Effects of Forest Bathing on Blood Pressure and Heart Rate in Older Adults in Mexico

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This article reads well and explains in introduction why the study and findings are significant and original. It refers to existing studies through introduction and discussion. It could include further literature support for particular points made and earlier definition for significant indicators for the study. See specific comments:

Line 90-91: Provide definition of systolic and diastolic blood pressure. In line 217 and 218 it is explained but could be more obviously explains in the introduction. As findings are significant and insignificant for these categories/indicators.

Line 100-101: Line 100-101. Provide literature support and maybe examples of significant reduction and causal associations.

Line 121-123: Limitations can be presented here with specifics of study population size. Or in a different section, after methods and before discussion. Or in discussion.

The limitation of the study population size could include the size of the study population and then information about records for each participant.

The greater perceived benefit for older adults could be presented as a limitation but also seems to be a specific of the study and therefore findings. As the study population is in heading, abstract and introduction about older adults, it is quite clear that it is the study population that findings are relevant to. It is however excellent to define the findings as specific to the demographic of the study population, therefore avoiding an assumption of defined benefits for other age groups. 

Example: Findings are specific to older adults and should not be assumed as specific benefits for other ages groups, nor benefits as only for this age group. 

Recommendations are clearly included in the article. They could address these limitations as defined by the authors. Examples: include further studies for the same age group, and for different age groups of similar health conditions. And/or for different or same age groups with health conditions as the variable.

Line 161-166: Could be better written to associate air quality with the factors listed and then with noise. The point about noise as associated with air quality indicates that these other factors related to air quality influence noise exposure. Are they, or are other noises and distance from urban noise the reason for reduced noise?

Line 242-243: 18 participants or 18 records for the 11 participants, or 18 records for # of participants.

Table 2 is very good with statistical significance written as yes and no.

Discussion

Line 270 - 298:

The discussion explains how findings support existing studies, according to heart rate per minute (not significant) and systolic and diastolic blood pressure (significant). It also and therefore highlights systolic and diastolic blood pressure as significant indicators for cardiovascular effect.

In discussion before or after stating a positive influence, provide written example of why the difference in heart beat per minute and blood pressure is or is not statistically significant with literature support.

Conclusion

The conclusion could include specifics of the program, location and designed guided walking and sensory plans for the guided walking. That it is important that forest bathing, and forest interactions for health benefit are designed, planned and guided.

Further comment.

With a small study population (11) but with 45 records. The article could, in methods, or in limitations explain how records for participants can be considered alongside study population size.

The limitations of the study are included but could be presented in a separate subheading with recommendations for future studies to improve and increase studies and study findings for the region.

 

 

 

Author Response

Line 90-91: Provide definition of systolic and diastolic blood pressure. In line 217 and 218 it is explained but could be more obviously explains in the introduction. As findings are significant and insignificant for these categories/indicators.

1. The definitions of systolic and diastolic blood pressure included in “Research Design” were incorporated in the introduction.
2. Systolic and diastolic blood pressure were considered separate study variables. This text was maintained in “Research Design”.

Line 100-101: Line 100-101. Provide literature support and maybe examples of significant reduction and causal associations.

1. Bibliographic reference was provided for “The practice of FB has previously been documented to produce a significant reduction in blood pressure.”.
2. “Twenty trials involving 732 participants were reviewed. Systolic blood pressure of the forest environment was significantly lower than that of the non-forest environment. Additionally, diastolic blood pressure of the forest environment was significantly lower than that of the non-forest environment”
3. The new reference is:  Ideno, Y., Hayashi, K., Abe, Y., Ueda, K., Iso, H., Noda, M., Lee, J.S., Suzuki, S., Blood pressure-lowering effect of Shinrin-yoku (Forest bathing): a systematic review and meta-analysis. BMC Complementary and Alternative Medicine 2017, 17, 409, 1-12. https://doi.org/10.1186/s12906-017-1912-z

Line 121-123: Limitations can be presented here with specifics of study population size. Or in a different section, after methods and before discussion. Or in discussion.

1. Limitations of the work were moved from Introduction to Discussion, adding the preponderance of women as another limitation.

The limitation of the study population size could include the size of the study population and then information about records for each participant.

