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Volume 84 | Issue 4 | August 2019 199
Eur. J. Hortic. Sci. 84(4), 199–205 | ISSN 1611-4426 print, 1611-4434 online | https://doi.org/10.17660/eJHS.2019/84.4.1 | © ISHS 2019
Brainwave measurements for lay activities with real and
A. Hassan, Chen Qi bing and Jiang Tao
College of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan, China
Original article German Society for
Horticultural Science
Summary
Objectives – Ornamental plants have a major im-
evidence-based studies are currently available re-
-
mary goal was to determine whether exposure to
real ornamental plants during lay activities has psy-
chophysiological relaxation effects in adults. Meth-
ods – Participants were instructed to perform a hor-
basket) using real ornamental plants or to handle
their psychophysiological responses were compared.
Fifty Chinese females (mean age 20.14± 1.47 years)
participated in this experiment. Blood pressure and
electroencephalography (EEG) were evaluated to de-
termine physiological responses, and the State-Trait
Anxiety Inventory (STAI) was used to measure the
psychological responses. Results – According to the
STAI data, the participants showed lower anxiety lev-
els after performing the horticultural activity than
after performing the control activity. In the EEG eval-
uation, variations in brainwaves were observed after
both activities. Conclusion – In conclusion, horticul-
tural activity using real ornamental plants can pro-
mote psychophysiological relaxation in adults.
Keywords
activity
What is already known on this subject?
• Direct interaction with plants for 15 minutes may
increase positive feelings and reduce stress, as
demonstrated by the semantic differential method
(SDM) and heart rate variability (HRV) techniques in
young male adults in a limited sample.
What are the new findings?
• Contact with real ornamental plants for 12 minutes
may enhance both physiological and psychological
relaxation and reduce negative feelings in adults as
indicated by State-Trait Anxiety Inventory (STAI)
scores and brainwave measurement techniques in
female adults in a large sample.
What is the expected impact on horticulture?
• Due to high academic pressure, stress levels among
university students are increasing. Our study provides
basic knowledge for controlling stress and improving
mental health among modern adults.
al., 2006; St Leger, 2003). Currently, an increasing number
of people live in urban environments and spend more time
indoors, away from nature (Molina and Molina, 2004). Most
importantly, urban lifestyles that include long hours in an
serious effects on communal and personal health and hap-
piness (Kaplan, 1992). Many mental health problems, such
as depression and stress, are believed to manifest due to lack
-
land-Noble et al., 2006). Recent advancements in technology
are also considered challenges because most people spend
their free time engaging in technology-based activities. Many
adults are connected to electronics, such as mobile phones
and tablet devices, and are losing their connection to the
natural environment. Children aged 8 to 18 years show in-
creased time spent engaged in media activities, from approx-
imately 8 hours to nearly 11 hours each day (David-Ferdon
and Kaslow, 2008). However, this wide-spread development
in technology has led to increased stress. The incidence of
anxiety and depression among children (from birth to 12
years of age) and adults (aged 13 to 18 years) is increasing
at an alarming rate. More than 25 percent of adults struggle
with anxiety, and approximately 6 percent of these adults
have a severe anxiety disorder (Merikangas et al., 2010).
Stress has been shown to seriously affect approximately 11
percent of adults by the age of 18 years (Breland-Noble et al.,
2006). Therefore, increasing attention has been directed to-
ward the useful effects of nature-related practices, including
Introduction
Background
Human beings are clearly reliant on nature to meet their
physical, emotional and cognitive needs (Friedmann and
Thomas, 1995; Frumkin, 2001; Katcher and Beck, 1987; Ro-
szak et al., 1995; St Leger, 2003). According to the biophilia
hypothesis (Wilson, 1984), humans have an innate desire
to interact with the natural environment. Furthermore, the
natural environment plays a vital role in health stability, and
theoretical foundations for the positive relationships be-
tween human health and natural environments have been
established. The stress reduction theory (Ulrich et al., 1991)
and the attention recovery theory (Kaplan and Kaplan, 1989;
-
ly facilitate recovery from psychological stress and atten-
mental health remains under investigation by scientists in
many public and private educational institutions (Maller et
Volume 85 | Issue 4 | August 2020 279
Eur. J. Hortic. Sci. 85(4), 279–283 | ISSN 1611-4426 print, 1611-4434 online | https://doi.org/10.17660/eJHS.2020/85.4.9 | © ISHS 2020
Do plants affect brainwaves? Effect of indoor plants in work
environment on mental stress
A. Hassan1, Chen Qibing1, Liu Yinggao2, Jiang Tao3, Guo Li1, Mingyan Jiang1, Li Nian1, Lv Bing-Yang1 and
Liu Shiliang1
1 College of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan, China
2 College of Forestry, Sichuan Agricultural University, Chengdu, Sichuan, China
3 College of Forestry, Guizhou University, Guizhou, China
Original article
Introduction
Plants are most commonly used for indoor recreation-
al and aesthetic purposes; however, experiments assessing
human behavior in response to certain types of indoor or-
-
fects on physiological and mental health are limited. Plants
may lower air contaminants, including nitrogen dioxide,
formaldehyde, carbon monoxide, benzene, and trichloro-
ethylene (Stec et al., 2005). Furthermore, a green vegetative
environment can reduce psycho-physiological stress and
anxiety levels (Ulrich, 1979; Ulrich et al., 1993). Important-
ly, heavy workloads and long working hours increase the
daily discomfort in individuals who live and work in mod-
ern buildings. One of the factors for this discomfort may be
gains for family and for a better quality of life (Skov et al.,
for individuals working in modern buildings. Individuals
Summary
Objectives
-
-
Meth-
ods
Results-
for tasks performed in the presence of plants than
Conclusions
Keywords
technology
What is already known on this subject?
