单选题 Fifty years ago, most people"s daily levels of activity were equivalent to walking three to five miles a day. Today, the 41 person fails to 42 that distance in a week. It"s 43 the ratio of fatness has soared—with serious implications for health.
What we have 44 in convenience from labour-saving devices over the past half-century, we have paid for 45 a sharp decline in physical activity. We use cars, buses or trains to 46 work; our children are 47 to school; elevators and lifts have replaced 48 stairs in shopping centres, offices and apartment blocks. Washing machines, vacuum cleaners, dishwashers and electric mowers all reduce the effort required to 49 a clean and tidy home. Almost one third of adults 50 over ten hours sitting down everyday, adding 51 a staggering average of 32 years and four months over a lifetime. 52 surprising, then, that researchers 53 this lifestyle for our weight gain.
Of course, our diets have changed, too, 54 the fact is we consume fewer calories now than in the 1960s. So what is the 55 ? The secret is integrated exercise. This 56 going about your normal daily life—but doing it with enthusiasm. It might mean standing to 57 the phone and tapping your feet on the floor as you work. It means never taking the car when you could walk; it means standing on short train and bus 58 , or walking at a pace 59 you feel you might break into a run if you were to go any 60 .