1. The following table was added:

2. TITLE STUDY POPULATION AND NUMBER OF RECORDS/ participant (MAXIMUM 5)

   Participants			Num. of sessions in which he/she participated	Disease that increases the risk of vascular complications	Highest systolic pressure	Highest diastolic pressure
   Number	Sex	Age in years			Mm Hg	Mm Hg
   1	Female	61	4		128	87
   2	Female	64	3		125	87
   3	Female	66	5	Diabetes type 2	149	92
   4	Female	67	4		169	97
   5	Female	67	2	Diabetes type 2	140	86
   6	Male	68	5		129	90
   7	Male	68	5	Diabetes type 2	132	87
   8	Female	69	5		123	82
   9	Female	71	3	Diabetes type 2	118	82
   10	Female	75	5		123	87
   11	Female	77	4		139	100
   Total			45

   Source: Prepared by authors

The greater perceived benefit for older adults could be presented as a limitation but also seems to be a specific of the study and therefore findings. As the study population is in heading, abstract and introduction about older adults, it is quite clear that it is the study population that findings are relevant to. It is however excellent to define the findings as specific to the demographic of the study population, therefore avoiding an assumption of defined benefits for other age groups. 

Example: Findings are specific to older adults and should not be assumed as specific benefits for other ages groups, nor benefits as only for this age group.

1. Moved to discussion : The findings presented here are specific to older adults between the ages of 61 and 77 and should not be assumed to apply to other age groups.

Recommendations are clearly included in the article. They could address these limitations as defined by the authors. Examples: include further studies for the same age group, and for different age groups of similar health conditions. And/or for different or same age groups with health conditions as the variable.

1. Added to conclusions: It is recommended that additional studies be included for the same age group and for different age groups with similar health conditions.

Line 161-166: Could be better written to associate air quality with the factors listed and then with noise. The point about noise as associated with air quality indicates that these other factors related to air quality influence noise exposure. Are they, or are other noises and distance from urban noise the reason for reduced noise?

1. In the description of the study area, we included:
2. According to the work done by Díaz, the Los Colomos Urban Forest [15], is a green infrastructure in the city of Guadalajara that is characterized by a peaceful environment, which is essential to reducing stress and providing visitors with energy.
3. The Colomos Forest is an important regulator of air quality, particularly in regard to  particles less than 10 microns, which are among the most prevalent pollutants exceeding the city’s air quality standards. This is mainly attributed to the park´s size, tree density, topographic diversity and the presence of natural springs. These four attributes also mitigate the noise generated by the city's high vehicular traffic.
4. Furthermore, the forest is recognized for serving as a temperature regulator, which is why it is considered a site that mitigates the exposure to risks related to increasingly frequent and intense heat waves in the urban area of Guadalajara.

Line 242-243: 18 participants or 18 records for the 11 participants, or 18 records for # of participants.

1. Corrected: The 45 records total obtained in the study population during the five sessions allowed us to identify 18 records with elevated blood pressure and six with hypertension.

Line 270 - 298:

The discussion explains how findings support existing studies, according to heart rate per minute (not significant) and systolic and diastolic blood pressure (significant). It also and therefore highlights systolic and diastolic blood pressure as significant indicators for cardiovascular effect.

In discussion before or after stating a positive influence, provide written example of why the difference in heart beat per minute and blood pressure is or is not statistically significant with literature support.

1. Added in the discussion because there is no significant difference with respect to heart rate.
2. The failure to find a significant correlation between BFs and heart rate may be attributed to the fact that this study was limited to the month of May.  Previous studies (Huang et al., 2023) have reported significant findings when examining data from different seasons of the year where changes in air quality and atmospheric environment were observed mainly influenced by Volatile Organic Compounds (VOCs) and negative air ions (NAIs).
3. Reference: Huang, R.; Li, A.; Li, Z.; Chen, Z.; Zhou, B.; Wang, G. Adjunctive Therapeutic Effects of Forest Bathing Trips on Geriatric Hypertension: Results from an On-Site Experiment in the Cinnamomum camphora Forest Environment in Four Seasons. Forests 2023,14,75. https://doi.org/10.3390/f14010075

Conclusion

The conclusion could include specifics of the program, location and designed guided walking and sensory plans for the guided walking. That it is important that forest bathing, and forest interactions for health benefit are designed, planned and guided.