• The presence of natural vegetation can reduce stress
and anxiety in individuals.
What are the new findings?
• Presence of indoor plants in workplace enhanced
brainwave activity and reduced anxiety compared
with task completion in the absence of plants.
What is the expected impact on horticulture?
• Stress levels among Chinese students are high because
of excessive computer use. Horticultural therapy
provides a way to eliminate this stress.
working in rooms with interior plants have demonstrated
full recovery from anxiety and stress symptoms (Lohr et al.,
1996). Moreover, there is a strong link between response to
pain and exposure to plants in humans (Hartig et al., 1991;
Ulrich, 1984); hospital windows with a view of plants can
reduce pain in patients as compared to that with a view of a
brick wall with no plants. These studies indicate that more
link between pain and stress reduction. Stress refers to an
organism’s response to a threat, challenge, or physical/psy-
chological barrier (stressor). Although some types of stress
can be favorable, such as those during certain educational
settings (Linn and Zeppa, 1984), unfavorable stress has been
associated with sleep disorders, anxiety, interpersonal con-
reduced concentration, and academic dishonesty (Flaherty
and Richman, 1993). Favorable stress can promote learn-
ing, whereas unfavorable stress suppresses it (Solomon et
al., 1991). In addition, unfavorable stress has been linked
to the inhibition of personal development and academic
achievement (Solomon et al., 1991). Electroencephalogra-
phy (EEG) is a non-invasive, inexpensive instrument to re-
cord neural activity in the form of electrical waves (Lei and
Roetting, 2011). Subsequently, changes in EEG patterns are
associated with neurophysiological responses to external
stimuli. Some EEG studies have measured the neurophysio-
logical response in certain environments to various sensory
inputs, including hearing, taste, vision, and smell (Ajiro et al.,
2009). Additional new approaches using EEG have included
experiments assessing human reactions to plants (Ajiro et
al., 2009). Further, EEG has been used in the management
of stress or anxiety issues (Angelucci et al., 2014) and is
German Society for
Horticultural Science
Original Paper
I
Indoor
and
and B
uilt
uilt
Environment
Effects of different landscape visual
stimuli on psychophysiological
responses in Chinese students
Mingyan Jiang
1
, Ahmad Hassan
1
, Qibing Chen
1
and
Yinggao Liu
2
Abstract
Human–plant interactions have positive effects on human health. However, the effects of plants and the
environment on psychophysiological responses have not been thoroughly explored. This study examined
the physiological (electroencephalography (EEG)) and psychological (the semantic differential method
(SDM) and State-Trait Anxiety Inventory (STAI)) responses of adults viewing different landscape pictures.
The physiological responses of 50 Chinese students were recorded by measuring blood pressure and
EEG, and psychological responses were measured using the STAI and SDM. The following treatments
were assessed: (1) urban city traffic photographs (control), T0; (2) garden landscape photographs, T1; (3)
natural scenery landscape photographs, T2; (4) forest landscape photographs, T3 and (5) city landscape
photographs, T4. Students’ blood pressure was lowered after visual stimulation with different landscape
pictures than with the control. In the (SDM) evaluation, students felt more natural, relaxed and comfort-
able after viewing landscape pictures and had low anxiety scores. EEG results showed higher alpha, beta,
delta, theta and gamma frequencies after visual stimulation with landscape pictures than with the control.
In conclusion, different landscape pictures have psychophysiological relaxation effects on adults.
Keywords
Visual landscape, Blood pressure, Brainwaves, Alpha brainwave, Beta brainwave
Accepted: 28 July 2019
Introduction
Urban environmental quality contributes to human
health and well-being. Health promoting elements in
urban environments, for example, greenery, are
thought to help urban dwellers feel better and cope
with daily stresses.
1–4
At present, urban green places
are under pressure due to the challenge of providing
quality living environments mainly in response to rap-
idly increasing urbanization. Furthermore, in terms of
the urban development of natural landscapes, the ben-
efits to urban dwellers have not been completely estab-
lished. Consequently, urban greenscapes are difficult to
defend when faced with various land use interests.
5
In
developed urban areas, long-lasting and severe stress,
as well as inadequate stress recovery, is an important
issue with persistent health effects.
6,7
Stress is a major
threat to human health and is responsible for many
health-related issues, such as gastroenterological, car-
diovascular, neurological and immunological diseases,
as well as burnout syndrome.
8
In most European coun-
tries, major occupational health problems are related to
musculoskeletal issues (59.8%) or caused by depression
or anxiety (13.7%) or stress.
9
Thus, controlling stress is
1
College of Landscape Architecture, Sichuan Agricultural
University, Chengdu, Sichuan, China
2
College of Forestry, Sichuan Agricultural University, Chengdu,
Sichuan, China
Corresponding author:
Ahmad Hassan, College of Landscape Architecture, Sichuan
Agricultural University, Chengdu, Sichuan 611130, China.
