If you want to look good and feel great whatever your age, being physically fit and active is the answer. Staying active can ward off a great deal of the ageing process, such as loss of bone density, flexibility, strength, stamina and mobility. Women who train regularly can have better bone density at 60 than women half their age who are physically inactive.

You don't need expensive equipment or a punishing gym schedule to beat the clock. Building healthy activities into your daily routine is easy and it is never too late – or too soon – to start. 'The younger you start the longer you'll reap the benefits for,' says personal trainer Chris Fitzgerald. 'Doing it at 20 is like money in the bank for when you are older.'

All it takes is 30 minutes of moderately strenuous activity a day. The ideal level of exertion leaves you breathing more heavily than normal, but still able to hold a conversation, and warm and slightly flushed, rather than gasping for air and running with sweat. Any physical pursuit that keeps your heart rate up for half an hour is applicable and, yes, that does include nocturnal activities.

Sex isn't the only fun thing that's good for you: clubbing is too. Dancing is superb all-round exercise, and clubbing or doing a salsa class once a week is a great start to an activity-based routine. (Shopping only counts if it includes a 30-minute brisk walk.)

When planning for a more active you, make sure you pick things you enjoy doing. That way you are far more likely to keep to the plan, and the hormones you release when you're happy have long-term health benefits.

Get active with your mates. Exercise is much more fun with a friend and it can be a great way to catch up. Suggest going for an after-work swim or a Saturday-afternoon walk and you can natter away while you're keeping fit. If you are any good at sports, such as squash, tennis and badminton, so much the better, although the chat will have to wait until afterwards. Having a regular date with someone will also help to keep you motivated to continue. Make use of what you've got – if you've got dogs or sprogs, run around the park with them.

Every activity requires an amount of effort, but some take more than others. Going to the gym or the pool requires you to drag yourself out of the house first, but following an exercise video doesn't. Choose a few from the dozens on the market and do a different one weekly. Failing that, half an hour's gyrating around your living room to your favourite dance music is always good for a laugh. There are also endless books with 20- and 30-minute home workouts using little or no equipment.

Your daily activity should include 10 to 15 minutes of weight-bearing exercise to strengthen muscles and bones. Weight-bearing or resistance exercise means activity where the body is carrying its own weight, so walking, running, squats, press-ups and crunches are weight bearing, whereas cycling and swimming are not, because the body is supported.

Setting time aside for exercise can be a bind, especially at the beginning, so make use of the opportunities that already exist in your usual routine. Ban lifts from your life and always walk up escalators; climbing stairs is great weight-bearing exercise and especially good for the bottom and thighs. Take every opportunity to walk - don't call a cab or hop on public transport for a half-mile journey, and walk briskly, don't amble. Set the pace by imagining you are late for work. Be more dynamic about doing the housework and put some effort into it. Gardening is also terrific exercise.

Staying active to stay young doesn't just apply to the body. The brain is like any other muscle: if you don't use it, you lose it. The best way to keep your mind in good health is to exercise it. Philip Hodson, a fellow of the British Association for Counselling and Psychotherapy, recommends crosswords, word puzzles, games and practising a musical instrument. Being around younger people and keeping in touch with their culture and influences helps you stay young, as does having a positive attitude to life.

If you want to remain a strong, independent woman rather than become a frail little old lady, get moving and keep moving, mentally and physically.