Effects of Autogenic Training on Heart Rate Variability and Heart Rate Recovery in Japanese Obese/Overweight Male Workers

Objective: Obesity-induced autonomic nervous system (ANS) dysfunction is related to cardiac disease. The purpose of this study is to examine the effect of autogenic training (AT), a therapeutic relaxation technique, on cardiac ANS functions as evaluated by heart rate variability (HRV) and heart rate recovery (HRR) in Japanese obese/overweight subjects. Methods: Subjects were 40 obese/overweight male workers (42.7 ± 8.8 years old, BMI 28.8 ± 3.3 kg/m2). The subjects were randomly assigned to an AT intervention group and a control group. Subjects of the intervention group were required to perform the AT training procedures (first-third steps) for three months, while the control group participants were waiting. Before and after intervention, HRV was calculated using a 24 hr Holter ECG, and HRR was assessed by a treadmill test. In addition, Profile of Mood States (POMS), job stress and sleep conditions were assessed. Effects of AT intervention were statistically examined using analysis of covariance (ANCOVA). Results: For the HRV, the ratio of the Low Frequency to the High Frequency (LF/HF) during sleep was significantly reduced in the AT group (-39.2% and -0.6%, respectively, p=0.009). HRR was lengthened in the AT group (5.2% and 0.6%, respectively, p=0.042). In addition, the Confusion-Bewilderment score in POMS was improved in the AT group. However, mediation analysis indicated that the Confusion-Bewilderment score was not considered as a mediator between AT and ANS. Conclusions: A three month AT intervention improved cardiac ANS activities in Japanese obese/overweight men. These results suggest the beneficial effects of AT on obesity-related cardiovascular conditions.