Emails: ahmaduaf1416@gmail.com; cqb@sicau.edu.cn;
499130793@qq.com
Indoor and Built Environment
0(0) 1–11
!The Author(s) 2019
Article reuse guidelines:
sagepub.com/journals-
permissions
DOI: 10.1177/1420326X19870578
journals.sagepub.com/home/ibe
Research Article
Psychological and Physiological Relaxation Induced
by Nature-Working with Ornamental Plants
Jiang Tao,1 Ahmad Hassan ,2 Chen Qibing ,2 Liu Yinggao ,3 Guo Li ,2 Mingyan Jiang,2
Deng Li,2 Li Nian,2 Lv Bing-Yang,2 and Zhong Ziqin4
1College of Forestry, Guizhou University, Guiyang, Guizhou 550025, China
2College of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
3College of Forestry, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
4College of Horticultural Sciences, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
Correspondence should be addressed to Ahmad Hassan; ahmaduaf1416@gmail.com, Chen Qibing; 2948642202@qq.com, and Liu
Yinggao; 499130793@qq.com
Received 24 February 2019; Accepted 30 September 2019; Published 7 March 2020
Academic Editor: Cengiz Çinar
Copyright © 2020 Jiang Tao et al. is is an open access article distributed under the Creative Commons Attribution License, which
permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Objective. Nature has a significant impact on general well-being. However, till date, little psychophysiological evidence is available on
the benefits of nature-based activities in adults. e primary goal of this study was to determine the physiological and psychological
benefits of horticultural activity in adults. e participants were instructed to perform the making of a flower basket (horticultural
activity) and a computer task (i.e., control activity) was compared. Methods. A total of 40 Chinese females (mean age 22.2 ± 0.9 years)
participated in this experiment. e Blood pressure, the State-Trait Anxiety Inventory (STAI), and the electroencephalograms (EEGs)
were used to measure the participants’ psychophysiological responses. Results. Analysis of the STAI data showed a lower anxiety
score aer performing the horticultural activity than aer performing the control activity. Furthermore, in the EEG evaluation,
variations in the brainwaves were observed aer both activities. Conclusions. e study results suggest that horticultural activity
induced physiological and psychological relaxation in adults.
1. Introduction
Humans are considered to be entirely dependent on nature
for their emotional, cognitive, and physical needs [1–3].
However, whether nature is beneficial for mental health
remains under investigation by scientists at many educational
institutions [4]. In the 1970s, scholars investigated the psycho-
logical role of nature applied psychometric measures to
explore the eco-friendly perceptions and cognitive states of
human subjects in natural surroundings [5, 6]. However, in
the 1970s, some scholars began to examine the effects of nature
on the participants’ psychological and “biological responses
to various environments” [7–10]. Studies have found that con-
tact with plants can have both psychological and physiological
benefits [7, 11, 12]. Furthermore, involvement in nature and/
or wilderness settings can help with stress management and
can be healing [13]. In addition, humans who spend time in
natural environments are healthier and more mentally active
[14]. Currently, people are increasingly living in urban places
and spending more time indoors away from nature [15]. Many
mental health problems, such as depression and stress, are
believed to occur from a lack of exposure to nature or from
living in an artificial world [16]. Furthermore, recent advance-
ments in technology are also considered to be hurdles because
most adult populations are connected to electronics, such as
mobile phones and tablet devices, and they are losing their
connection to the natural environment. Moreover, this dis-
persal of information technology causes considerable stress,
such as technostress [17], which is a new disease of adaptation
that is caused by an inability to cope with new computer tech-
nologies in a healthy way. erefore, there is a growing need
to reconnect adults to the healing powers of natural environ-
ments. People also receive benefits from plants in natural or
vegetative surroundings in both direct and indirect ways such
as lower blood pressure, increased productivity and attentive-
ness, reduced mental fatigue, and stress and fewer reports of
Hindawi
Discrete Dynamics in Nature and Society
Volume 2020, Article ID 6784512, 7 pages
https://doi.org/10.1155/2020/6784512
Research Article
Effects of Walking in Bamboo Forest and City Environments on
Brainwave Activity in Young Adults
Ahmad Hassan, Jiang Tao, Guo Li, Mingyan Jiang, Liu Aii, Jiang Zhihui,
Liu Zongfang, and Chen Qibing
College of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
Correspondence should be addressed to Chen Qibing; cqb@sicau.edu.cn
Received 10 June 2017; Revised 23 November 2017; Accepted 2 January 2018; Published 11 February 2018
Academic Editor: Loren Toussaint
Copyright © 2018 Ahmad Hassan et al. is is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Background. In Japan, “Shinrin-yoku” or forest bathing (spending time in forests) is a major practice used for relaxation. However,
its eects on promoting human mental health are still under consideration. e objective of this study was to investigate the
physiological and psychological relaxation eects of forest walking on adults. Sixty participants (50% males; 50% females) were
trained to walk 15-minute predetermined courses in a bamboo forest and a city area (control). e length of the courses was
the same to allow comparison of the eects of both environments. Blood pressure and EEG results were measured to assess the
physiological responses and the semantic dierential method (SDM) and STAI were used to study the psychological responses.
