Doctors say you had better use it before you lose it.The more you sit each day，the more chance you have of getting sick.

Richard Rosenkranz of Kansas State University is among the researchers.He says people who sit for long periods are at greater risk of some diseases when compared with those who sit less.He says that is especially true for some chronic diseases.

Richard Rosenkranz studied the relationship between sitting and chronic diseases in middle­aged Australian men.He worked with researchers from the University of Western Sydney.They studied the health records of more than 63,000 men from New South Wales.The men were between the ages of 45 and 65.The men reported about what diseases they had or did not have.And they kept a record of the amount of time that they sat each day.

The study also shows that exercising every morning for 30 minutes does not reduce the health risk if you spend the next eight hours sitting at a desk.Mr.Rosenkranz says it is important to make sure that you exercise.Also he says it is important to find ways not to sit so much during the day.

Many jobs today require sitting and working at a desk all day.James Levine works at the Mayo Clinic in the United States.He suggests working while standing at a high table some of the time instead of sitting at a desk.Dr.Levine also suggests standing while using the telephone or eating.And he notes that if you spend more time on your feet，you may have muscle activity that helps burn fat and sugar in your body.

1．at risk of有......的风险

2．compared with与......相比

3．chronic disease慢性疾病

4．require vt.要求

Period One　Welcome to the unit & Reading