Austin — Texas public school students are startlingly unhealthy and their fitness levels decline sharply through 12th grade, where less than 10 percent of students passed a fitness test this year, according to the first results of an annual health assessment.

The most physically healthy class was third grade girls, of whom 32 percent were deemed physically fit according to a six-part measure of aerobic capacity, body composition, muscular strength, muscular endurance and flexibility.

But the number of physically fit students declined every year through high school, where just 7.8 percent of senior girls and 8.5 percent of senior boys reached the "Healthy Fitness Zone."

"These results just confirm what many of us already knew and that is that our children's health is in jeopardy," said Sen. Jane Nelson, a Lewisville Republican who pushed legislation requiring the fitness assessment last year. "We cannot allow an entire generation of Texans to grow up and live a shorter life than previous generations."

The new law requires a physical fitness assessment of all public school students beginning in third grade. The results are to be reported to the Texas Education Agency, which will analyze the results by school district annually, comparing results to students' grades, attendance, obesity, disciplinary problems and school meal programs. That data is expected to be available later this year.

The poor results in upper grades correspond with decreased physical fitness requirements in high school, said Texas Education Commissioner Robert Scott.

The new law also requires 30 minutes of daily "moderate to vigorous" physical activity, or 135 minutes a week, for children up to fifth grade. For students in sixth through eighth grades, 30 minutes a day, 125 minutes a week or 225 minutes over two weeks is required.

The Fitnessgram test, developed by aerobics pioneer Dr. Kenneth Cooper, includes a skin fold test, curl-ups and push-ups. Another exercise tests flexibility, with students sitting with one bent leg and one straight leg and then reaching forward as far as they can.

In the trunk lift, which tests trunk extensor strength, students lie on their stomachs and raise their upper body while the teacher measures the distance between the students' chins and the floor. The last test is called the pacer, a paced 20-meter run that increases in intensity as time progresses.

The results are recorded on a report card that allows parents and teachers to identify the physical strengths and weaknesses of each student. Results, unattached to students' names, also go to the TEA, which will compare the fitness data to students' grades, attendance, obesity, disciplinary problems and school meal programs.

Health experts say there is a correlation between physical fitness and good grades and Cooper called exercise "fertilizer for the brain."

"If you want to increase grades in school, get your kids in shape," he said.

"Clearly, we need to make sure our children are more active," Scott said. "But schools can't do this alone. We need to work with parents and communities and we need to make sure our children achieve a more healthy lifestyle."

Forty-two percent of the state's fourth-graders, 39 percent of eighth-graders and 36 percent of 11th-graders are overweight or at risk of being overweight, according to a 2007 report from the Texas comptroller. Overweight people have increased risk for adult heart disease and diabetes and lower life expectancy.

More than 8,000 Texas schools participated in the Fitnessgram test.