Blood pressure was signicantly decreased and variation in brain activity was observed in both environments. e results of the two
questionnaires indicated that walking in the bamboo forest improves mood and reduces anxiety. Moreover, the mean meditation
and attention scores were signicantly increased aer walking in a bamboo forest. e results of the physiological and psychological
measurements indicate the relaxing eects of walking in a bamboo forest on adults.
1. Introduction
Stress is a main public health concern that is associated with
psychological health problems, cardiovascular problems,
burnout syndrome, and neurological and immunological
diseases [1]. In modern urban societies, long-term stress
and inadequate recovery from stress are documented as an
increasing problem and have long-term eects on health
[2, 3]. Additionally, psychosocial issues play vital roles in
the development of musculoskeletal pain. Existing health-
care practices, however, are expensive and oen emphasize
treating stress-related illnesses, instead of stopping them.
ese ndings indicate that stress control is a major factor in
maintaining good health and alleviating stress-related disease
in urban societies. Researchers are increasingly interested in
whether nature may support both the alleviation of illnesses
that are facilitated by mental processes, such as stress, and
the cure of stress-related diseases, such as depression and
fatigue. Many studies from Asia, Europe, and North Amer-
icahavereportedthatcomparedwithcitysurroundings,
natural surroundings improve human concentration and
performance [4–6] as well as mood states [7, 8]. Furthermore,
widespread observations suggest that natural surroundings
canboosthumanhealth[9].Livecontactwithplantsand
trees in urban parks or gardens has been shown to relax
andcalmpeople[10–13].InJapan,“Shinrin-yoku,”orforest
bathing, is dened as entering a forest environment. e
practice is currently receiving greater attention as a means
of relaxation and stress reduction. In “Shinrin-yoku” activ-
ities performed in forest environments are used to increase
psychophysiological health [14]. Furthermore, walking, the
most common physical activity, is becoming increasingly
important in the prevention of diseases [15–17]. A recent
study demonstrated that forest walking can increase self-
rated health issues and tends to minimize psychological stress
in healthy individuals [18]. Additionally, positive mental
benets can be observed with forest walking in individuals
with major depressive symptoms [19]. We have reported
the psychophysiological relaxation eects of “forest bathing”
from the perspective of brain activity and emotions. In
previous studies, psychological responses have been recorded
using the Prole of Mood States (POMS) [20, 21]; however,
Hindawi
Evidence-Based Complementary and Alternative Medicine
Volume 2018, Article ID 9653857, 9 pages
https://doi.org/10.1155/2018/9653857
Brain and Behavior. 2019;00:e01359.
|
1 of 6
https://doi.org/10.1002/brb3.1359
wileyonlinelibrary.com/journal/brb3
1 | BACKGROUND
The aging population is increasing in number worldwide. Almost
one in nine people are aged 60 years or above. It is expected
that by 2050, the ratio will reach one in every five people (Chan
et al., 2017). According to a recent UN repor t, China is leading in
this aging trend, whereby more than 30% of the total population
will likely be aged 60 years or greater by 2050 (Banister, Bloom,
& Rosenberg, 2012). The elderly population has a relatively high
risk of poor mental health, primarily because of social isolation
(Cornwell & Waite, 2009). Therefore, in recent years, there has
been increasing demand for research into nature‐based therapies
that utilize the beneficial effects of the natural environment on
well‐being; one example is horticultural therapy. Horticultural
therapy is an increasingly popular technique that utilizes various
activities, such as viewing, touching, smelling, and tasting, to meet
the specific rehabilitative or therapeutic goals of its participants.
Among older adult s, it is a popular leisure‐time activity that is as‐
sociated with positive health ef fect s, such as a reduction in anger
(Hartig, Evans, Jamner, Davis, & Gärling, 2003). This may be be‐
cause of the calming effect of nature, as reflected in stress miti‐
gation and recovery of directed attention fatigue (Kaplan, 1995).
Received:28February2019
|
Revised:24May2019
|
Accepted:24June2019
DOI: 10.100 2/brb3.1359
ORIGINAL RESEARCH
Psychological and physiological effects of viewing a money
plant by older adults
AhmadHassan1 |ChenQibing1 | Liu Yinggao2 | Jiang Tao3 |GuoLi1 |
Mingyan Jiang1 |LiNian1 |LvBing‐Yang1
This is an op en access article under t he terms of t he Creative Commons Attribution License, which permits use, distribution and reproduct ion in any me dium,
provide d the orig inal work is proper ly cited.
© 2019 The Auth ors. Brain and Behavior published by Wil ey Periodicals, Inc.
1College of Landscape Architecture, Sichuan
Agricultural University, Chengdu, China
2College of Forestry, Sichuan Agricultural
University, Chengdu, China
3College of Forestr y, Guizhou U niversi ty,
Guizhou, China
Correspondence
Chen Qibing and Ah mad Hass an, Coll ege
of Landscape Architecture, Sichuan
Agricultural University, Chengdu, Sichuan
611130, Chi na.
Emails:294 8642202@qq.com(CQ )and
ahmaduaf1416@gmail.com(AH)
Liu Ying gao, College of Fore stry, Sichuan
Agricultural University, Chengdu, Sichuan
611130, Chi na.
Email:499130793@qq.com
Funding information
This stu dy was spo nsored (National Natural
Science Foundati on of China grant no.
