Effects of an individualized and time based training program on physical fitness and mood states in recreational endurance runners

Previous studies have shown that training guided individually by heart rate variability (HRV) elicits benefits on endurance performance. Meanwhile complex programs, which use HRV assessments to tailor exercise prescriptions to individual needs, are included in portable training computers. However, knowledge on health and fitness benefits of such training programs is still limited. Therefore, the aim of the present study was to investigate effects of HRV-based training included in a portable training computer vs general time-based training on aerobic fitness, half-marathon time as well as mood and mental states. Male (n=10) and female endurance runners (n=10) were recruited and randomly assigned to HRV-based (STAR) and predefined time-based training (TBT). At baseline and after 16 weeks of training an incremental exercise test with spirometry was performed to assess aerobic power. Additionally, mood and mental states were asked. After the training period all subjects took part in a half-marathon. Matched-pairs were selected to compare groups based on similar relative weekly energy expenditure during training. With no differences between groups, STAR and TBT reduced weight (p=0.029), body fat (p=0.002) as well as systolic and diastolic blood pressure (p≤0.001). Maximal oxygen uptake significantly increased from 43.0 ± 8.3 to 46.1 ± 9.0 mlminkg (p≤0.001) and 43.2 ± 4.8 to 46.7 ± 4.7 mlminkg (p≤0.001) in STAR and TBT, respectively. Moreover, both groups improved maximal velocity (TBT: 0.81 + 0.40 kmh vs STAR: 0.74 + 0.39 kmh; p≤0.001) and completed the half-marathon with similar finish times (01:54:35 ± 00:14:02 [hh:mm:ss] vs. 01:52:42 ± 00:13:45 [hh:mm:ss]; p=0.789). Regarding mood and mental states, no major changes were observed over the training period. In conclusion, both HRVand time-based training elicited similar improvements in aerobic power and body composition. Consequently, HRV-dependent exercise prescriptions serve as a practical tool for day-to-day periodization of aerobic exercise.