Association of Perioperative Steps and Heart Rate Variability from Wearable Devices with Surgical Outcomes

Surgical recovery is dependent on physiologic reserve, functional capacity, and wellness status. We sought to delineate the association between perioperative changes in daily steps, heart rate variability (HRV), and self-reported wellness and length of stay (LOS), complications and readmissions.

Adults undergoing inpatient surgery with greater than or equal to 30 preoperative and greater than or equal to 30 postoperative days of data were identified from the All of Us database. Exposures included postoperative changes in daily steps and HRV relative to their preoperative baseline. Wellness was assessed in a sensitivity analysis using the sleep disturbance, pain, anxiety, depression and low energy/fatigue composite score. Multivariable regression analyses, adjusted for relevant factors, were used to assess outcomes, including LOS, 30-/90-day complications, and readmissions.

Among 66,345 patients who underwent a surgical procedure, 1,965 patients (mean age 50.4 years, 69.5% women) were included in the final analytic cohort. Each postoperative +1,000 steps per day relative to preoperative baseline was associated with reduced LOS (incidence rate ratio 0.94, 95% CI 0.90 to 0.99) and lower odds of 30-day (adjusted odds ratio [aOR] 0.83, 95% CI 0.69 to 1.00) and 90-day (aOR 0.82, 95% CI 0.70 to 0.96) complications. Incremental increases in steps were also associated with lower odds of 30-day (aOR 0.85, 95% CI 0.76 to 0.96) and 90-day (aOR 0.84, 95% CI 0.75 to 0.94) readmission. Postoperative HRV changes and self-reported wellness were not associated with any postoperative outcome (p > 0.05).

Postoperative step count was the most actionable correlate of recovery across endpoints, whereas postoperative HRV change and self-reported wellness conferred limited independent prognostic value. These findings support integrating wearables into Enhanced Recovery After Surgery as preoperative HRV-informed triage and postoperative step-guided recovery, while emphasizing less reliance on subjective patient-reported measures to inform discharge or clinical decisions.