31570700).
Abstract
Background:Obser ving plants can induce neurophysiological responses that can al‐
leviate stress and reduce anxiety. However, few studies have examined such effects
in older adults.
Methods:The physiological and psychological effects of observing nature (visual ob‐
servation of a money plant) on 50 older Chinese women (age range: 58–90 years, SD:
8.5 years) were investigated. The participants observed a healthy money plant in a
planter for 5 min; the lack of presence of a plant was used as a control. Physiological
measurements were assessed using electroencephalography, and the STAI was used
as a psychological assessment.
Results: After a 5‐min observation of a money plant as compared with the control
condition, systolic blood pressure significantly decreased, variations in both high
alpha and high beta brainwaves were found, and psychological measurements re‐
vealed lower anxiety scores.
Conclusions:Our findings indicate that viewing a money plant for 5 min may enhance
both psychological and physiological relaxation in older adults.
KEY WORDS
blood pressure, greenery, high beta, money plant
ORIGINAL ARTICLE
EPIDEMIOLOGY, CLINICAL PRACTICE AND HEALTH
Physiological and psychological effects of gardening activity in
older adults
Ahmad Hassan, Chen Qibing and Jiang Tao
College of Landscape Architecture,
Sichuan Agricultural University,
Chengdu, China
Correspondence
Professor Chen Qibing, College of
Landscape Architecture, Sichuan
Agricultural University, Chengdu,
Sichuan 611130, China.
Email: 2948642202@qq.com
Received: 27 October 2017
Revised: 15 February 2018
Accepted: 7 March 2018
Aim: Gardening has long been one of most enjoyable pastimes among older adults.
Whether gardening activities contribute to the well-being of older adults is a major question.
Therefore, the aim of the present study was to clarify the psychophysiological relaxing effects
of gardening activities on older adults living in modern institutional care.
Methods: The study participants were 40 older women aged 79.5 8.09 years (mean
SD). A cross-over study design was used to investigate the physiological and psychological
responses to environments with and without plants. Physiological evaluation was carried out
using blood pressure and electroencephalography, and psychological evaluation was carried
out using the State-Trait Anxiety Inventory and Semantic Differential method.
Results: Blood pressure was significantly lower, and changes in brainwaves were observed.
Psychological responses showed that participants were more “comfortable and relaxed”after
the plant task than after the control task. In addition, total anxiety levels were significantly
lower after carrying out the plant task than after the control task.
Conclusions: Our research suggests that gardening activities might enhance physiological
and psychological relaxation in older adults. Geriatr Gerontol Int 2018; ••:••–••.
Keywords: brainwaves, electroencephalography, gardening.
Introduction
Gardening has long been one of the favorite pastimes among older
adults. However, in modern nursing care for older adults, the
chances for continuing hobbies are rare. Health services have nor-
mally been planned to be effective care surroundings, but these
surroundings are often psychologically problematic for older
adults.
1
The life of older adults in nursing care is often thus
marked by feelings of worthlessness, social isolation and loneli-
ness. An older adult in nursing care can often adopt a static role
as a helpless individual. The skills of the older adults become
weakened, when the surrounding environment accepts them as
debilitated instead of supporting their identity. Can gardening
activities positively affect the nursing care surroundings of older
adults? Gardening, when considered a linkage between humans
and plants, includes psychophysiological activities. The main
theme of gardening is the promotion of living things. Gardening
enables social interaction, creativity and reciprocal exchange com-
munication with other people.
2
It can also create new memories
and meaning for the lives of people living in a nursing home. Gar-
dening activities involve various practices, such as touch, smell
and taste, promoted by a trained psychotherapist to minimize
stress.
3
As mentioned, Kaplan and Kaplan reported stress reduc-
tion resulting from seeing different types of natural environ-
ments.
4
Additionally, other studies have shown stress-reducing
effects by lowering blood pressure and mood improvements
resulting from spending time in a natural environment.
5
An elec-
troencephalography (EEG), which measures brainwave activity, is
ordinarily used in many clinical and research settings because it is
completely fatiguing and not invasive, and the recording instru-
ments are reasonably inexpensive. Subsequently, EEG reactions
show variations in the electrical brainwave activity of the human
brain. There have been many studies on psychological influences
that record the effects of sensory inputs, such taste, smell, hearing
and vision, on EEG activity.
6
Additional current approaches using
EEG are now being measured, including studies on human
interfaces.
6
EEG is another intervention that has recently been
reported for the management of anxiety and stress,
7
and is helpful
for the management of various mental diagnoses and brain func-
tions. EEG is the most accepted and investigated method of stress
measurement by brain activity. De Waard in 1996 explained an
EEG as “a recording of electrical brain activity made from the
skull.”EEG frequencies are normally divided into four groups:
alpha waves 8–13 Hz, beta waves >13 Hz, delta waves equal to
4 Hz and theta waves 4–8 Hz. East (2000) supplements an extra
band, ultra beta, from 31 to 42 Hz. When there is an increase in
mental stress or workload, the EEG shows that the alpha waves
vanish and are exchanged by beta waves.
7
Usually, as mental stress
or workload increase, alpha waves decrease and theta waves are
enhanced.
