The purpose of sleep is to make us effective during daylight hours. Whether you consider yourself to be a good sleeper, or you struggle to get a good night's rest – it's important to realise the full potential of your nightly sleep. Here are several ways of changing your daytime habits to improve your sleep at night …

Take physical exercise

Many of us spend much of our day sitting motionless in front of a computer screen, but research has shown that people who are physically fit and active have a better quality of sleep. Exercising just three times a week for 20-30 minutes will have a noticeable impact on the quality of your sleep, as well as your overall fitness. You should prioritise exercise that gets your heart pumping, such as walking, swimming or cycling.

However, be careful to avoid strenuous exercise in the evening and certainly just before bedtime. Exercise temporarily arouses the nervous system and therefore, taken late in the day, it can lead to problems in achieving and maintaining sleep. Exhausting yourself and then collapsing into bed is not a good strategy.

Eat a balanced diet

We all know that our eating habits are closely related to our health. So it won't come as a surprise that maintaining a balanced diet and a healthy weight will have a positive impact on your sleep. Heavy people are more likely to snore, and are at greater risk of developing conditions such as sleep apnoea. But rapid weight loss can also interrupt our sleep – if you diet too severely, hunger will occur at unusual times, which can wake you up. If you're on a diet, aim to lose no more than a couple of pounds a week.

When you eat is also important. Your main evening meal should not be within three hours of bedtime, to give your digestive system a chance to work. But don't go to bed on a completely empty stomach either. A light snack an hour or two before bed is fine.

Curb your caffeine intake

Caffeine is a stimulant, so called because it stimulates your nervous system, and too much of it can keep you awake. We all know that caffeine is found in coffee and tea, but you may be surprised at how many other products also contain it. Chocolate, soft drinks, headache pills and slimming pills may all contain caffeine. Check the label and avoid consuming any caffeine in the six hours before bedtime. If you want a hot drink in the evening try a decaffeinated version of your usual drink, or a mug of warm milk.

Restrict tobacco after dark

Nicotine stimulates the central nervous system, and makes it harder to fall asleep and stay asleep. Smokers are less healthy than non-smokers, and are therefore generally prone to sleep problems. Try to cut down in the evening before you go to bed, and try not to smoke if you wake during the night. Cravings for a cigarette are bad enough during the day; you don't want to develop them during the night too.

Avoid alcohol

Unlike caffeine and nicotine, alcohol is a depressant. It may help you fall into a deep sleep at the beginning of the night but, as your body absorbs alcohol, mild withdrawal symptoms occur that may wake you up or put you into a lighter form of sleep. Alcohol also causes dehydration and, as well as needing to go to the toilet more often, you may wake up thirsty. The best advice is to avoid alcohol four hours before bedtime. You should also avoid getting into the habit of having a night-cap. This can very quickly encourage dependence on alcohol to fall asleep.

Store your sleep

It is the natural order to have spells of activity and spells of rest, and some people swear by the restorative power of a daytime nap. As a general rule you should save your sleep for night-time and avoid napping during the day, but you can still rest your body and mind at intervals throughout the day to allow your muscles to replenish and your concentration to improve without actually sleeping. However, if you do feel sleepy during the daytime (rather than just tired) this may be dangerous. In these circumstances, a nap of 10-15 minutes is the sensible course of action.

Make a list

Many of us have busy lives and, while we all need a challenge, feeling overwhelmed is a recipe for stress. By extension, this may well affect our sleep. This is why managing your tasks effectively during the day can help reduce the worry at night when you are trying to sleep. Make sure that what you are taking on is realistic and achievable. Many people find writing task lists helpful. A list forces you to be specific and selective, and to make a practical plan of action. Then, when you find yourself lying in bed, thinking about problems, remind yourself that you have a plan of action in place already, to be dealt with when you're most capable of solving problems – wide awake, in the cold light of day.

The very fact that it's the norm to have dedicated bedrooms in our homes indicates just what a priority sleep is to us. Whereas the other rooms in our homes are where we enjoy relaxed wakefulness, the bedroom is where we should anticipate having good quality sleep. As such, we should do what we can to make it a sleep-friendly environment. It's important to consider the following arrangements that are likely to support good quality sleep …

Invest in your bed

Would you spend more on a flat-screen TV than you would be prepared to spend on a bed? Would you replace your mobile phone more often than your mattress? If so, what does that tell you? A bed is one of those things in life where you get what you pay for, and, as you'd expect, the quality of your bedding has a huge impact on the quality of your sleep. But beds and bedding are often not an area that we consider worthy of investment.

