More Americans are exercising but rates of obesity and smoking have not changed, according to the latest government data.

A survey by the U.S. Centers for Disease Control and Prevention released on Wednesday finds obesity rates were frozen last year at around 28 percent of adults compared to 2008.

But 34.7 percent claimed in 2009 they engage in regular leisure physical activity, up from 31.9 percent in 2008. And 39.8 percent said they had been tested for the AIDS virus, slightly more than 38.7 percent in 2008.

Health experts and the U.S. government both recommend getting daily exercise -- about an hour a day of moderate exercise for most adults -- to keep weight off and prevent heart disease, diabetes and cancer.

The CDC also recommends that every adult get an HIV test. The CDC estimates that about 1 million Americans are infected with the human immunodeficiency virus that causes AIDS, but more than 20 percent have not been tested and do not know it.

Some other facts from the CDC's National Center for Health Statistics:

* The prevalence of obesity among adults aged 20 and over has increased from 19.4 percent in 1997 to 28 percent in 2009.

* In 2009, 9 percent of adults 18 and over had diabetes, up from 8.2 percent in 2008 and 5 percent in 1997.

* 20.6 percent of adults smoked, about the same as in 2008.

* Nearly 23 percent of adults had at least one day of binge drinking in 2009, defined as having five or more drinks in a day.

* Most Americans believe they are healthy. More than 66 percent said they had excellent or very good health, down from 68.5 percent in 2008. 2.4 percent said they had poor health.

* Just over 4 percent of all Americans said they had an asthma attack in the past year.

(Editing by Cynthia Osterman)