The benefits of exercise are well documented, but some are more relevant for older people. You can reduce the risk of heart disease and strokes, prevent or control high blood pressure, improve joint mobility and muscle strength (muscle strength, power, endurance and flexibility decrease with age), prevent osteoporosis... the list goes on. You may even lose weight.
So how to start if you've had years of sedentary living? You don't have to join a gym and become a Concept 2 fiend like Gerald Haigh. Keep it simple - and always remember that any activity is betterthan none. So while the ideal may be moderately intensive physical activity (like a brisk walk) for half an hour, five times a week, start off gently.
The official line is that to benefit your health, physical activity should be at an intensity that raises your heart rate enough to leave you breathing more heavily than usual and feeling warmer. This does not mean you have to jog for 20 minutes. Start slowly and build up gradually. Maybe on day one you could spend 10 minutes climbing the stairs, walking the dog an extra block, weeding the garden, even doing a spot of vigorous housework. It all counts. (You're doing too much if you can't talk while you're active.) Don't spend a fortune on lycra. All you need is something loose and comfortable and a strong pair of shoes with a cushioned sole to prevent jarring your joints. And remember, if you have any doubts - especially if you have high blood pressure, diabetes, arthritis, back trouble or other medical problems - check with your doctor first.