Beta-1 Band Functional Connectivity Mediates the Effects of Acute Exercise on Cognitive Flexibility in Older Adults With Cognitive Impairment: A Randomized Controlled Trial

• Baduanjin (Other): This study adopted the Baduanjin Health Qigong standard issued by the General Administration of Sport of China in 2003. . The exercise intervention lasted 30 min in total, including a 2-min preparation phase, a 26-min main phase and a 2-min cool-down phase. Two weeks before the formal intervention, participants received training from a martial arts professional coach, and only those who had achieved fluent and proficient performance of the movements were allowed to take part in the formal intervention. Participants were required not to engage in any exercise during the 3 days before the intervention. The Baduanjin group received movement instruction from a professional martial arts coach and performed the exercise in an indoor dance room.
• Brisk walking (Other): This study adopted the Brisk Walking standard issued by the General Administration of Sport of China in 2017. A treadmill manufactured by Topkang Technology Co., Ltd. (model: SJAI) was used. The exercise intervention lasted 30 min in total, including a 2-min preparation phase, a 26-min main phase and a 2-min cool-down phase. Before the intervention, participants received instruction and training from a professional track-and-field coach, and only those who had achieved fluent and proficient performance of the movements were allowed to participate in the formal intervention. Participants were required not to engage in any exercise during the 3 days before the intervention. The brisk walking group received movement instruction from a professional track-and-field coach and performed the exercise on an indoor treadmill.
• Resistance band (Other): The resistance exercise programme in this study was based on the framework of the American College of Sports Medicine (ACSM) guidelines. A portable and safe resistance band (TheraBand progressive resistance band, USA) was used as the intervention tool. The resistance-band resistance training consisted of 10 exercises in total, including 4 upper-limb movements (seated chest press, seated reverse fly, seated biceps curl and seated shoulder press) and 6 lower-limb movements (seated knee lift, seated knee extension, seated knee flexion, seated leg press, seated hip abduction and standing calf raise). Each movement was performed for 2 sets of 12 repetitions. Rest intervals were 30-60 s within sets and 30-60 s between sets, and the movement tempo was controlled at 2 s for the eccentric phase and 2 s for the concentric phase. The resistance-band group received movement instruction from a professional fitness coach and performed the exercise in an indoor activity room.
• health education materials (Other): After arrival, participants in the control group watched health education materials and received health education at the community activity center. Detailed descriptions of the exercise interventions for the four groups are provided in the Supplementary Materials.

Primary outcomes

• Cognitive flexibility [A total of 2 weeks from the beginning to the end]: Cognitive flexibility was assessed using the More-odd-shifting task paradigm, which was designed with E-prime software. The testing environment was quiet, well ventilated and moderately lit. The stimuli used in the More-odd-shifting task were red or green Arabic numerals from 1 to 9, excluding 5. Participants were required to make key-press responses according to the task instructions when the stimuli appeared. The More-odd-shifting task consisted of three conditions: Condition 1, judgment of numerical magnitude; Condition 2, judgment of parity; and Condition 3, mixed judgment of numerical magnitude and parity.

Secondary outcomes

• Brain functional connectivity [A total of 2 weeks from the beginning to the end]: Brain functional connectivity analysis was performed using MATLAB scripts, and graph-theoretical analysis was carried out using the BrainNet Viewer toolbox. Phase locking value (PLV) was used, and brain functional connectivity was evaluated from two dimensions: connectivity strength and density. In this study, PLV was calculated for the δ, θ, α1, α2, β1 and β2 bands of resting-state EEG using MATLAB, and the formula is shown in Equation (1). Here, i is the imaginary unit, Δt is the time interval between two consecutive samples, and N is the total number of samples. PLV is an index used to quantify phase synchrony in EEG signals and assesses whether two signals maintain a relatively stable phase relationship over time. Its value ranges from 0 to 1, where 1 indicates complete synchrony and 0 indicates no synchrony. PLV is commonly used to investigate phase synchrony between different brain regions, particularly functional connectivity related to neural oscillations.

Sex: All, ages: 60 Years to any

Inclusion Criteria:

* Age ≥ 60 years old, gender not restricted;
* Patients or their guardians report subjective cognitive decline;
* Montreal Cognitive Function Assessment Scale < 26 points;
* Duration of cognitive dysfunction ≥ 6 months;
* Willing to sign the informed consent form;
* Good physical condition and able to complete the test;

Exclusion Criteria:

* History of severe mental disorders (severe depression, schizophrenia, etc.);
* Using drugs that affect cognition (such as sedatives, antidepressants, etc.);
* Limited language ability;
* Consumed caffeine or alcohol the day before the test;
* Suffering from serious diseases or injuries that make participation in the test inappropriate.