Effects of forest bathing on pre-hypertensive and hypertensive adults: a review of the literature
Katherine Ka-Yin Yau & Alice Yuen Loke
Environmental Health and Preventive Medicine volume 25, Article number: 23 (2020)
Abstract
The aim in this literature review was (1) to explore the physiologically and psychologically therapeutic benefits of forest bathing on adults suffering from pre-hypertension or hypertension, and (2) to identify the type, duration, and frequency of an effective forest bathing intervention in the management of pre-hypertension and hypertension, so as to provide directions for future interventions or research. The electronic databases PubMed, Cochrane Library, CINAHL, PsyINFO, and the China Academic Journals (CAJ) offered through the Full-text Database (CNKI) were searched for relevant studies published from the inception of the databases to April 2019. Of the 364 articles that were identified, 14 met the criteria for inclusion in this review. The synthesis of the findings in the included studies revealed that forest bathing interventions were effective at reducing blood pressure, lowering pulse rate, increasing the power of heart rate variability (HRV), improving cardiac-pulmonary parameters, and metabolic function, inducing a positive mood, reducing anxiety levels, and improving the quality of life of pre-hypertensive or hypertensive participants. Forest walking and forest therapy programs were the two most effective forest bathing interventions. Studies reported that practicing a single forest walking or forest therapy program can produce short-term physiological and psychological benefits. It is concluded that forest bathing, particularly forest walking and therapy, has physiologically and psychologically relaxing effects on middle-aged and elderly people with pre-hypertension and hypertension.1
Comment
Hypertension is a risk factor for cardiovascular events and stroke and is results from a range of diet and lifestyle conditions including highly processed foods, excess calorie intake, stress, lack of sleep, and microbiota disturbances.
Hypertension is typically defined as > 140/90 mmHg. While the main interventions used are medication and limiting sodium intake, reductions in dietary salt (sodium) while consistently resulting in reduced blood pressure (i.e. a ‘significant’ finding) they do not result in meaningful reductions in blood pressure, except with extreme restriction likely to cause other adverse health effects. Exercise and other interventions are also useful for reducing blood pressure.
Everyday life stress has been demonstrated to cause meaningful and consistent elevations in blood pressure and ‘forest bathing’ (Shinrin-yoku), or the spending of time in nature, especially in wooded areas, and being exposed to natural stimuli like tress, woods, flowers, fungi, and flowing water. This has demonstrated a range of positive effects on health in previous research including for improvements in immune function, heart rate, blood pressure, inflammation, depression, and might even help to protect against cardiovascular disease and cancer.
In this review, the following outcomes were highlighted:
- Forest bathing is effective for reducing blood pressure (by around 5-15%)
- Reduced heart rates of 3-6%
- Possible reductions in cortisol
- Reduced inflammation
- Reduced depression and improved anxiety
- Improved mood and quality of life overall
During forest bathing, it is important to slow down and be mindful of your surroundings and how you are within those surroundings.
Going for a daily walk in your local park or a natural area near your work or home is likely to provide appreciable health and quality-of-life benefits
It is clear, based on the evidence that being surrounded by nature has a significant benefit to health when compared to urban environments (many of the studies reviewed compared urban to natural environment comparisons). Going for a daily walk in your local park or a natural area near your work or home is likely to provide appreciable health and quality-of-life benefits.
References
1. Yau KK-Y, Loke AY. Effects of forest bathing on pre-hypertensive and hypertensive adults: a review of the literature. Environmental Health and Preventive Medicine. 2020;25(1):23.
