The later the school start time, the better the odds of high schoolers being rested and ready to learn, experts say.

And the St. Paul School District has taken notice.

District officials are considering pushing back high school and middle school start times from 7:30 to 8:30 a.m. beginning in the 2015-16 school year.

Such a move would require not just a reshuffling of start times, but of bus schedules, too. The series of changes are significant enough for the district to call for meetings with constituencies ranging from high school coaches to teachers to parents with children in the before- and after-school Discovery Club program.

On Thursday night, the district will take input from its Discovery Club community. The listening sessions will continue into September in hopes that the school board can vote in October on a start-times proposal for 2015-16. No changes are planned for this fall.

The reason for later starts is clear enough. Studies have shown high school students perform better if they sleep longer. In 2009, the South Washington County School District pushed back high school start times from 7:35 to 8:35 a.m. Test scores rose and car crashes involving teens declined, a recent University of ­Minnesota study showed.

But a later start also means a later end to the school day, which can complicate life for student athletes, especially in the spring, when outdoor games must be completed before dark, said Kerry Timmerman, principal of Park High in the South Washington County School District.

If a game is in Forest Lake, he said, kids have to leave school before sixth-hour ends. In most cases, that has been a trade-off worth making, he added, because students involved in extracurricular activities also tend to do better academically.

Said Timmerman, "We'd rather have them involved than not involved."

The idea of delaying school start times for teens is rooted in science. For teens, going to bed early to wake up early doesn't work because their bodies don't experience a natural shift into sleep until 11 p.m. — no matter when the start time might be.

In St. Paul, a potential challenge for elementary students and parents — if later starts are recommended and approved for secondary students — would be new 7:30 a.m. starts for elementary-level community schools and regional magnet schools. The majority of those students now start the day at 8:30 a.m.

As a result, some elementary students could be picked up at bus stops as early as 6:30 a.m., district officials say.

The district has noted, however, that there also is evidence suggesting elementary students benefit from earlier start times. They are more attentive and more likely to eat breakfast at school, officials say. A move to an earlier start also would allow the district to schedule core classes before lunch, "the best learning time," it says.

Cost is not a factor, ­officials say.

Ryan Vernosh, a district strategic planning and policy administrator, noted that the scenario now being discussed maintains the current three-tier busing structure, with start times at 7:30 a.m., 8:30 a.m. and 9:30 a.m., without any change in busing costs. A move to a single tier system could have cost an additional $35 million, he said.

But whether the district moves to the new plan, or sticks with what it has now, will depend in part on what the public has to say. And the district is prepared to listen, spokeswoman Toya Stewart Downey said last week.

The Discovery Club community is scheduled to meet at 6:30 p.m. Thursday at EXPO for Excellence Elementary, 540 Warwick St. S. The district also has created a start times webpage at www.spps.org/starttimes.

Anthony Lonetree • 651-925-5036