Differences in Cortisol Profiles of Students according to School Schedule

Abstract Background Matching school schedules to students’ attention spans positively impacts students’ health and performance. Cortisol measurement is a recurrent procedure to assess both the chronotype profile and to evaluate attention. Students circadian profile evolves as they age but often schools’ schedules ignore this fact. This research maps students cortisol profile across the week and school schedule. Methods The sample includes over 200 students (6 to 18 years of age), enrolled in primary schools or secondary (high) schools in the province of Valencia (Spain). Data was gathered between 2023 and 2025. The protocol is suited to both cross sectional and longitudinal research designs. In this paper we present a cross sectional analysis of the data due that the project is still ongoing. The cortisol protocol applied provides the daily curve for cortisol and establishes the better-fit saliva curve collection protocol for the standard cortisol pattern. The sampling (collection of saliva took place during execution of usual daily activities on Monday (M), Thursday (Th) and Sunday (Su), allowing assessment cortisol levels through the day and across the week. Results 591 samples analysed from 26 students following compact schedule (C) and 23 students following split schedule (S) in 5-point curves (1h, 4h, 9h, 11h and 13h after waking up) on M, Th and Su shows that: 1) The maximum cortisol concentration values are highest on M and lowest on Su. 2) There are differences in the C group: M1h>Th1h>Su1h. 3) There are differences in the S group: M1h>Su1h, Th1h>Su1h. 4) Inter-group statistical analysis shows higher 4h cortisol in S Th curve. Conclusions Significant intra-group differences indicate the presence of greater stress at the beginning of the week for the two groups. The behaviour observed in the Th curve seems to indicate that the stress present at the beginning of the week is more lasting in S than in C. Key messages • Organisation of the school is a key factor in the healthy development of school children. • School time organisation should adapt children's developmental needs and characteristics.