The treatment group will individually perform single-session Baduanjin by following a video broadcasted the standardised BDJ protocol, which lasted for 12 minutes including 6 times of BDJ movements. Breathing rhythm is emphasised to be followed by participants.

Verbal fluency task (VFT). Executive functions are measured using the VFT. The experimental design of this task is adapted from previous fNIRS studies of verbal fluency where task blocks were interleaved with control blocks. Participants are required to generate exemplars of two semantic categories (i.e., animal and means of transportation) as many as possible, each for one minute, during the task blocks. This experimental task will begin with a 30-second phrase repetition period as a control, followed immediately by a 60-second task period (i.e, animal words), a 60-second control period, another 60-second task period (i.e., transportation words), and ended with another 60-second control period. The total measurement period is 270 seconds. The total number of correct and unique responses will be computed to reflect their fluency ability.

NIRSIT Lite is a portable, non-invasive neuroimaging procedure used to measure hemodynamic changes, in terms of oxyhemoglobin (HbO), deoxyhemoglobin (HbR) and total hemoglobin (HbT), associated with neuronal activities of the cerebral cortex in response to attending a task within the given period of time. Optical signals will be recorded on a two-wavelength (780 and 850 nm), continuous-wave optical imaging system (NIRSIT Lite; OBELAB Co., Seoul, South Korea). The 15 channels with a 30-mm source-detector separation which cover the entire PFC area will be used in this study. In accordance with the international 10-20 EEG system, the center of the bottom probe row will be placed at the reference point Fpz. Consequently, channel 1 to channel 7 represent the right PFC, and channel 9 to channel 15 the left PFC. In addition, NIRSIT has an embedded gyroscope that enables online removal of motion artifacts.