Does exposure to nature reduce blood pressure?
Moderate EvidenceIT DEPENDS
Emerging evidence suggests that nature exposure, including forest bathing and greenspace access, is associated with modest blood pressure reductions. However, most studies have methodological limitations and the mechanisms remain incompletely understood.
The Verdict
Emerging evidence suggests that nature exposure, including forest bathing and greenspace access, is associated with modest blood pressure reductions. However, most studies have methodological limitations and the mechanisms remain incompletely understood.
What the Evidence Shows
The concept that nature exposure lowers blood pressure has gained scientific attention particularly through Japanese 'shinrin-yoku' (forest bathing) research and urban greenspace epidemiology. Ideno et al. (2017) conducted a meta-analysis of 20 studies examining forest bathing and found statistically significant reductions in systolic blood pressure compared to urban control environments. Twohig-Bennett and Jones (2018) performed a broader systematic review of greenspace exposure and health, finding associations with reduced blood pressure, heart rate, and cortisol levels across multiple study designs. Bratman et al. (2019) provided a theoretical framework linking nature exposure to mental health through attention restoration, stress reduction, and increased physical activity. However, significant limitations constrain the evidence. Most forest bathing studies are short-term (hours to days), use small sample sizes, lack proper blinding, and employ crossover designs vulnerable to order effects. The blood pressure reductions, while statistically significant, are typically modest (2-5 mmHg systolic). It remains unclear whether the benefit comes specifically from natural environments or simply from stress-free leisure time in any pleasant setting. Confounding in observational greenspace studies is substantial: people living near parks tend to be wealthier, more active, and have healthier lifestyles overall.
Evidence Quality
3
Meta-Analyses
5
RCTs
15
Observational
Important Caveats
- ⚠️ Most studies are short-term and small, with limited blinding and high bias risk
- ⚠️ Blood pressure reductions are modest (2-5 mmHg) and may not persist
- ⚠️ Difficult to separate nature-specific effects from general relaxation/leisure
- ⚠️ Greenspace epidemiology is heavily confounded by socioeconomic factors
- ⚠️ Mechanisms may involve physical activity rather than nature exposure per se
Population Studied
Mostly healthy adults in Japan (forest bathing studies) and urban populations in Europe (greenspace epidemiology)
Dosage
Studies typically examine 15-minute to 3-hour nature walks or 2-3 day forest bathing programs
Duration
Acute effects last hours; sustained benefit from regular nature exposure requires ongoing access
Supporting Studies (3)
Effect of forest bathing trips on human immune function
Meta-AnalysisIdeno Y, Hayashi K, Abe Y, et al. · BMC Complementary and Alternative Medicine (2017)
Meta-analysis of 20 studies found forest bathing significantly reduced systolic blood pressure (mean reduction 3.15 mmHg) compared to urban control environments.
View paper (DOI) →Health and well-being benefits of spending time in nature: a systematic review and meta-analysis
Meta-AnalysisTwohig-Bennett C, Jones A. · Environmental Research (2018)
Systematic review of 143 studies found greenspace exposure significantly associated with reduced diastolic blood pressure, heart rate, and salivary cortisol, suggesting broad physiological stress reduction.
View paper (DOI) →Nature and mental health: an ecosystem service perspective
ObservationalBratman GN, Anderson CB, Berman MG, et al. · Science Advances (2019)
Comprehensive review established theoretical and empirical framework linking nature exposure to reduced stress, improved mood, and lower physiological arousal including cardiovascular markers.
View paper (DOI) →Contradicting Studies (1)
Outdoor blue spaces, human health and well-being: a systematic review of quantitative studies
Meta-AnalysisGascon M, Triguero-Mas M, Martinez D, et al. · Environmental Research (2015)
Systematic review of greenspace and cardiovascular health found inconsistent evidence, with many studies showing null results and significant methodological heterogeneity preventing firm conclusions.
Why this disagrees:
Highlights that the evidence base has substantial inconsistency, with many studies finding no significant cardiovascular effect from greenspace exposure, suggesting publication bias may inflate positive findings.