St. Paul teens get the long-awaited chance to sleep longer when a new school year begins this week, but the trade-off will require special attention, too.

Twenty-one elementary schools with nearly 10,000 students will start school an hour earlier — at 7:30 a.m. — in order to let the big kids occupy their old 8:30 a.m. start-time slot.

For the younger kids and their parents, the change will take some getting used to.

At Horace Mann School in Highland Park, a mom is worried about her fifth-grade daughter leading a school patrol line in the dark. At St. Anthony Park Elementary, a dad is anxious to see his kindergartner move up on an after-school Discovery Club waiting list that as of Friday totaled 27 students.

Elementary parents who in 2016 signed a petition opposing the 7:30 a.m. starts still have little good to say about it. Some have pulled their children from a district that can ill afford to see its enrollment numbers continue to slide.

On the other hand: A Como Park couple that had the opportunity to open-enroll two children in Rose­ville Area Schools decided against it out of loyalty to St. Paul. But the family is uncertain whether to continue when the youngest children reach kindergarten.

“We will stick for a year and see how it goes,” said Arielle Steingraber, who now has a third- and a fifth-grader at St. Anthony Park. “My kids aren’t the best with bedtime.”

Flipping the order for when older and younger children go to school means older students won’t be at home waiting for their younger siblings after school. That has increased demand for after-school care. The district responded this summer by making a flood of new hires to open up 360 new Discovery Club child-care slots.

Last week, the transportation staff finished tweaking the district’s bus stop locations to put some nearer to homes that have kindergarten kids — something it always has done but has taken on greater importance this year. Patrol officers, too, can expect to be reminded at roll call in the coming weeks that it now is the school district’s youngest kids who are out catching buses and walking the streets during the early morning hours, police spokesman Sgt. Mike Ernster said.

As for the potential hit to enrollment, Jackie Turner, the district’s chief operations officer, said she is encouraged by what she is seeing at the kindergarten level. She added it was too early to say whether the new start times will negatively affect grades one through five.

But she did note some charter schools and Minneapolis elementary schools have start times in the 7 o’clock hour.

“Seven-thirty is not new to the region,” Turner said.

Taking hold

In recent years, the Wayzata and Mounds View school districts have pushed back their high school start times. This week, Inver Grove Heights will join St. Paul among this year’s converts — with its secondary schools starting at 8:30 a.m. and elementary schools at 7:50 a.m.

Teens benefit from later starts because of the way their brains are wired. Going to bed early to wake up early doesn’t work because their bodies don’t shift into sleep until 11 p.m., research shows. So, the later the start, the better the likelihood they are rested and ready to learn.

Changes have paid off: Nationally, only one district that pushed back secondary school start times reversed course later. That’s out of 800 to 1,000 schools, itself a conservative estimate, said Kyla Wahlstrom, a University of Minnesota senior research fellow whose studies have helped power the national movement to align school starts to teenage body rhythms.

She notes that younger kids, on the other hand, have no trouble, biologically, with going to bed early and waking up early.

Going to bed early, however, can carve into family time, and that led Melissa Hickman, a Macalester-Groveland parent, to seize on the chance a year ago to pull her children out of the St. Paul district and put them in Great River School, a St. Paul Montessori charter school that starts at 8:30 a.m., she said.

Paolo Provenzano, a parent who organized the 2016 petition opposing the St. Paul changes, said he’ll be interested to see if enrollment tumbles.

“They’ll have to answer for it in the elections,” he said of school board members.

Jessica Kopp, who is running for school board this year, spoke in opposition to the elementary shift two years ago because she feared it would hurt low-income families. Her daughter now is headed to middle school, but she still has been hearing from Hamline Elementary parents weighing whether to keep their children there with a new 7:30 a.m. start.

“They feel terrible because they love the school,” she said. “But the impact on their family budget and their family schedule — they just can’t do it.”

Amber Waldo, a mom who had been concerned about potential increased costs to parents, said she believed the district ended up being fairer and more equitable with the changes. She also said that she was pleased to see middle school students moving into the 8:30 a.m. slot along with the high schoolers.

Wahlstrom said that “there are just no two ways about it,” change is hard, and it could take St. Paul families a full year to adjust.

In 1997-98, she studied start-time changes in the Minneapolis Public Schools and found that elementary students who had been moved to an earlier 7:40 a.m. start were seen by staff members as being more on task and focused, and less likely to act up in the afternoon.

Wahlstrom added that studies continue to point to teens benefiting and younger children showing no negative effects of start-time changes similar to the ones St. Paul is making. And as is the case with older students, there has been no clamor elsewhere to go back to the way things were for the youngsters. She would have heard, she said.