Effects of 5-Minute Light-Intensity Physical Activity Breaks (Sit-Cycling and Stand-Twisting) on Cognitive Function, Sleepiness, and Back Pain in Physically Inactive University Students: Protocol for a Mixed-Design Laboratory Study.

backgroundUniversity students may remain sedentary for large parts of the day, spending >9 hours per day sitting. Prolonged sitting is associated with increased risk for adverse health outcomes in adulthood. Light-intensity physical activity (LIPA) can be integrated into university students' daily routines to counteract the negative effects of prolonged sitting on cognitive function and musculoskeletal health.

objectiveThis protocol describes a trial conducted in Singapore to evaluate the acute (immediate) and short-term delayed effects of two 5-minute LIPA modalities (sit-cycling [S-C] and stand-twisting [S-T]) on neurocognitive and somatic outcomes (prefrontal cortical oxygenation, cognitive performance, subjective sleepiness, and back pain) in physically inactive university students compared to a modality-matched passive control condition.

methodsThe study comprised a main study (N=22) and a methodological substudy (n=6, 27.3%). In the substudy, students' oxygen uptake was measured during 5-minute bouts of S-C and S-T to verify that both modalities meet the operational definition of LIPA. In the main study, physically inactive university students were allocated in a 1:1 ratio to either S-C or S-T (between-participant factor). Each participant completed two laboratory visits within their assigned modality: an experimental LIPA visit and a corresponding modality-matched passive control visit of equal duration (passive sitting for S-C and S-T), enabling within-person intervention-control comparisons. The primary endpoint is the change in bilateral dorsolateral prefrontal cortex (DLPFC) oxygenated hemoglobin (O2Hb) from baseline to immediately after the intervention during cognitive task performance (intervention vs control), measured with functional near-infrared spectroscopy (fNIRS). Secondary outcomes include O2Hb persistence at 20 minutes postintervention, cognitive performance (n-back test and Stroop Color and Word Test [SCWT]), subjective sleepiness, and back pain.

resultsThe study was funded by the Sendai University International Collaborative Research Grant in April 2023, and the trial was registered with ClinicalTrials.gov on November 21, 2024. Participant recruitment and data collection were completed in December 2024. The substudy results showed that both 5-minute S-C and S-T bouts fell within the LIPA range of <3 metabolic equivalents (METs) and could be implemented as brief, standardized LIPA breaks in the main trial. For the main trial, data cleaning and preliminary analyses are ongoing, and the outcomes will be reported in a subsequent outcomes paper (anticipated in late 2026).

conclusionsThis protocol provides a prespecified framework to test whether brief 5-minute LIPA bouts may be a practical strategy to interrupt prolonged sitting and acutely improve prefrontal oxygenation and related neurocognitive and somatic outcomes in physically inactive university students.

trial registrationClinicalTrials.gov NCT06703424; https://clinicaltrials.gov/study/NCT06703424. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/82510.