JMIR Publications

ABSTRACT

Background:

Cardiovascular disease (CVD) remains the leading cause of death worldwide; however, participation in cardiac rehabilitation (CR) remains suboptimal despite its proven benefits. Although wearable devices have emerged as scalable tools for remote CR delivery, the impact of wrist-worn devices on patients’ exercise capacity and physical activity remains unclear.

Objective:

To evaluate the effectiveness of wrist-worn wearable–guided CR in patients with CVD participating in Phase II or III CR.

Methods:

Electronic databases were systematically searched for randomized controlled trials published between January 2015 and November 2025. Eligible studies included adults (≥18 years) with CVD who underwent percutaneous coronary intervention or cardiac surgery (including coronary artery bypass grafting, valve surgery, or aortic surgery) and participated in Phase II–III CR using wrist-worn wearable devices in remote or hybrid programs. The primary outcomes were peak oxygen consumption (peak VO2), 6-minute walk distance (6MWD), and daily steps. Secondary outcomes included body mass index (BMI), waist circumference, anaerobic threshold (AT), grip strength, and quality of life (QoL). Random-effects meta-analyses were conducted using standardized mean differences (SMDs) and mean differences (MDs). The risk of bias was assessed at the outcome level by using the Cochrane Risk of Bias tool version 2. Subgroup and meta-regression analyses were performed to explore potential moderators, including age, sex, intervention duration, timing of CR initiation, exercise type, feedback modality, and device type.

Results:

Eighteen randomized controlled trials were included in the systematic review, of which 16 provided sufficient data for quantitative meta-analysis. In comparison with the control interventions, wearable-based home CR significantly increased peak VO2 (SMD = 0.48; 95% confidence interval [CI], 0.08–0.89; P = .026) and 6MWD (SMD = 0.49; 95% CI, 0.16–0.82; P = .009). Daily steps also increased significantly (SMD = 0.52; 95% CI, 0.24–0.81; P = .005). In addition, waist circumference was significantly reduced (SMD = −0.45; 95% CI, −0.84 to −0.06; P = .038). No statistically significant effects were observed on BMI, AT, grip strength, or QoL. Subgroup analyses demonstrated greater improvements in peak VO2 when CR was initiated during Phase II compared with Phase III, and when interventions primarily consisted of aerobic exercise. Meta-regression analysis revealed a significant association between the magnitude of peak VO2 improvement and the proportion of female participants.

Conclusions:

Wrist-worn wearable–guided CR significantly enhances exercise capacity, functional walking performance, and physical activity in patients undergoing Phase II–III CR, with additional benefits in central adiposity. Early initiation and aerobics-focused training may enhance outcomes, although the risks of bias, heterogeneity, and imprecision limit the certainty of the evidence. Clinical Trial: N/A