As I get older, is it possible to be "too active"? As an older person, is there anything special I need to take into consideration?
Priya Vincent, by email

The body's response to physical training changes with age. Two scenarios should be considered: the person who has always been active, and the previously inactive person who discovers sport when older (or takes it up again after a long break).

In the first instance, studies on both endurance and strength athletes have shown that it is possible to delay the ageing process. Nevertheless, ageing catches up. Inevitably, sporting performance will decline, though the ability to perform high-level physical work will stay higher than sedentary age-matched peers. This trend of remaining active until very late in life is welcome: its popularity is witnessed by, for example, the Masters Olympic Games, a tournament reserved for competition between older athletes.

If one starts from scratch in middle or late middle age, then the usual recommendations apply: too much too soon, too long, too intensely will never be too good, and check with your doctor before embarking on any programme. Graduality and constancy are the name of the game. For recreational athletes and keep-fit enthusiasts, the multilaterality concept should be applied: a different activity every day of the week. In this fashion, different parts of our body and different systems are stimulated, and various motor and dexterity skills are acquired.

In any case, the spectre of overdoing it is always present. Our body needs time to adapt. While training is fun, done to extremes it can cause damage. A rule of thumb is to start with vigorous exercise for 30 minutes three times a week, and progress by 5-10% every week. Remember: we learn how much is enough from how much was too much.

·Professor Maffulli is a consultant orthopaedic and sports injury surgeon at Keele University medical school. If you have a question for him, email fitness@theguardian.com