The Effect of Breathing Exercise on Stress Hormones

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RESEARCH ARTICLE
Cyprus J Med Sci 2021;6(Suppl 1):22-27
JOURNAL OF MEDICAL SCIENCES
CYPRUS
DOI: 10.4274/cjms.2021.2020.2390
The Effect of Breathing Exercise on Stress Hormones
Deniz Örün1, Selma Karaca2, Şükran Arıkan2
1Ladik Ahmet Hüdai Imam Hatip Secondary School, Konya, Turkey
2Department of Coaching Education, Selçuk University Faculty of Sport Sciences, Konya, Turkey
ORCID iDs of the authors: D.Ö. 0000-0003-0537-9788; S.K. 0000-0002-0897-6900; Ş.A. 0000-0002-2625-0898.
Abstract
Address for Correspondence: Şükran Arıkan
E-mail : sarikan@selcuk.edu.tr
ORCID ID: 0000-0002-2625-0898
*This research is summarised from Deniz Örün’s master’s thesis.
INTRODUCTION
Life is the period between the first breath and the last one. While
breathing is behavioral and respiration is reflexive; therefore,
breathing and respiration are not the same phenomenon.1
Breathing is based on the energy flow by moving downward/
upward, expanding/narrowing of the chest and abdomen area
in the physical body, and how this flow affects our bodies
physically, mentally and spiritually.2
According to Greek mythology” PNEUMA,” (i.e., breath, is our
primary activity that accompanies us in every aspect of our lives
and enables us to survive healthily for quality life).3 Behavioral
or voluntary control of breathing is located on the cerebral
cortex. While voluntary breathing requires the amount of focus,
attention is not necessary to maintain an automatic (metabolic)
breathing.4 While breathing regulates pH, electrolyte balance,
blood flow, hemoglobin chemistry, and kidney function, it also
has a significant effect on other behaviors such as motivation,
strength, emotion, focus, perception, and memory role.5
Breathing techniques, which are expressed as pranayama applied
in different variations in the form of conscious, intermittent,
nasal, and abdominal breathing where upper, middle, and
Received: 01.07.2020
Accepted: 30.11.2020
BACKGROUND/AIMS: The aim is to determine the acute effects of breathing exercise on stress hormones in young women.
MATERIALS and METHODS: The study was conducted with the voluntary participation of 15 healthy young women who were working as
coaches in the fitness and swimming branches. At the beginning of the study, the body compositions of the participants were determined, and
45-minute natural and connected breathing exercise was applied under the supervision of a breathing coach after having a standard breakfast.
Cortisol and epinephrine hormone analyses from the serums was obtained from the blood samples taken before and after the breathing
exercise were determined through a Chemiluminescence measurement method. Whether the data showed a normal distribution was analyzed
through Kolmogorov-Smirnov test and paired t-test, since parametric test conditions were fulfilled. The relationship between the variables were
determined with a Pearson correlation analysis.
RESULTS: At the end of an acute breathing exercise, a significant decrease was determined in the mean cortisol hormone levels of the participants
(p <0.05). A decrease was observed in the epinephrine hormone levels; however, this change was not found to be statistically significant (p
>0.05). In addition, it was determined that there was a positive and considerably weak insignificant relationship between the mean cortisol and
epinephrine of the participants following the breathing exercise (r=0.039; p >0.05).
CONCLUSION: It could be stated that natural and connected breathing exercise has a reducing effect on stress hormones, and accordingly,
breathing exercises could be used as a relaxation technique.
Keywords: Breathing exercise; cortisol; epinephrine
To cite this article: Örün D, Karaca S, Arıkan Ş. The Effect of Breathing Exercise on Stress Hormones. Cyprus J Med Sci 2021;6(Suppl 1):22-27

Örün et al. The Effect of Breathing Exercise on Stress HormonesCyprus J Med Sci 2021;6(Suppl 1):22-27
23
lower parts of the lung are used.6 Breathing techniques are
regularly applied for relaxation, stress management, control
of psycho-physiological states, and to improve the organ
functions.7 Although there are many sources for stress, it also
varies from individual to individual.8 Psychological studies
revealed breathing practice as an effective non-pharmacological
intervention for emotional improvement including anxiety,
depression, and stress.9 In addition, breathing practices are also
commonly applied in the clinical treatments for mental disorders
such as post-traumatic stress disorder,10 movement disorders,11
phobias, and other stress-related emotional disorders.
