If you are thinking about next year's marathon you should obtain specialist advice from your local running club or seek out information in running magazines. The marathon organisers will also help out. As a general guide:
* Have a health check.
* Build up to running a minimum of 20 minutes at least three times a week.
* Introduce a fourth session and start increasing the length of your weekend run. This should last an hour and combine running and walking. As your fitness increases, you should run more than you walk.
* Gradually lengthen at least two of your weekly sessions - and remember to include plenty of rest days - until your longest run is at least 15 miles. You should complete a three-hour run, three weeks before the big day.
* If you're feeling off, or are injured, don't train. And if it's just before race day, get a letter from your doctor and the London Marathon will grant you an automatic place the following year.
* Diet is important - watch what and when you eat.
* Whatever the agonies, there are benefits: you'll boost your cardiovascular fitness, increase your bone density and improve your muscle condition whatever your time.