Dr Benedict Tan, who heads the Changi Sports Medicine Centre at Changi General Hospital, gives a sample exercise prescription for someone who is 45, has high blood pressure and leads a sedentary lifestyle.

• Do 20 minutes of brisk walking three times a week.
• Progress to 30 minutes a session, and gradually raise the frequency to five times a week. This will add up to 150 minutes of physical activity a week.
• To build body strength, do exercises such as squats, lunges, push-ups, sit-ups or pull-ups twice a week. There's no hurry. Start after you get used to aerobic activities, for instance, three months after you begin doing aerobic exercises. Avoid holding your breath during the strengthening exercises.
• Stretch before and after strength and cardiovascular sessions.
• Accumulate 10,000 steps a day during activities of daily living. Such activities tend to be of a low intensity, and include walking to the car, doing housework and gardening. A city dweller takes an average of 3,500 steps a day.

The Health Promotion Board and the American College of Sports Medicine recommend 150 minutes of moderate-intensity physical activity a week, or 75 minutes of vigorous physical activity.

Research has shown that such levels are effective in reducing disease incidence and early death.