STEPHEN LEWIS marks National Bed Month by seeking a few tips on buying a comfortable bed.

WE spend up to a third of our lives in bed.

Over a 70-year lifespan, that's more than 200,000 hours.

That's a lot of time. Which makes it all the more surprising that most of us spend so little time and effort making sure we choose the right bed.

We spend hours deliberating over clothes, a new washing machine or what colour to paint the bedroom ceiling. But when it comes to buying the right bed, while we might spend time choosing one that will look good, it never seems to occur to us to bother about whether it will be comfortable or not.

"So many people stand at the end of the bed and just prod it with their finger," says Nick Wood, manager of MacDonalds (York) Ltd, the Fossgate furniture store.

"That's not enough. You need to actually get on the bed and try it! It can make all the difference to getting a good night's sleep."

The Sleep Council says that an uncomfortable bed can cost you on average up to 42 minutes sleep a night: enough to leave you feeling tired and bleary-eyed when you struggle into work.

So how do you go about choosing the right bed?

Sleep Council spokesperson Jessica Alexander says the key factors to consider are comfort and support. Too soft, and a bed will develop a hammock-like curve: too hard, and it will create pressure points. Both could leave you full of aches and pains when you wake up - and could lead to back problems in the future.

The softness or firmness of a bed, Jessica says, is a combination of the mattress and the bed itself.

Mattresses generally come in three grades: soft, medium and firm. There is no general standard, though - different manufacturers make mattresses of different firmnesses, so the key thing is, as Nick Wood says, to try out the bed in the shop.

As a general rule of thumb, Jessica says, the heavier you are, the firmer the mattress you need. If you're fairly light, up to 11 or 12 stone, you can get away with a soft mattress. If you weigh between about 12-16 stone, she says, you probably want to be looking at a medium mattresses. Any heavier and you really ought to be thinking about a firm one.

Individual tastes differ, though. There's nothing to prevent a lighter person going for a firmer mattress if you feel that's more comfortable - and if you're quite large, but prefer the feeling of a soft mattress, you can get mattresses with firm "cores" covered in softer layers. Ask the assistant for advice.

Don't forget, the bed base itself affects firmness. A slatted base makes the mattress a little firmer: a sprung base makes for a softer feel.

Whatever kind of bed or mattress you favour, do try it out properly first. Jessica recommends narrowing your selection down to three, and then spending a good five to ten minutes trying them out. Wear a pair of comfortable trousers, and lie in various different positions.

If it's a double bed, make sure your partner tries it out at the same time as you: because it's important you be able to sleep undisturbed. If one of you is much heavier than the other and you prefer different firmnesses of mattress, it may be worth considering a "zip and link" option, Jessica says - two separate bedsteads linked together, and two mattresses of different firmness that can be zipped together. That way you can create a double bed that has a different firmness for each partner. Again, ask your shop assistant for advice.

Ideally, when you're buying a new bed you should buy bed and mattress together. If you're buying a new mattress for a bed you already have, Jessica says, you should make sure that when you try it for size at the shop, you ask the assistant to put it on a bed similar to the one you have at home. Otherwise, when you get it home, it could feel quite different.

The other thing to consider when buying a bed, particularly a double, is size. "You need enough space so you can sleep undisturbed," Jessica says. If one partner is particularly tall, she says, they may often end up sleeping diagonally - leaving the smaller partner squashed into a corner of the bed. So if one of you is tall, it's worth considering a wider bed.

BED BUYING TIPS

Buying a bed is not a job to be rushed. Here are a few simple tips from the Sleep Council to help you:

- Try a selection of beds for comparison before buying

- Wear comfortable clothing and remove outdoor gear to try a bed

- Lie down in your normal position and make some turns

- Take your time - it takes more than five seconds to try a bed properly. Five minutes is better

- Try the bed together, if it's for two

- Don't forget, a bed is a base and a mattress together

- Think big. Larger beds are more comfortable.