This cluster randomized trial is conducted in Beijing primary schools to evaluate the efficacy of a WeChat mini-program-based high-temperature early warning intervention on the physical and cognitive health of school-age children. Six participating schools are randomly assigned to two parallel groups. The intervention group receives tiered heat alerts and guided self-health monitoring via the mini-program. The control group follows standard daily school and family routines, with no dedicated digital high-temperature early-warning intervention. The primary outcome is children's executive function after a 2.5-month follow-up. A range of secondary indicators related to physical status, mental health and health behaviors are assessed concurrently to quantify the intervention's benefits in mitigating adverse health outcomes caused by high temperatures.

This pilot study is conducted in Beijing, with 6 primary schools selected as research sites. A stratified cluster randomized controlled design is adopted, with schools as the unit of randomization. Eligible primary schools are randomly assigned to the intervention group and the control group, with 3 schools in each group.

A total of 5 Wisconsin Card Sorting Tests (WCST), 2 health examinations, 2 children's high-temperature protection themed drawing activities, and 5 mini-program questionnaire surveys will be conducted in this study.

The intervention group receives a digital intervention of high-temperature health risk early warning. The research team uses a WeChat mini-program to release corresponding high-temperature health risk level information, health tips, protection science popularization information and other early warning content when the high-temperature health risk level reaches yellow, orange or red, and simultaneously pushes them to head teachers and parents.

The monitoring and survey schedule for the intervention group during the study period is as follows: at baseline and endpoint, unified offline WCST and health examinations will be conducted for children once each, accompanied by one online mini-program questionnaire survey each time. One children's high-temperature protection themed drawing activity will be organized at baseline and at the end of the 3rd month after the intervention, and the works will be uploaded to the mini-program for check-in. At the end of the 1st, 2nd and 3rd months after the intervention, one online follow-up questionnaire and WCST will be completed each month, together with check-in. Meanwhile, blood pressure will be monitored once a week, and daily blood pressure monitoring and check-in will be carried out after each high-temperature health risk early warning release. In addition, after the release of high-temperature health risk early warnings, the intervention group is required to complete check-in for reading and transmitting early warning information, health tips and protection science popularization content, as well as online mini-program surveys on children's awareness of high-temperature health risk early warning information and short-term behavioral patterns. The above WCST and questionnaire surveys will be completed by children with parental assistance; blood pressure monitoring and check-in are the responsibility of head teachers during non-summer vacations and parents during summer vacations.

The control group does not receive the high-temperature health risk early warning intervention and will only complete the corresponding WCST, health examinations, questionnaire surveys and blood pressure monitoring.

School inclusion criteria

1. Willing to participate in the study.
2. Possess adequate facilities and qualified teaching staff.
3. The school and teachers maintain good cooperation.
4. Class size is no less than 35 students.
5. All participating classrooms are equipped with air conditioners.

Participant inclusion criteria

1. Fourth-grade primary school students aged 9 to 11, of all genders.
2. Voluntary participation by students and their parents, good compliance, and signed informed consent.
3. At least one adult family member has an internet-enabled mobile device.
4. Good general health with no history of severe physical or mental disorders.
5. Local permanent residents with a residency of no less than 6 months.

Participant exclusion criteria

1. Participants who are unable or refuse to complete required examinations.
2. Students receiving psychological or psychiatric treatment that may confound the study results.
3. Those currently enrolled in other interventional clinical studies that may affect outcome assessment.
4. Any other conditions deemed ineligible by the research team. Any participant meeting any of the above exclusion criteria will be excluded from the study.