Analysis of Individual Variations in Autonomic Responses to Urban and Forest Environments

Hiromitsu Kobayashi,Yoshifumi Miyazaki,Chorong Song,Harumi Ikei,Takahide Kagawa

doi:10.1155/2015/671094

Abstract

Autonomic responses to urban and forest environments were studied in 625 young male subjects. The experimental sites were 57 forests and 57 urban areas across Japan. The subjects viewed the landscape (forest or urban environment) for a period of 15 min while sitting on a chair. During this period, heart rate variability (HRV) was monitored continuously. The results were presented as histograms and analyzed with special reference to individual variations. Approximately 80% of the subjects showed an increase in the parasympathetic indicator of HRV (lnHF), whereas the remaining subjects showed a decrease in the parasympathetic activity. Similarly, 64.0% of the subjects exhibited decreases in the sympathetic indicator of HRV (ln[LF/HF]), whereas the remaining subjects showed opposite responses. Analysis of the distribution of HRV indices (lnHF and ln[LF/HF]) demonstrated the effect of forest environments on autonomic activity more specifically than the conventional analysis based on the difference in mean values.

Highlights

There has been growing interest in the effects of the natural environment on human health
The current study investigated the effects of forest environments on autonomic nervous activity using heart rate variability (HRV) as an indicator
The current study investigated the frequency components of HRV in 625 young Japanese males in urban and forest environments

Summary

Introduction

There has been growing interest in the effects of the natural environment on human health. Studies have demonstrated that exposure to a forest environment results in reduced physiological indicators for stress. The current study investigated the effects of forest environments on autonomic nervous activity using heart rate variability (HRV) as an indicator. Use of a portable heart rate monitor can provide ambulatory recording of HRV. These advantages might be maximized in field studies rather than experimental studies. Most previous studies on physiological responses to environments have focused on the differences in the mean value; individual variations were considered an error or impurities. The current study utilized a large sample size and can provide a new perspective on the physiological responses to natural environments

Materials and Methods

Results and Discussion

Conclusion