In this study, we enrolled community-dwelling middle-aged and older adults who were capable of participating in physical exercise. Participants were recruited from local community centers and health clinics. Of 155 individuals screened, 120 were enrolled (mean age 63.0, SD 4.5 years; 97/120, 80.8% female). Eligibility criteria included age 50-70 years, absence of clinically diagnosed cardiovascular, musculoskeletal, metabolic, or cognitive disorders, and no regular participation in structured exercise within the preceding 6 months (defined as <1 session/week). Exclusion criteria comprised current use of medications affecting blood pressure, lipid metabolism, or glucose regulation (eg, antihypertensive agents, statins, or antidiabetic drugs), as well as current smoking or smoking cessation within the past 6 months.

This study was a single-blind randomized controlled trial conducted among community-dwelling middle-aged and older adults. Following baseline assessments, participants were randomly assigned in a 1:1:1:1:1 ratio to one of the 5 groups—CTC12, TC24, square dance, walking, or a control group. Randomization was performed using a computer-generated sequence prepared by an independent researcher, with allocation concealed in sequentially numbered, opaque, sealed envelopes, which were opened after baseline assessments. Outcome assessors and laboratory personnel were blinded to group allocation, and participants were informed only of their assigned intervention. Each participant received a unique identification code, and all assessments were conducted according to standardized procedures by trained evaluators. No sex-based restrictions were applied, and all interventions and assessments were implemented uniformly across sexes. Before the intervention, participants completed a 1-week familiarization period to facilitate adaptation, enhance adherence, and ensure correct execution of the assigned exercises.

The study protocol was approved by the Ethics Committee of Beijing Fengtai Hospital (approval P2024022) and complied with the Declaration of Helsinki. All participants provided written informed consent after receiving detailed information regarding study objectives, procedures, potential risks, and participant rights. Assessments were conducted by licensed medical professionals from Beijing Fengtai Hospital and Nankang District Hospital of Traditional Chinese Medicine (Ganzhou, Jiangxi Province). Adverse events were evaluated and managed on-site. Personal data were anonymized and coded to ensure confidentiality and were used exclusively for research purposes.

After completing the study, participants were provided with full electronic instructional videos for CTC12, TC24, and square dancing.

Participants in each intervention group attended supervised sessions twice weekly for 90 minutes over a 12-week period, conducted from 8 to 9:30 AM. The interventions were defined as follows: (1) CTC12, which emphasized explosive techniques (fa jin), jumps, and complex transitions to enhance neuromuscular coordination and cardiopulmonary function; (2) TC24, a standardized and simplified form of Yang-style Tai Chi, focusing on breathing rhythm, flexibility, and balance [37]; (3) square dance, a moderate-to-high intensity aerobic dance performed at 60%-75% of maximum heart rate (HR) [50]; (4) walking, performed as brisk walking at 3.5-4.0 km/h on flat terrain, targeting 50%-60% of maximum HR, and monitored using HR devices [50,51]; and (5) control, continued daily activities with no additional structured exercise.

All sessions were conducted outdoors under temperatures ranging from 24 °C to 28 °C. Although humidity and air circulation were not controlled, participant safety and comfort were ensured throughout. Each session began with a standardized 10-minute warm-up consisting of light aerobic activity and joint mobility exercises. Tai Chi interventions (CTC12 and TC24) were led by Shaoqing Zeng, with more than 10 years of teaching experience and recognized competitive achievements at the city level. Square dance and walking interventions were designed and supervised by WS, with a doctoral degree in Sports Science and extensive experience in physical education and exercise interventions, who had participated in the design and implementation of several community-based exercise programs (Multimedia Appendix 1).

All statistical analyses were performed using R (version 4.2.1; R Core Team). Continuous variables are presented as mean (SD). Within-group comparisons were assessed using paired t tests, and between-group comparisons were conducted using 1-way ANOVA with Tukey post hoc tests. Normality and homogeneity of variance were evaluated using the Shapiro-Wilk and Levene tests, respectively. To address potential inflation of type I error due to multiple comparisons across outcomes (eg, blood pressure, fasting glucose, lipids, IL-6, SPPB, and WHOQOL subdomains), the false discovery rate correction was applied. All tests were 2-tailed, with statistical significance defined as P<.05. Adjusted P values, effect sizes, and 95% CIs were reported to complement dichotomous significance testing.

As illustrated in the CONSORT (Consolidated Standards of Reporting Trials) diagram, 155 individuals were screened, of whom 120 (77.4%) eligible community-dwelling middle-aged and older adults were enrolled. During the 12-week intervention, 7 participants withdrew due to personal reasons or insufficient attendance (<90%) and were subsequently classified as dropouts. Ultimately, 113 participants completed the intervention and all assessments. The final group sizes were as follows: (1) CTC12: n=22, (2) TC24: n=23, (3) square dance: n=22, (4) walking: n=23, and (5) control: n=23 (Figure 1, Table 1).

