetres by 200cm (a standard bed, 135cm by 190cm, apparently gives each person less room comparatively than a baby would have in a cot), and you and your partner should have enough room to change position comfortably without one of you ending up on the floor. In a town where space is often limited, try to buy the largest bed possible to fit your room and budget. Although a high-quality mattress should last longer than a cheaper model, it won't last forever. The mattress is used more than any other item of household furniture, so after about 10 years of wear and tear it's worth investing in a new one. In addition, your bodily needs change as you get older, demanding a different level of support at 60, for instance, than as a sprightly 20-something. If you think your mattress has seen better nights - tell-tale signs are waking up feeling stiff for no apparent reason or a restless night's sleep - test some beds in various home stores. Once you have sorted out your mattress you can dress your bed to your heart's content, bearing in mind that natural fibres such as cotton and linen are better than synthetic mixes because they help the skin to breathe. According to Herman, millions of people suffer needless sleep deprivation due to environmental factors in the bedroom - notably light, noise and temperature - which are easily controllable. 'Consumers who recognise there is something wrong with their sleep environment and do something about it, do themselves an enormous favour,' she says. 'They sleep better and will greet the day well rested.' Everyone has an internal body clock that regulates sleeping patterns, body temperature and other such functions, and it is most strongly influenced by light. Bright lights or anything less than pitch dark can prevent you from falling asleep or from sleeping as deeply as you need. 'Made-to-measure curtains can be lined with blackout material, but if you don't want to fork out for new drapes buy some window blinds, and use them together with the curtains you have,' says Herman. And if all else fails, an eye mask should do the trick. Heavier curtains will also muffle external noise to a degree, and some people believe the constant sound of a fan or air-conditioner inside will over-ride sharp intermittent noise, such as traffic, outside. While not a particularly romantic concept, earplugs can help too. Another major source of sleep disturbance is temperature. Most sleep scientists believe the optimal bedroom temperature is a relatively cool 16-18 degrees Celsius so as to mimic the body's internal temperature, which drops to its lowest level during sleep to conserve energy. In many countries you can simply open a window for the desired decrease in temperature, but here you can be sweltering when you go to bed only to wake up feeling as though you're in the Arctic wastes, having switched on the air-conditioning. A summer-weight duvet or light throw gets round this problem, particularly if sleeping partners' tolerance for heat or cold differ considerably. To leave no stone unturned in your quest for untroubled slumber, consider assessing your bedroom's fung shui which, according to fung shui master Au Chung-tak (tel: 2395 5077), can have an effect on your health as well as your sleep. 'A bedroom should be yin - restful and calm,' he says. 'If it is too yang, too busy, it might stress you out or wake you up, and give you a bad night's sleep.' You should, therefore, avoid having a television, desk, computer and exercise equipment in the room because they are symbols of activity and hamper sleep. If the objects have to be there, cover them up or store them away at night. 'Your health will suffer and your sleep be disturbed if you can see the front door when you lie on your bed - everyone comes in through the front door so you won't get enough privacy and will end up tired,' Au says. 'Don't have bright lights above your bedhead or plants or fish in your bedroom because all have too much active energy and will keep you awake. Lighting and decor should be soft to promote tranquil sleep.' A mirror near your bed is also bad for health and relationships, and the head of your bed should be against the wall to give you a sense of security. But don't panic: all such problems can be easily rectified by moving furniture or using strategically placed throws. If it sounds like a chore, take heart. At the end of the day, there is no better way to test out the fruits of your labour than to lie back and get some well-deserved sleep. 10 tips from the Better Sleep Council for punching out zeds Put away your 'to do' list and make sleep a priority. Unwind early in the evening, dealing with distracting tasks and worries several hours before bedtime. Develop a sleep ritual by doing the same things at the same time every night. It will programme your body. Milky drinks and warm baths will help you relax and feel sleepy. Keep regular hours by going to bed and waking up at the same time - even on weekends. Create a restful place to sleep. Buy a comfy, supportive mattress. Exercise regularly to get rid of stress and tension, but don't exercise just before going to bed. Cut down on stimulants, such as caffeine, and reduce your alcohol intake in the evening to avoid fragmented sleep. Don't smoke. Smokers apparently take longer to fall asleep and wake up more often during the night.