Sleep, Mental Fatigue, and Performance in Students

Study overview

This is a prospective, observational, within-subject, repeated-measures, naturalistic case-crossover study involving physiotherapy and psychology students at LUDES Institute. The study focuses on how real-world academic demands (lectures and exams) interact with sleep, circadian rhythms, and mental fatigue to influence cognitive and physical performance. Each participant serves as their own control across three conditions: a baseline week without formal classes or exams, a typical theoretical class day, and, where applicable, an exam day.

The project is categorized as Category A (minimal risk and burden) under Swiss human research legislation and will be conducted in accordance with the Declaration of Helsinki, ICH-GCP (International Council for Harmonisation Good Clinical Practice), and applicable Swiss laws and guidelines.

Study objectives and hypotheses

The central objective is to characterize the psychobiological responses of physiotherapy and psychology students under varying academic pressures and schedules.

The study aims to:

Quantify changes in subjective mental fatigue, sleepiness, motivation, and objective cognitive and physical performance from before to after lectures and exams.

Evaluate how sustained cognitive demand across the university day affects psychomotor vigilance, executive control, and handgrip endurance.

Determine how sleep quantity and quality, as well as chronotype and time of day, moderate these responses.

Explore how the interaction between chronotype and timing of classes/exams relates to academic performance (exam grades) and perceived stress.

Key hypotheses include:

Longer classes and exam sessions will be associated with greater increases in mental fatigue, perceived effort, and sleepiness, and with reduced motivation and executive performance post-session; physical capacity is expected to show smaller decrements.

Students with sleep efficiency above 85% and nightly sleep duration above 7 hours will show greater resilience to mental fatigue, maintaining more stable reaction times and better cognitive performance than those with shorter or poorer-quality sleep.

Evening-type students will perform worse and feel sleepier during morning sessions compared with morning-type students, independently of total sleep duration, reflecting a chronotype × time-of-day interaction.

Mental fatigue will strongly impair cognitive tasks, while physical capacity (handgrip) will show relatively smaller declines.

Study design

The study uses a prospective, within-subject repeated-measures design with three main observation windows (T0, T1, T2).

Baseline/familiarization (T0):

A control week with no formal academic demands (no classes or exams). During this week, baseline psychometric, behavioral, and sleep profiles are collected, including overall sleep quality over the past 30 days and chronotype. Participants complete the Pittsburgh Sleep Quality Index (PSQI) and Morningness-Eveningness Questionnaire (MEQ), provide demographic and lifestyle information (e.g., caffeine use, napping, fitness), and undergo baseline assessments of mental fatigue, sleepiness, motivation, cognitive performance, and handgrip strength and endurance.

Class condition (T1):

A regular theoretical lecture session is used as the exposure. Pre- and post-class assessments are conducted in both morning and afternoon sessions (ideally before 09:00 and after 13:00 for morning, before 14:00 and after 17:00 for afternoon). The same battery as at baseline is administered, with added measurement of class duration.

Exam condition (T2):

An exam session, when feasible based on each student's timetable, is used as a high-stakes exposure. Pre- and post-exam measures parallel those in the class condition. Exam grades are collected as an indicator of academic achievement.

Across all conditions, assessments are scheduled twice in the morning and twice in the afternoon, yielding multiple pre/post evaluations per participant.

Study population and eligibility

Participants are physiotherapy and psychology students at LUDES Institute. The target sample size is 30 students, with an expected dropout of 10-15% after the start of experimental procedures.

Inclusion criteria:

Enrolled physiotherapy or psychology student at LUDES Institute, age 18 years or older, no self-reported major neurological disorders or conditions that would impair cognitive or physical testing.

Exclusion criteria (relevant to the specific study sessions):

Use of psychostimulants (e.g., caffeine, energy drinks) before or during scheduled study sessions, vigorous exercise prior to testing sessions, melatonin intake, recent travel involving more than 3 time zones or shift/part-time shift work, self-reported clinical sleep disorders, absence from more than 25% of total scheduled lesson time.

Recruitment and informed consent

Recruitment and screening are coordinated by the project leader and the DIMUSCHEL research team. Students are initially informed about the study at the end of a class by a member of the research staff. Those who express interest receive more detailed information in person. After verbal agreement, students are given an information sheet and a consent form (pre-signed by the project leader and provided in duplicate). They are allowed sufficient time to read, ask questions, and decide whether to participate.

Participation is voluntary, and students may withdraw at any time without consequences. No financial compensation is offered. Signed consent forms are collected and retained as part of the study records.

Interventions and procedures

This is an observational study with no experimental therapeutic intervention. The "procedures" consist of non-invasive questionnaires, cognitive tasks, physical tests, and sleep monitoring.

Cognitive assessments

Stroop task (Encephalapp):

A tablet-based Stroop task is administered in two modes: congruent (Stroop "off") and incongruent (Stroop "on"). In the congruent condition, participants identify the color of pound signs displayed in different colors; in the incongruent condition, they identify the font color of color words presented in mismatched ink (e.g., the word "green" printed in blue). The test includes six phases per condition, with approximately 60 trials in each condition. Response time (latency for correct responses) and accuracy (number of correct responses) are recorded, and results are averaged across trials. Each Stroop assessment takes about 5 minutes.

Subjective states (mental fatigue, sleepiness, effort, motivation)

Visual Analogue Scale for Mental Fatigue (VAS-MF):

• Sleepiness [Time frame: Pre- and post-session during teaching (T1) and exam (T2) sessions; also assessed at sleep/wake points during the monitoring period (the week in which T0 occurs).]
• Motivation [Time frame: Pre- and post-session during each baseline (T0), teaching (T1), and exam (T2) assessment.]
• Physical performance: handgrip strength [Time frame: Pre- and post-session during each baseline (T0), teaching (T1), and exam (T2) assessment.]
• Physical performance: handgrip endurance [Time frame: Pre- and post-session during each baseline (T0), teaching (T1), and exam (T2) assessment.]
• Perceived exertion [Time frame: During each handgrip endurance test (pre- and post-session) at baseline (T0), teaching (T1), and exam (T2) sessions.]
• Bedtime, wake time, time in bed, sleep onset, and sleep offset [Time frame: Five consecutive nights at the week in which the baseline (T0) occurs; three nights before and two nights after the teaching (T1) session; three nights before and two nights after the exam (T2) session.]
• Sleep efficiency and fragmentation index [Time frame: Five consecutive nights at the week in which the baseline (T0) occurs; three nights before and two nights after the teaching (T1) session; three nights before and two nights after the exam (T2) session.]
• Sleep latency, wake after sleep onset, total sleep time, immobility time, naps, and nocturnal awakenings [Time frame: Five consecutive nights at the week in which the baseline (T0) occurs; three nights before and two nights after the teaching (T1) session; three nights before and two nights after the exam (T2) session.]
• Chronotype [Time frame: At the week in which occurs the baseline (T0).]
• Sleep quality [Time frame: At baseline (T0) referring to the previous month.]
• Academic achievement [Time frame: At the exam (T2) session.]