Hypothermia means "low heat" – deep body temperature has fallen below 95°F (35°C). The effects range from unpleasant to fatal – it's estimated that around 30,000 people die of cold-related causes in the UK every winter (including flu and other bugs).
You are most at risk if you can't move around much. Babies, and the elderly (because the body's has a harder time keeeping a constant internal temperature as we get older) are obviously at risk. But if you get wet in freezing conditions, get stuck in your car in a snowdrift, or your home heating breaks down, you can be at risk even if you're young and fit.

How do you know if there's a problem?

• In the early stages, you may just feel slightly groggy (even if you haven't had a drink) and be shivery
• If things get worse, violent shivers, slow pulse and being unable to think straight come next.
• Someone who is in serious trouble stops shivering, loses consciousness and seems to have little or no pulse. If they're not helped fast, they die.

What can you do if it happens?

The crucial steps are:

• get into shelter if you're outside – but if you're in a car, make sure you have some ventilation while the engine's running, or you could suffocate.
• change out of ALL wet clothing (including your underwear if necessary).
• have something to eat and a warm drink. The bad news is: that old standby, the brandy carried by St Bernard dogs in mountain rescues, is NOT a good idea.

Helping other people

A really effective way, if you are warm yourself, is to hug the cold person. The buzz word for this is “Kangaroo care” – how kangaroos carry their babies, right?
The other top solutions are to apply those crucial steps, and if necessary get the person to a professional as soon as possible. You need to be VERY careful about rubbing the cold bits – if the person has frostbite, you could do a lot of damage.

The bottom line

Prevention is MUCH better than cure. If it's cold, don't go out unless you have to; keep your home warm, especially if there's a baby around – and if cost is a problem, keep ONE room properly warm and move the baby's crib or the old person's bed into it for the time being. If you do have to go out, there are plenty of ways you can make sure you don't get into trouble – more on this another day. And if you like to be entertained while you learn, there's a brilliant description of the best way to cope with cold after a vehicle accident in Dick Francis's novel Longshot.