Easker, Aaron2025-01-072025-01-072024-06https://hdl.handle.net/11299/269158University of Minnesota M.S. thesis. 2024. Major: Kinesiology. Advisor: Christopher Lundstrom. 1 computer file (PDF); 86 pages.Introduction: Increased heart rate variability (HRV) and faster heart rate recovery (HRR) after exercise have been observed with increased cardiovascular fitness. The purpose of this study was to assess the relationship between changes in HRV and HRR on running performance over the course of a marathon training distance running program. Methods: To investigate this relationship, HRV and HRR were measured in recreational runners during recovery from maximal intensity cardiovascular testing at the beginning and end of a marathon training program in college-aged students. Running performance was measured at these same time periods, on separate days, with the use of a 2-mile (3,218m) time trial. Paired t-tests, correlational analysis, and a multiple linear regression were used to assess the relationships between these. Results: Participants improved in VO2 max and 2-mile time trial performance over the course of the training program. Heart rate recovery improved during the first and second minute, post-maximal exercise. Select HRV variables improved during this post-maximal exercise recovery period, indicating improvements in parasympathetic function. Changes in HRV and HRR variables did not strongly predict changes in running performance. Conclusion: These findings confirm that endurance training leads to changes consistent with improved parasympathetic function. Tracking changes in HRV and HRR over time and their relationship with improvements in performance should be further explored in different populations.enThesis or Dissertation