Postintervention comparisons showed varying patterns across subdomains. Q1 scores were highest in the square dance group and lowest in the control group, with a marginal group effect (P=.06). Q2 scores were significantly higher in the CTC12 and square dance groups than in the control group (P=.005), indicating improved psychological health. No significant differences were observed for Q3 (P=.13), although the square dance group had the highest mean score. Similarly, no significant between-group differences were observed for Q4 (P=.78). For Q5, a near-significant group effect was observed (P=.09), with higher scores in the CTC12 and square dance groups than in the control group. Q6 did not differ significantly among groups (P=.13), although the CTC12 group showed the highest mean overall quality of life score (Table S2 and Figure S2 in Multimedia Appendix 3).

This 12-week exercise intervention demonstrated significant benefits in the CTC12 and square dance groups. Both interventions improved lipid profiles, with TC reduced in the square dance group and triglyceride and LDL-C reduced in both the CTC12 and square dance groups, while no significant changes were observed in FPG or IL-6. Functional outcomes also improved, as reflected by increased SPPB scores in both groups and improved ADL scores in the square dance group. WHOQOL scores significantly improved in the CTC12, square dance, and walking groups, indicating enhanced quality of life. Collectively, these findings support the effectiveness of CTC12 and square dance in improving lipid metabolism, physical function, and quality of life in middle-aged and older adults.

Regarding blood pressure, although no significant changes were observed in DBP, SBP, or PP across the groups, small trends in blood pressure changes were noted. From a clinical perspective, such small blood pressure changes are unlikely to represent meaningful short-term cardiovascular risk reduction, although minor population-level shifts have been associated with long-term risk trends in epidemiological studies [65]. Mechanistically, CTC12 may influence SBP through coordinated breathing and postural control, potentially modulating autonomic balance and arterial compliance [48]. The square dance intervention, characterized by rhythmic and moderate-to-high intensity movements, may contribute to improvements in large-artery elasticity, which could partly explain the observed PP reduction [66]. Walking, as a low-intensity aerobic activity, may enhance endothelial function and peripheral vasodilation, contributing to modest DBP changes [67]. These mechanisms provide plausible explanations for the observed directional trends but do not imply clinically significant blood pressure reductions within the intervention period of this study.

The CTC12 and square dance groups demonstrated significant reductions in TC, triglyceride, and LDL-C, while HDL-C was significantly increased in the CTC12 group, indicating beneficial effects on lipid metabolism. The CTC12 regimen, which incorporates strength, coordination, and breathing control, may enhance lipid homeostasis and contribute to increases in HDL-C [68]. In contrast, square dance may improve lipid profiles through enhanced lipoprotein lipase activity, facilitating very-low-density lipoprotein clearance and cholesterol transport [68]. Although the CTC12 group exhibited greater increases in HDL-C, and the square dance group showed more pronounced reductions in TC, both groups demonstrated complementary effects on lipid regulation, which may have beneficial implications for cardiovascular prevention [69]. The square dance group exhibited a more pronounced reduction in TC, whereas the CTC12 group was more effective in elevating HDL-C, indicating distinct yet complementary lipid-regulatory mechanisms. Both groups achieved clinically relevant lipid thresholds (eg, triglyceride<1.7 mmol/L and LDL-C<3.4 mmol/L), underscoring their potential role in primary cardiovascular prevention. This suggests that the observed lipid improvements were not only statistically significant but also potentially relevant for practical cardiovascular risk management in community-dwelling older adults [70].

Although not statistically significant, the control group exhibited a worsening trend in TC, triglyceride, and other cardiometabolic markers, which may reflect the absence of structured physical activity [71].

No significant changes in IL-6 levels were observed across intervention groups. This may reflect the relatively healthy baseline status of the participants and the limited duration of the intervention. In such populations, longer intervention periods may be required to detect measurable changes in inflammatory markers. Although mind–body interventions, such as CTC12 and Square Dance, may influence parasympathetic activity and low-grade inflammation, these effects did not translate into detectable changes in IL-6 within the short intervention period. Future studies with extended follow-up are needed to clarify these effects [72].

The CTC12 group demonstrated the greatest improvements in SPPB scores, followed by the square dance group, whereas no significant changes were observed in the walking group. The coordinated activation of core and lower-limb musculature in CTC12 likely contributes to improvements in balance, coordination, and postural control, thereby reducing the risk of falls and improving gait performance. These improvements may be clinically meaningful, as better SPPB performance is closely associated with mobility, reduced fall risk, and preserved functional independence in older adults [73].

Square dance, characterized by rhythmic movement and group participation, was associated with increases in BMR, suggesting enhanced metabolic activity and energy efficiency, which may help delay age-related metabolic decline [74].

