To study the non-temporary effects of successive walks in forested areas ( shinrin - yoku ) on hypertension prevalence and blood pressure levels.

Data for the analysis were derived from the baseline survey of the Japan Multi-Institutional Collaborative Cohort (J-MICC) study in the Shizuoka area. Eligible participants were individuals aged 35–69 years who attended a health check-up center during 2006 and 2007. Of the 5,040 individuals who participated in the J-MICC study, Shizuoka, 4,666 were included in this analysis [3,174 men and 1,492 women; age (mean ± standard deviation) 52.1 ± 8.7 years]. The frequency of forest walking was estimated by a self-administrated questionnaire. Hypertension was defined as a systolic blood pressure ≥140 mmHg, a diastolic blood pressure ≥90 mmHg or, based on information provided in the questionnaire, the use of medication for hypertension.

After adjusting for age, body mass index (BMI), smoking status, alcohol consumption, and habitual exercise, the odds ratios of hypertension associated with forest walking once a week or more frequently, relative to less than once a month were 0.98 in men [95% confidence interval (CI) 0.68–1.42] and 1.48 (95% CI 0.80–2.71) in women. There was no significant trend between adjusted blood pressure levels and the frequency of forest walking.

The results of our cross-sectional study in a Japanese population show no association between either blood pressure levels or the prevalence of hypertension and the frequency of forest walking.