• Half-hour blocks of exercise once or twice a week will maintain our independence
• Just two and a half hours of moderate exercise a week will keep us in the best of health.

In addition, we all need at least an hour a day of pottering about in our own homes and gardens, and ideally walking to the shops, to maintain a basic level of fitness.

There is more exercise value than we realise in being on our feet (prevents bone loss), going up and down stairs and lifting (maintains strength), doing housework, gardening and DIY (helps balance, flexibility and cardiovascular fitness).

Moderate exercise

'Moderate exercise' makes us warm and slightly breathless. It should be progressive - challenging us to do a bit more each time. We don't need to do two and a half hours of moderate exercise in one go, breaking it up into five half-hour sessions is best.

If you are very athletic it is important not to over-exercise. Older muscle is less efficient at repairing itself and damaged muscles may never recover.

If you are heading for the hills and are unused to them, build up muscle strength gradually by brisk walking on the flat first. By far the most damaging form of exercise is running downhill, when the muscles are used as brakes: unless you have done this most of your life, avoid running down mountains or very steep hills. Even walking down a steep hill should be done carefully.

Remember, avoid exercise if you are unwell, particularly if you have a significant infection - you may damage your muscles. Don't immobilise yourself during illness however - it's vital to keep moving about to avoid the risk of thrombosis and muscle wasting. Gentle pottering in your own home is the most you should attempt until you are fully recovered.

The important thing is to do what you can - any exercise is better than none at all. Aim to be more active, more often.