Personal preferences play a large part in what bedding is right for any individual. In many cases people tend to stick with their existing habits, rather than explore the options. Go to a department store and try out different beds. You may think you need two pillows, but perhaps no pillows is right for you. You might need a thick duvet to get a good night's rest, or perhaps just a sheet would suit you better. The key here is to experiment.

Turn out the light

Your bedroom should not be brightly lit, even before bedtime, and a combination of summer nights or strong street lighting and thin curtains should be avoided. Our brain responds to the dark by preparing us for sleep, so your bedroom should be very dark once you have switched off the light. The simplest solution is to have thick curtains or blinds. Some people sleep well with a sleep mask on, but this is not for everyone. If you prefer to have a bit of light, try to keep it at a very low level, like a small lamp in the hallway with the door ajar very slightly, or a plug-in night-light of minimal wattage.

Let the room breathe

A stuffy room is likely to cause an uncomfortable sleep, while fresh air will promote sleep. Try opening a window before going to bed– the circulation of good-quality air is going to be helpful. See what you can do to adjust that blend of temperature and air control so that it is right for you.

Optimum temperature

Extreme temperatures at either end of the range can affect our sleep. A room that is too hot (usually more than 24C) can cause restlessness. On the other hand, a room that is too cold (less than 12C) can make it difficult to get to sleep and can cause more unpleasant and emotional dreams. The ideal bedroom temperature is likely to be around 18C.

Banish noise

Noise is a well-known enemy of sleep – though people get used to some noises after a while. Living in a house close to a railway line, a ticking clock, or even a partner's snoring can all become quite familiar. It's worthwhile identifying any noises in your home environment that may be interfering with your sleep, and doing what you can about them.

Many noises, however, are out of our control. To deal with these you can try sleeping with earplugs, although many people find them uncomfortable. An alternative is to use a technique such as imagery to distract yourself from such noises.

Sharing your bed

For those of us who sleep with a partner it's important to consider the needs of two people when you are trying to get the best quality sleep. Simple compromises by one party – so simple that they seem petty – can have a large effect on the other's quality of sleep.

We can disturb each other's sleep in several ways, such as one partner reading in bed, coming to bed later or getting up earlier, as well as turning over during the night and periods of awakening. It's well worth talking about which of your partner's behaviours affect your sleep – they may be very simple to change.

Sharing your home

Beyond who we share our bed or bedroom with, our sleep can be affected by the schedules and habits of other family members. If you have young children there is little to be done about the disruption you are almost certain to experience, since this is a natural part of parenthood. However, you may still find the relaxation techniques overleaf useful in getting back to sleep quickly once you have been woken.

Older children in their teenage years may come and go at unsocial hours, and it is worth considering that we all differ in our natural daily cycles of sleep and wakefulness. In every situation, tolerance and compromise are often the best solution. Don't forget that it's good to talk. Simple rules of conduct agreed by all can be remarkably effective in improving your sleeping environment.

How often have you found yourself lying in bed thinking: "If only I could relax, I'd be able to sleep"? Well, there has to be truth in that. A relaxed state, physically and mentally, is certainly a prerequisite for sleep, and we know that naturally relaxed people are usually better sleepers.

Relaxation at bedtime and in bed is crucial, but sleep is not something that can be forced because it is a process of "de-arousal" or "letting go". Fortunately, learning to relax is a general skill and it is possible to learn to relax, even if you're not very good at it just now. It can help in a number of circumstances to take a less anxious approach. Being able to relax is great preparation for sleep, but it's also a great asset for day–to–day life too.

What is relaxation?

First of all you need to know what relaxation is. The human relaxation response involves both physiological and mental changes. Physiologically, relaxation is associated with deeper and slower breathing, a reduction in "muscle tone" (reduced tension) and a lowering of the heart rate. At the cognitive or mental level, relaxation involves detachment from the immediate external world, a focus on pleasant sensations or experiences, and a reduction of mental effort and anxiety.

Your first step in becoming more relaxed is to ask yourself whether you could benefit from improving your ability to relax – your natural "relaxation response".