8
Beta waves were related to variations in difficulty. In
1996, Brookings et al. used EEG to investigate the relative effects
of stress or workload variables that are not identified by other
indexes. It is well known that human (EEG) activity is liable to
alteration during exposure to outdoor environments. Thus, EEG
is an excellent neurophysiological calculating instrument to show
brain function or brain state.
8
Most studies have investigated the
psychological effects of plants on humans using different indexes.
Researchers have also begun to investigate the effects of plants on
human physiological responses, such as blood pressure, galvanic
skin response EEG, heart rate, electromyography and psychologi-
cal responses, including the Profile of Mood States and the
State-Trait Anxiety Inventory (STAI).
9
However, the Semantic
Differential method (SDM) is seldom used. Furthermore, the indi-
vidual effects of plant activity on human comfort have not been
scientifically investigated. In addition, no studies have examined
the effects on brainwaves of feelings of relaxation and brain func-
tions in older adults. There is a growing need for a thorough
understanding of the mechanism by which plants affect the
human brain. Therefore, the present study aimed to actively
examine both psychological and physiological responses in trans-
planting tasks with and without plants by recording blood
pressure, EEG and emotional responses in older adults.
1|© 2018 Japan Geriatrics Society
DOI: 10.1111/ggi.13327
Hypertension Research
https://doi.org/10.1038/s41440-019-0209-7
CORRESPONDENCE
Better mind, better work: effects of plants on adolescent mental
stress as measured by EEG
Ahmad Hassan1●Jiang Tao2●Chen Qi Bing1●Liu Yinggao3●Guo Li1●Mingyan Jiang1●Li Nian1●Lv Bing-Yang1
Received: 9 December 2018 / Revised: 18 December 2018 / Accepted: 19 December 2018
© The Japanese Society of Hypertension 2019
Introduction
Educational stressors are a natural part of school life and
they affect a scholar’s academic achievement and mental
health. In Chinese culture, educational stress is surprisingly
serious because Chinese youth are expected to pursue
educational success to achieve family pride, social mobi-
lity, and respect [1], resulting in extremely high educational
demands and extra pressure on middle and high school
adults [2]. Few studies have examined educational stress
among Chinese students [2–7]. Increasing attention has
been paid to the benefits of plant activities, including
horticultural or gardening activities, which are considered
to be supportive for health [8]. However, to date, no studies
have been conducted using electroencephalography (EEG)
to assess the consistency of the positive effects of gar-
dening on health among young adults. Therefore, the goal
of this research was to determine the physiological and
psychological relaxing effects of gardening activities on
university students.
Methods
Participants
We hired forty healthy Chinese adult males and females
(mean age 19.3 ± 1.3 SD) from Sichuan Agricultural Uni-
versity. The use of alcoholic beverages and other brain
affecting drugs was strictly prohibited throughout the
experiment. Written informed consent was obtained from
each subject after a full explanation of the research meth-
ods. This work was approved by the local ethics committee
at the College of Landscape Architecture, Sichuan Agri-
cultural University, China.
Materials and methods
Horticultural activity consisted of transplanting common
indoor plant using real soil for 10 min while completing a
written task using a computer; these activities represented
a 10-min common horticultural physical task and a control
task, respectively, as shown in Fig. 1. The experiment
was performed at a large table, the sides of which were
covered with black paper. The temperature, room humidity
and luminance were consistently maintained at 21 °C,
56 and 500 lux, respectively. Students were randomly
divided into two groups: A and B. The members of group A
(N=20) performed the control task, and those in group B
(N=20) performed the horticultural task. Both activities
were performed individually in a standing position for
10 min.
Measurements and data recording
A NeuroSky MindWave EEG headset was attached to the
participants’head in the waiting room before moving to the
experimental room. After a 5-min rest in a seated position,
the participants performed the given tasks, that is, trans-
planting the plants or performing a computer task, for 10 min.
*Ahmad Hassan
ahmaduaf1416@gmail.com
*Chen Qi Bing
cqb@sicau.edu.cn
*Liu Yinggao
499130793@qq.com
1College of Landscape Architecture, Sichuan Agricultural
University, Chengdu, Sichuan 611130, China
2College of Forestry, Guizhou University, Huaxi, Guiyang 550025,
China
3College of Forestry, Sichuan Agricultural University,
Chengdu, Sichuan 611130, China
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1234567890();,:
HORTSCIENCE 53(1):104–109. 2018. https://doi.org/10.21273/HORTSCI12447-17
Effects of Plant Activity on Mental
Stress in Young Adults
Ahmad Hassan, Chen Qibing
1
, Jiang Tao, Lv Bing-Yang, Li Nian,
Shu Li, Li Yu Tng, Jun Zhuo Li, and Shang Guan Ziyue
College of Landscape Architecture, Sichuan Agricultural University, Chengdu,
Sichuan 611130, China
Muhammad Sohaib Tahir
School of Electronics, Information and Electrical Engineering, Shanghai
Jiao Tong University, Shanghai 201100, China
Additional index words. horticultural, technology, blood pressure, brainwaves
Abstract. Advancements in electronic devices have led to increases in mental stress in
modern adults, and removing this stress is crucial for mental health. The purpose of this
study is to examine the psychophysiological benefits of contact with indoor plants. The
effects of transplanting plants (horticultural activity) and work on a mobile phone
(control activity) were assessed by blood pressure measurement, electroencephalography
(EEG), the semantic differential method (SDM), and the State-Trait Anxiety Inventory
(STAI). The SDM data showed that the subjects felt more relaxed, comfortable and
natural, and experienced lower anxiety after the transplantation of plants than the
control group. Participant’s total alpha and beta wave mean values increased over time
during the transplantation task but decreased at the end of the control task. The mean
meditation score was significantly higher after transplanting plants. Our study results
indicate that contact with plants may minimize mental stress.