WHOQOL scores improved in the CTC12, square dance, and TC24 groups, with the most pronounced improvements in psychological health gains (Q2) observed in the CTC12 and square dance groups. The underlying mechanisms appear distinct. CTC12 may enhance emotional regulation and self-efficacy through long-term cognitive engagement and controlled breathing, facilitating parasympathetic activation [75]. Conversely, the square dance may improve mood, social cohesion, and subjective well-being through social interaction, rhythmic movement, and music [76]. These findings suggest that CTC12 emphasizes internal self-regulation, whereas square dance operates through external social reinforcement, highlighting the importance of tailoring interventions to individual psychological and social profiles [63]. A slight worsening trend in psychological scores was observed in the control group, which may reflect the effects of prolonged inactivity [77].

Mean exercise HR across all intervention groups remained within 50%-70% of HR_max, consistent with American College of Sports Medicine guidelines for middle-aged and older adults [78]. No falls or cardiovascular events were observed in the CTC12 group, despite the inclusion of explosive movements, likely due to structured warm-up protocols, progressive difficulty, and professional supervision. Similarly, no injuries were reported in the square dance group, despite engaging in moderate-to-high intensity activities. Attendance exceeded 90% across all groups, indicating high adherence and feasibility. These findings support the safety and applicability of these interventions in community-based settings.

A descriptive dose-related interpretation was used to examine how differences in exercise intensity and physiological load relate to the breadth of observed health benefits. CTC12 and square dance improved a greater number of outcomes and were therefore compared in terms of exercise dose characteristics and physiological demand. Square dance demonstrated higher energy expenditure (386.7 kcal) and ΔHR (46.7 bpm; approximately 72%-75% HR_max), reflecting moderate-to-high intensity activity. This higher intensity may explain the more rapid improvements in physical function but may also exceed optimal safety thresholds for some older adults, particularly those with cardiovascular risk factors, potentially limiting long-term sustainability. Nevertheless, square dance led to more immediate improvements in physical function, particularly in balance and muscular endurance, possibly due to its higher energy expenditure [79]. CTC12 achieved relatively high energy expenditure (363.8 kcal) and metabolic activation while maintaining a lower cardiovascular load (ΔHR=29.5 bpm; approximately 60%-65% HR_max), consistent with recommended safety ranges for older adults [80]. Although improvements appeared more gradual, CTC12 was associated with long-term benefits across physical, psychological, and quality-of-life domains with a lower risk of excessive fatigue or cardiovascular strain. These findings suggest distinct practical roles for each intervention. Square dance may be more suitable for individuals seeking higher-intensity activity and faster functional gains, whereas CTC12 may provide a more sustainable, lower-risk option for long-term health maintenance [81-83]. From an implementation perspective, both interventions are feasible in community settings; however, CTC12 may be more appropriate for broader populations due to its moderate intensity and lower cardiovascular demand, whereas square dance may require closer monitoring in higher-risk individuals [84,85].

This study has some limitations. The relatively small sample size (n=22 per group) may have limited statistical power, and the 12-week intervention period may not have been adequate to capture long-term effects. Although outcome assessors were blinded to group allocation, participants were necessarily aware of their assigned intervention due to the distinct characteristics of each exercise modality. This awareness may have introduced expectancy-related influences, particularly for self-reported outcomes such as quality of life (eg, WHOQOL). However, such effects are less likely to have substantially influenced objective measures, including blood pressure, biochemical indicators, and physical function. Laboratory personnel responsible for biochemical analyses were blinded to group assignment, which helped mitigate detection bias.

Although the final sample size was adequate for the primary group×time analysis, the study may have been underpowered to detect differences in some secondary outcomes. Accordingly, these findings should be interpreted with caution. In addition, advanced cardiovascular assessments were not included, which limits the ability to characterize underlying physiological changes in greater detail. Future studies should include larger and more diverse samples, extend intervention duration, and incorporate participants at elevated clinical risk. The application of advanced analytical approaches, such as structural equation modeling, may facilitate a more comprehensive understanding of the interrelated metabolic, neural, emotional, and social pathways influenced by exercise. Building on the findings of this study in relatively healthy middle-aged and older adults, further research in populations with cardiovascular disease, metabolic disorders, and other chronic conditions is warranted to clarify clinical benefits and underlying mechanisms across different disease contexts.

In summary, we demonstrated that both CTC12 and square dance were associated with improvements in blood lipid profiles, physical function, and quality of life in middle-aged and older adults. CTC12 was associated with improvements across multiple health indicators, whereas square dance showed more pronounced effects on physical function, metabolic activity, and emotional well-being. In contrast, the effects observed for TC24 and walking were more limited and were confined to selected outcomes. These findings support the role of structured, moderate-to-high-intensity exercise in promoting healthy aging and provide preliminary evidence to inform the development of targeted exercise interventions for age-related health conditions.