The objective of this randomised controlled trial is to examine the acute effects of two novel light intensity exercise (sit-cycling and stand-twisting) on prefrontal cortical blood oxygenation, executive functioning, sleepiness and back pain among inactive university students.

The main questions it aims to answer are:

• What are the changes in oxygenated haemoglobin (O2Hb) and deoxygenated hemoglobin (HHb) levels in the prefrontal cortex from baseline to immediately after and 20 minutes after a 5-min bout of S-C and S-T compared to sitting for the same duration?
• What are the changes in executive functioning, specifically, n-back test and Word Colour Stroop test performance from baseline to immediately after and 20 minutes after a bout of S-C and S-T compared to sitting for the same duration?
• How does participants' self-rated daytime sleepiness and back pain after a bout of S-C and S-T compare to sitting for the same duration?

Participants will:

• Perform sit-cycling or stand-twisting for 5 mins (experimental condition) and sit for 5 mins (control condition)
• Wear the functional near-infrared spectroscopy cap on their head throughout the measurements
• Complete 1-back, 2-back test and Word Colour Stroop before, immediately after and 20 minutes after experimental/ control condition
• Have their blood pressure, heart rate taken by a smartwatch
• Complete a daytime sleepiness questionnaire and a back pain questionnaire

Inclusion Criteria:

• NTU-NIE university student, between 21 and 30 years old, do not meet physical activity guidelines (150 mins of weekly MVPA)

Exclusion Criteria:

• taking blood-pressure lowering medication
• physically active (150 mins or more of weekly MVPA)
• deemed not physically fit to participate in physical activity based on responses to Get Active Questionnaire

Individual participant data constitute as personal data. Under the Singapore Personal Data Protection Act, it is mandatory that individually identifiable data are to be kept confidential.