The human relationship with nature is
profoundly complex (Heynen et al., 2006;
Jackson, 2003; Kahn, 2005; Kellert, 2004;
Kibert, 1999; Miller, 2005) and therefore
difficult to understand. However, extraordi-
nary psychological, ecological, biological,
and psychiatric research on this relationship
has recently been performed. Many scientists
have concluded that humans depend on
nature for their physical, spiritual, psycho-
logical, and emotional needs (Friedmann and
Thomas, 1995; Frumkin, 2001; Katcher and
Beck, 1987; Roszak et al., 1995; St Leger,
2003; Wilson, 1984). Recent studies have
reported that urban environments are unsuit-
able locations for humans (Bagot, 2005;
Kellert, 1993; van den Berg et al., 2007).
Most importantly, modern social environ-
ments have changed from the outdoors to
indoors. More than 95% of an individual’s
daily activities occur indoors (Lee et al.,
2015). Furthermore, developments in elec-
tronic technology have made it attractive for
people to connect and remain connected to a
machine environment. However, rapid techno-
logical developments have resulted in a new
era with fewer ‘‘green’’ and more artificial
surroundings. The widespread use of technol-
ogy is associated with psychiatric comorbid-
ities including internet addiction, depression,
anxiety, and attention deficit and hyperac-
tivity disorder (ADHD) in humans (Ho et al.,
2014). In addition, the widespread use of
mobile phones among younger generations
has opened the door to new lifestyles and
cultural pride (Reyns et al., 2013). Most
college students spend their time studying
online. Internet or online learning has be-
come an indispensable tool for university
students. The pooled prevalence of internet
addiction among university students is 5
times that in the general population (Zhang
et al., 2017a). Previous studies have reported
that excessive mobile phone usage could
affect the brain and its normal activities
(Imamura et al., 2009) and could increase
the risk of internet addiction (Lai et al.,
2013). Internet addictive behavior is common
among adolescents worldwide. In Asia, the
overall prevalence of smartphone ownership
by adolescents is 62%, ranging from 41% in
China to 84% in South Korea (Mak et al.,
2014b). Participation in online gaming
ranges from 11% in China to 39% in Japan
(Mak et al., 2014b). The prevalence rates of
problematic internet use and internet addic-
tion among adolescents are highest in
Vietnam (21.2%) (Tran et al., 2017b) and
the Philippines (21%) (Mak et al., 2014b).
Excessive smartphone use and internet ad-
diction are associated with poor health out-
comes (Mak et al., 2014a), a lower quality of
life (Tran et al., 2017b), impaired interper-
sonal relationships (Tran et al., 2017a), and
sleep problems (Zhang et al., 2017b). Males
are more affected than females, and 20% to
25% of these cases relate to the excessive use of
mobile phones (World Health Organization,
2004). Indeed, the stressful and fast-paced
modern lifestyle has strengthened the need
for peaceful greener environments for re-
laxation (Stone, 2006). Although rapidly
advancing technology will likely further
contribute to the negative effects of the
modern lifestyle, human development has
experienced few changes during evolution
over the past 10,000 years. For example, our
genetic makeup has changed by only 0.005%
(Williams and Nesse, 1991). Furthermore,
peaceful green environments may represent
part of the solution to this problem (Bird,
2007; Lee et al., 2009; Wendel et al., 2008).
In recent years, the beneficial effect of green
environments has been identified, and further
environmental studies are under way (Kahn
et al., 2009). Physical interactions with plants
represent an emotional and silent act that can
provide mental stability and comfort in dif-
ferent ways. Interaction with plants can also
promote the health of office workers (Dravigne
et al., 2008) by minimizing psychological stress
(Kaplan, 2001), improving mood (Adachi
et al., 2000; Shibata and Suzuki, 2001; Ulrich,
1981; Ulrich et al., 1991), and increasing mental
efficiency (Cimprich, 1993; Hartig et al., 1991;
Tennessen and Cimprich, 1995).
Basic Knowledge of
Electroencephalography and Brainwaves
In recent decades, neuroscience research
has advanced and can presently provide
a more in-depth understanding of brain ac-
tivity. In 1875, Richard Caton discovered the
presence of electrical currents in the human
brain. In 1924, German scientist Hans Berger
recorded electrical activity in the brain using
EEGs (Teplan, 2002). In 1934, Adrian and
Matthews devised the novel concept, of
human brain waves. During the 1950s,
EEG technology was successfully applied
to all fields of cognitive science, neurology,
and neurosurgery (Ali, 2012). Then, in
1964, Dr. Grey Walter connected electrodes
directly to the motor areas of the human
brain to record brainwave activity. An EEG
is a recording of the electrical activity of the
human brain at the scalp level (Stadelmann
et al., 2013). EEG signals are generated
from hyperpolarizing and depolarizing
postsynaptic potentials in populations of
pyramidal neurons (Jackson and Bolger,
2014; Sowndhararajan and Kim, 2016).