1. Added to conclusions: A guided Forest Baths intervention program in five sessions, designed for older adults, conducted in an urban forest which has a history of over a century, located within the city limits and characterized by permeable soils, significant biodiversity and a sizeable area, as the one undertaken in this study, following the method proposed by Forest Therapy Hub (2023), is recommended as an option for healthy life habits in large cities to reduce blood pressure in older adults.  It enables states of relaxation and emotional experiences that have a positive and significant potential to reduce blood pressure in individuals at risk.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Summary
This paper provides evidence that exposure to a forest environment in a city has physiological benefits in terms of reducing high systolic blood pressure and diastolic hypertension. No effect on heart rate was detected.

Assessment

The study provides a case study of the benefits of forest bathing (FB) but is rather limited in the number of participants, the length of the study and the physiological measurements taken. Although significance tests were taken on the effects of FB, the numbers of participants were low. With women constituting 82% of the participants, it is unfortunate that there were so few men. While the sessions took two hours on successive days, no information is given of how far the participants had to travel to get to the forest park and whether two hours is sufficient to gain the benefits of the forest environment.

I note from Google Earth that the Los Colomos Urban Forest in Guadalajara is heavily indented, surrounded by roads, sporting grounds and housing and it would seem difficult to feel distant from such an urban setting. Are the benefits of FB in this study limited by the choice of location in which to test it?

The study findings are probably reproducible, given similar number of participants and location, however increasing the number of participants and finding a more suitable location would be recommended. The paper recognised the number of participants as a limitation (Line 121), a statement that should be located in the Discussion section rather than at the beginning of the paper.

A map showing the location of Guadalajara and the Los Colomos Urban Forest within it would be useful. An aerial photo of the park, such as from Google Earth should also be included. The tables are clear though rather spaced out. Note also the specific comments below on Tables 1, 3 and 4. Figure 1 does not add anything of substance to the paper and should be deleted.

The discussion section includes the statement “The implementation of Forest Bathing could be considered as a comprehensive intervention to improve cardiovascular health in older adults.” This should be placed in the Conclusions and further elaborated upon in terms of the health services. Some doctors for example have advocated giving a “nature pill” to get people to spend more time outdoors in natural settings. The statement in the conclusions about the results should be placed in the Discussion section.

While the paper is scientifically sound and the experimental design is appropriate to test the hypothesis, there are limitations in the paper in terms of the number of participants, the location of the study, and the preponderance of women.

The authors state that the data are available on request, and that there was no conflict of interest.

Specific Comments

Line 73 “(landscape, colors, sounds, textures, aromas, flavors, movement, etc.)” repeats much of Line 53-54 “biodiversity, landscapes, textures, colors, sounds, aromas, water and wind”.

Line 74-75 “that leads people to generate physiological, psychological and social benefits from nature.” I don’t think people generate these benefits, they receive these benefits. “from which people receive physiological, psychological and social benefits from nature.”

Table 1. I suggest that a division be made on the basis of gender (male, female) for each of the categories – age, chronic diseases, medication etc,

Line 163 “regulates air quality in an important way since it reduces noise” There is no connection between air quality and noise.

Table 3 Replace the heading ‘Statistician’ with ‘Statistic’.

Table 4 The table refers to “session 1 and session 5” but there were 6 sessions with the first session being introductory. Should this refer to “session 2 and session 6” or “session 1 and session 6”?

Author Response

The study provides a case study of the benefits of forest bathing (FB) but is rather limited in the number of participants, the length of the study and the physiological measurements taken. Although significance tests were taken on the effects of FB, the numbers of participants were low. With women constituting 82% of the participants, it is unfortunate that there were so few men. While the sessions took two hours on successive days, no information is given of how far the participants had to travel to get to the forest park and whether two hours is sufficient to gain the benefits of the forest environment.

1. About the two-hour duration time:
2. The two-hour duration was designed based on a review of the literature which indicates  that spending at least 120 minutes per week in nature is associated with good health and well-being (White et al, 2019), and that there is no additional benefit to spending more than 200 to 300 minutes per week in nature.
3. Reference: White, M.P., Alcock, I., Grellier, J.,  Wheeler, B. W., Hartig, T., Warber, S. L., Bone, A., Depledge, M.H. & Fleming, L. E. Spending at least 120 minutes a week in nature is associated with good health and wellbeing. Scientific Reports, 2019, 9, 7730, 1- 11. https://doi.org/10.1038/s41598-019-44097-3

I note from Google Earth that the Los Colomos Urban Forest in Guadalajara is heavily indented, surrounded by roads, sporting grounds and housing and it would seem difficult to feel distant from such an urban setting. Are the benefits of FB in this study limited by the choice of location in which to test it?