Prana is particularly associated with an energy production
processes in the body. There is a direct connection between the
breathing energy and energy release from the body.12 With a
proper breathing, improvements could be experienced in energy
centers of the body. The first energy center is located below the
abdomen near the center of the gravity, and this center controls
vital energy and certain hormones. The proper functioning of
this center strengthens the immune system and increases the
overall life energy.13 Scientists have been reported that the daily
energy needs could be met by taking the deep breaths for 15
mins. However, most people use energy potential in a limited
way because they do not know use the power of breath that will
enable them to achieve these benefits.14 Studies report that slow
and rapid breathing types have different physiological effects in
the healthy subjects.15
Epinephrine and cortisol hormones known as stress hormones,
are secreted by the adrenal glands. Epinephrine hormone
alerts the body by being secreted in the dangerous situations
such as exercise, lack of oxygen, excitement, fear, excessive heat
decrease, anger, and sudden decrease in the blood sugar levels.
The roles of epinephrine are to increase the blood pressure,
heart rate and the blood circulation, depth of respiration,
and blood glucose level. Cortisol hormone, which belongs to
the glucocorticoid class, increases the blood glucose level by
accelerating the synthesis of glucose from the protein and fat in
the liver. It accelerates the burning of triglycerides and causes an
increase in the concentration of free fatty acids in the blood, and
it also has anti-inflammatory effects.16
Stress caused by the physiological or psychological conditions
could be expressed as the sum of reactions of a person to
the various mental and physical difficulties.8 Nervousness,
impatience, anger, hostility, anxiety, panic, restlessness, sadness,
tension, poor memory, difficulty in taking the decisions,
hypersensitivity, change in the sexual life, frequent daydreaming,
frequent repetitions of death and suicidal thoughts, sleep
disorders, depression, increase in the alcohol intake and
substance use, decrease in the self-esteem and productivity are
the psychological symptoms of the stress.17
Stress may have many psychological and physiological causes.
The environment in which we live, our body and even our world
of thoughts could be a trigger factor for stress. However, people
physiologically tend to cope up with the stress and react to it. In
this context, the cortisol hormone plays a very important role
in a stress response. One of the important hormone response
systems to stress is cortisol -hypothalamic-pituitary-adrenal
(HPA) axis, especially the glucocorticoids.18 Within this context,
stressors stimulate cortisol secretion from the adrenal gland by
affecting the hypothalamus. With the mixing of cortisol into the
blood, a stress response occurs in the body.19 Stressors have a
huge impact on the mood, sense of well-being, behavior, and
health. In the presence of a physical or psychological threat,
cortisol levels fluctuate to provide the energy needed to cope up
with the stress-inducing stimuli or escape danger.20
Stress in daily life could cause physical, emotional, behavioral,
and psychological problems as well as chronic illness. Therefore,
it is very important for individuals to learn how to live with stress,
and to know how to manage the stress to minimize its negative
effects. In the study, answers to the questions such as “what
is the effect of breathing exercise on stress hormones,” “Does
the stress hormone level decrease with breathing exercise?”
were sought. The limited number of studies in the literature
conducted on how breathing exercises affect the stress hormone
levels motivated us to carry out this study. This research aimed
to determine the acute effects of breathing exercises applied to
young women on epinephrine and cortisol hormones.
MATERIALS AND METHODS
Research Group
A total of 15 healthy and voluntary young women aged between
20−35 and working as coaches in the different branches
in Konya province, Selçuklu Municipality Social Facilities
participated in this research. Prior to the study, the subjects were
informed about the study and their written informed consents
to participate in the research were obtained. The questionnaire
prepared by the researcher was applied to determine the
demographic characteristics, physical activity levels, and general
health conditions of the participants. For this study, approval
was obtained from Selçuk University Faculty of Sports Sciences
Non-Interventional Clinical Research Ethics Committee on
December 20, 2018.