Practical applications of EEGs include re-
cordings of structural brain diseases, brain
death, and dementia. In addition, EEGs are
also used to control psychological disorders.
The NeuroSky MindWave EEG headset is an
innovative technique for recording live human
brain activity. A practical application of this
headset was launched in 2009 to control for
ADHD and stress issues in humans, with
86% accurate results (Mostow et al., 2011).
Brainwaves typically appear during both
resting and active states. Our behaviors,
thoughts, and emotions are reflections of
electrical activity inside the brain. An EEG
measures these electrical changes and pres-
ents them as waves. The EEG signals are
divided into different waves, such as alpha,
beta, delta, theta, and gamma waves in the
frequency ranges of 8–13 Hz, 13–30 Hz, 0–4
Hz, 4–8 Hz, and >30 Hz, respectively(Desai
et al., 2015). Research has shown that
Received for publication 31 Aug. 2017. Accepted
for publication 16 Nov. 2017.
1
Corresponding author. E-mail: cqb@sicau.edu.cn.
104 HORTSCIENCE VOL. 53(1) JANUARY 2018
846 Biomed Environ Sci, 2017; 30(11): 846-850
doi: 10.3967/bes2017.114
*This study was supported by grants from the National Natural Science Foundation of China [grant no. 31570700].
1. College of Landscape Architecture, Sichuan Agricultural University, Chengdu 611130, Sichuan, China; 2. School of
Electronics, Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 201100, China
Letter to the Editor
Psychophysiological Effects of Bamboo
Plants on Adults*
Ahmad Hassan1, CHEN Qi Bing1,#, JIANG Tao1, LYU Bing Yang1, LI Nian1, LI Shu1,
SHANGGUAN Zi Yue1, LI Yun Ting1, JUN Zhou Li1, LUO Qian1, CHEN Xin Yi1,
WANG Yi Yan1, ZENG Cheng Cheng1, YANG Jun1, and Muhammad Sohaib Tahir2
The present study was conducted to clarify the
psychophysiological relaxation effects of viewing
bamboo on university students. Forty healthy
Chinese participants enrolled in this study to clarify
the psychophysiological relaxation effects of viewing
bamboo. The effects of visual stimulation using a
pot both with and without a bamboo were recorded
by measuring the student’s blood pressure, EEG and
STAI. We observed that viewing bamboo plants
resulted in significantly lower systolic (female, P <
0.001; male, P < 0.001; P < 0.05) and diastolic (female,
P < 0.001; male, P < 0.001; P < 0.05) blood
pressures, but no changes in the pulse rate (female,
P = 0.09; male, P = 0.07; P > 0.05) were observed. The
results of the EEG analysis indicated brainwave
variation (all P < 0.05) and lower anxiety scores (P <
0.01) after 3 min of viewing bamboo compared
with the control. These findings indicate that visual
stimulation with bamboo plants induced
psychophysiological relaxation effects on adults.
Currently, social media and mobile phone
devices are popular among teenagers and adults. In
1980, scientists observed that 8- to 18-year-olds
spend a considerable amount of time playing mobile
video games, which resulted in a lack of interest in
nature; therefore, these individuals are rarely
exposed to natural environments[1]. The past decade
has witnessed an increasing number of behavioral
and mental health problems worldwide[2]. According
to the World Health Organization mental health
problems currently constitute 10% of the global
burden of disease[3]. These mental health issues are
rapidly increasing each year and are becoming
significant in all parts of the world. By 2020, mental
illness may account for up to 45% of the total
diseases worldwide[4]. In such a situation, increasing
attention has been focused on the role of natural
environments, such as indoor plants. The effects of
natural elements are increasingly being
acknowledged in stressful locations, such as nursing
homes and hospitals[5]. In these environments and
many other places, such as offices, human contact
with nature is an effective and simple strategy for
improving vitality and relieving stress[5]. People with
access to nearby natural settings have been found to
be healthier overall than people without such access.
Many studies have evaluated the psychological
effects of exposure to flowers; however, the
physiological relaxing effects of viewing bamboo
plants have not been scientifically studied. Bamboo
is a well-known and the most preferred plant in
Chinese landscape design due to its unique beautiful
foliage and fast-growing characteristics. In addition,
bamboo is used for indoor and outdoor decoration
and for recreation purposes in many public and
private parks, schools and nursing homes. The
demand for ornamental bamboo plants has
increased in the field of interior decoration.
Therefore, to clarify the physiological and
psychological effects of viewing bamboo plants on
human comfort, we recruited Chinese male and
female university students.
The experiment was conducted in a conference
room of the College of Landscape Architecture in
March of 2016. The temperature, relative humidity,
and intensity of illumination were maintained at
21 °C, 50%, and 500 lux, respectively. Forty healthy
Chinese students (50% male; 50% female) with
average (mean ± SD) ages of 19.6 ± 1.4 years;
weights 52.0 ± 6.2 kg; and heights 161.2 ± 3.1 cm
from Sichuan Agricultural University, China, were
selected for this trial. All students were non-smokers
and had no previous record of mental disorders.
Before the start of the experiments, the participants
were fully informed of the objective and methods of
the tests, and their consent to undergo these trials