1. On the question of whether the benefits are limited by the choice of location:
2. The findings presented here are representative of an urban park of nearly 100 hectares, with diverse access roads and public transportation and which is part of the city’s history.  The park has a diverse range of reliefs, plants and animals, as well as the presence of water, enabling the visitor to detach from the stressful dynamics of the city.

The study findings are probably reproducible, given similar number of participants and location, however increasing the number of participants and finding a more suitable location would be recommended. The paper recognised the number of participants as a limitation (Line 121), a statement that should be located in the Discussion section rather than at the beginning of the paper.

1. Limitations of the work were moved from Introduction to Discussion, adding the preponderance of women as another limitation.
2. We consider as limitations of this work the size of the study population and the peculiarities of working with older adults, recognizing that they may have a greater perceived benefit from this practice,

A map showing the location of Guadalajara and the Los Colomos Urban Forest within it would be useful. An aerial photo of the park, such as from Google Earth should also be included.

1. Figure 1. Location of the Los Colomos urban forest

 Figure 1 does not add anything of substance to the paper and should be deleted.

1. Eliminated Figure 1.

The discussion section includes the statement “The implementation of Forest Bathing could be considered as a comprehensive intervention to improve cardiovascular health in older adults.” This should be placed in the Conclusions

1. Moved to conclusions

 While the paper is scientifically sound and the experimental design is appropriate to test the hypothesis, there are limitations in the paper in terms of the number of participants, the location of the study, and the preponderance of women.

1. A guided FB intervention program in five sessions, designed for older adults, conducted in an urban forest which has a history of over a century, located within the city limits and characterized by permeable soils, significant biodiversity and a sizeable area, as the one undertaken in this study, following the method proposed by Forest Therapy Hub (2023), is recommended as an option for healthy life habits in large cities to reduce blood pressure in older adults.  It enables states of relaxation and emotional experiences that have a positive and significant potential to reduce blood pressure in individuals at risk.

Line 73 “(landscape, colors, sounds, textures, aromas, flavors, movement, etc.)” repeats much of Line 53-54 “biodiversity, landscapes, textures, colors, sounds, aromas, water and wind”.

1. Eliminated: (landscape, colors, sounds, textures, aromas, flavors, movement, etc.)

 Line 74-75 “that leads people to generate physiological, psychological and social benefits from nature.” I don’t think people generate these benefits, they receive these benefits. “from which people receive physiological, psychological and social benefits from nature.

1. Changed generate to receive, and the paragraph now reads: “through the connection with the natural environment that leads people to receive physiological, psychological and social benefits from nature”.   

Table 1. I suggest that a division be made on the basis of gender (male, female) for each of the categories – age, chronic diseases, medication etc,

1. Table 2. Study population and number of records/participant 

2. Participants			Num. of sessions in which he/she participated	Disease that increases the risk of vascular complications	Highest systolic pressure	Highest diastolic pressure
   Nimber	Sex	Age in years			Mm Hg	Mm Hg
   1	Female	61	4		128	87
   2	Female	64	3		125	87
   3	Female	66	5	Diabetes type 2	149	92
   4	Female	67	4		169	97
   5	Female	67	2	Diabetes type 2	140	86
   6	Male	68	5		129	90
   7	Male	68	5	Diabetes type 2	132	87
   8	Female	69	5		123	82
   9	Female	71	3	Diabetes type 2	118	82
   10	Female	75	5		123	87
   11	Female	77	4		139	100
   Total			45

Line 163 “regulates air quality in an important way since it reduces noise” There is no connection between air quality and noise.

1. The Colomos Forest is an important regulator of air quality, particularly in regard to  particles less than 10 microns, which are among the most prevalent pollutants exceeding the city’s air quality standards. This is mainly attributed to the park´s size, tree density, topographic diversity and the presence of natural springs. These four attributes also mitigate the noise generated by the city's high vehicular traffic.

Table 3 Replace the heading ‘Statistician’ with ‘Statistic’.

1. Replaced Statistician’ for ‘Statistic’ in table 4

Table 4 The table refers to “session 1 and session 5” but there were 6 sessions with the first session being introductory. Should this refer to “session 2 and session 6” or “session 1 and session 6”?

1. Table 5’s title mentions:
2. Session 2 and Session 6, with a note stating that session 1 was a welcoming session for participants and to become familiarized with the natural environment.

 

 

 

Author Response File: Author Response.pdf