Why is relaxation important?

Some people are better at relaxing than others; they seem to be able to do it quickly and naturally. Others face the challenge of learning to relax, but all of us could improve our relaxation skills. It matters to know how to relax because stress affects us biologically and psychologically, and an ability to relax helps us to handle stress and to maximise our productivity. It's not just major life stresses here either – it's also the daily hassles that are part of everyday experience. The relaxation response is the flip side of the stress response coin.

Learning to value relaxation

Do you think it's important to relax? People who don't value relaxation don't spend time on it. They might say it's important, but in their behaviour, you would never know. Our lives can be full of shoulds, musts and ought-tos, and we often don't give ourselves permission to relax. We might even feel that we shouldn't relax because there are "things that need to be done". Does any of this sound familiar? If so, your challenge is learning a value system. We are not designed to be on the go 24 hours a day.

General ways to relax

Whereas it's true that people relax in different ways, there are four essential types of relaxation response. There is the relaxation response that you get from active physical pursuits – "burning up" physical stress through activities such as exercise. Then there are active mental tasks such as playing chess to address mental stress. Then there is passive relaxation, which is more like "letting go", for example physically by having a bath or mentally by listening to music. Of course, there is no hard and fast distinction between active and passive, or physical and mental, but good sleepers are better than poor sleepers at the passive approach to relaxation.

Specific relaxation techniques

There are two specific techniques that have been shown to help get your mind and body into a relaxed state, ready for sleep. Progressive muscle relaxation involves the systematic tensing and deep relaxation of your body's major muscle groups, leading to a decrease in muscle activity, blood pressure and heart rate.

Imagery training is focused more on mental tension, and involves immersing yourself in a pleasant visual scene and heightening sensory awareness, leading to improved control of your mind and an ability to distract your thinking. Both relaxation techniques also include focusing on perceptions of heaviness and deep breathing associated with letting go, and take 10-12 minutes to complete. Practice is very important so that you get to know the exercises and can use them whenever you need them.

Which technique will help you?

Imagery training is more focused on mental tension, and since it involves no physical movement it is particularly well suited to those with muscular pains or cramps or with joint problems. Progressive relaxation is effective in relieving physical as well as mental tension. But by trying both techniques you can make up your own mind which one suits you best. Over time you will be able to see which is more effective for you.

However, a word of advice; do try them both and stick at them for a little while. If one or the other comes more naturally, that could mean it's the one for you; but also bear in mind that the more difficult one might indicate that this is the type of relaxation you need to spend a bit of time mastering. If you don't experience any difficulties, then maybe you could become skilled in using both techniques.

The following excerpts will give you an idea of what each technique involves …

1 Progressive muscle relaxation

" … Turn your attention to your arms and hands. Create some tension in your hands and arms by pressing your fingers into the palms of your hands and making fists. Do that with both hands now. Feel the tension in your hands, feel the tension in your fingers and your wrists, feel the tension in your forearms. Notice what it is like. Keep it going … and now relax. Let those hands flop. Let them do whatever they want to do; just let them relax. Breathing slowly and deeply, you will find that your fingers will just straighten out and flop, and your hands and arms will feel more relaxed. Allow them to sink into the bed; just allow your arms to be heavy. Breathing slowly and deeply, thinking the word ''relax'' each time you breathe out, and finding that your hands and arms just relax more and more and more. Your arms and your hands are so heavy and rested. It's almost as if you couldn't be bothered to move them. Let go of the energy and tension that was in the muscles there, breathing slowly and deeply. Both your hands, both your arms, heavy and rested and relaxed … "

2 Imagery training

" … Keeping your eyes gently closed, concentrate on picturing a pleasant scene. Picture yourself standing on a grassy slope. Look down at your feet – there is green grass all around you, the kind that grows well in the summer months. It looks thick and strong – it looks healthy. Just ahead of you, you will see there is the beginning of a path, and as you look down that path, you can see it winds down through some bushes, to a beautiful sandy beach, and beyond to the sea, a deep, clear blue. You can see the contrasts of all these colours, the rich green of the grass, the pale brown of the path, the yellow gold of the sand, and the deep blue of the sea. And as you stand on that grassy slope, as you look around you, you feel the breeze, warm and gentle on your cheek, and you feel the sun on your head, warming the back of your neck. It is a beautiful morning … "