Objective: The purpose of this study was to report the sustained changes in heart rate variability (HRV) observed in 6 patients undergoing continuous chiropractic care for the correction of vertebral subluxations. Clinical Features: Six patients between 25 to 55 years of age all presented with primarily musculoskeletal complaints for chiropractic care in a private practice setting. All patients were nonsmokers with no reported cardiac pathology. All patients were initially assessed for indicators of vertebral subluxation before being accepted for chiropractic care, and were monitored for changes in HRV scores over time. Intervention and Outcomes: Chiropractic care, using Diversified and Thompson techniques to correct vertebral subluxations, was provided for an initial period of 10 to 52 weeks at a frequency of 2 to 3 visits per week. HRV, measured by SSDN, increased over the early part of their course of chiropractic care, and these increases were sustained whilst the patient remained under long term continuous care in all 6 patients. Improvements in SDNN ranged from 50% to greater than 300% as compared to pre-care values. Conclusion: Patients receiving continuous chiropractic care to correct vertebral subluxation demonstrated a sustained improvement in HRV. This novel finding objectively demonstrates long-term change consistent with improved neurophysiological regulation, adaptability and resilience in patients undergoing chiropractic care, and suggests the utility of chiropractic care for outcomes greater than only musculoskeletal improvements.