Inclusion criteria: Having no health problems that would
prevent the participant from doing breathing exercises. Being
in the age range of 20−35. Exclusion criteria: Having a systemic
pathology. Using medication/drugs that may affect the hormone
levels.
General Design of the Research
All measurements and breathing exercise were made on January
23, 2019 at the Selçuklu Municipality Gazalya Hatun Social
Facility. Body composition measurements of the subjects were
performed after a standard breakfast while the blood samples

Örün et al. The Effect of Breathing Exercise on Stress Hormones Cyprus J Med Sci 2021;6(Suppl 1):22-27
24
were taken before and after the acute exercise under the equal
conditions. To reveal the effect of an exercise on biochemical
variables, subjects were warned not to perform heavy physical
activities at least 48 hours before, and not to use any drug or
liquid food that could affect the values.
Determination of Body Composition
The body weights (kg) of the subjects were measured with Tanita
device and their heights (cm) were measured with a metal meter
with 0.01 cm precision. Participants’ body mass index (BMI)
was calculated by dividing the body weight (kg) in the square
of height (m).21 Participants’ fat mass, lean body mass, and fat
percentage values were measured with BC-418 MA model Tanita
device (1-14-2, Maeno-cho, İtabashi-ku, Tokyo, Japan) through
the bio-electrical impedance analyzer technique.
Breathing Exercise
One week before the acute breathing exercise planned for
the research, the participants were informed by a breathing
coach who had received the training on natural and connected
breathing, and a practice session was performed to apply the
technique correctly. One week after this application, all the
participants were subjected to a breathing session on the same
day and at the same time. Breathing session was started after
the participants were in the sitting position with their soles on
the grounds, knees bent, and bodies back at a 45º angle. With
the guidance of the coach, the participants were enabled to
stay in a natural and connected breathing without a break in
an uninterrupted and continuous way. The participants were
enabled to breathe through the mouth for 45 mins by using the
diaphragm and chest, respectively.
Biochemical Blood Analyses
All participants of the research were asked to have a light
standard breakfast at least 2 hours before coming for the exercise.
Blood samples were taken from the forearm elbow vein into the
vacutainer blood collection tubes with a gel and anticoagulant
(6 cc) by the health personnel at 08:00 a.m. before and after the
breathing exercise. Blood samples were centrifuged at + 4ºC and
4,000 rpm for 10 mins and their serums were obtained, and they
were frozen at -20 ºC until the analyses is being done. From the
serum samples, cortisol and epinephrine hormone levels were
determined with Chemiluminescence measurement method in
Abbott Architect I2000 analyzer (Abbott Labs, Chicago, Illinois,
USA) and epinephrine hormone levels were determined with the
same method but in Shimadzu LC-20A HPLC device (Shimadzu
Corp, Kyoto, Japan).
Statistical Analysis
SPSS 22.0 (SPSS Inc., Chicago, IL, USA) packaged program was used
in the analysis of the data. Arithmetic means and standard error
mean of all the variables obtained in the study were calculated.
Kolmogorov-Simirnov test was used to determine whether the
data showed a normal distribution. As a result of the test, it was
determined that the data showed a normal distribution and
paired t-test was applied to reveal the differences between the
measurements performed on the same group at two different times.
The relationship between the variables was determined through
Pearson correlation analysis and the results were evaluated at 95%
confidence interval and p <0.05 significance level.
RESULTS
The mean age of the participants was found to be 29.06±4.26
years, height 163.66±3.81 cm, body weight 54.98±4.97 kg,
fat percentage 24.20±4.23, and mean BMI 20.55±1.78 kg/m²
(Table 1).
A significant decrease was observed in the mean cortisol
hormone levels of the participants before and after the
breathing exercise (p <0.05). When the responses of epinephrine
hormone were examined, it was seen that there was a decrease
in the hormone levels, but this decrease was not found to be
statistically significant (p >0.05) (Table 2).
A positive and considerably weak insignificant relationship was
determined between the mean cortisol and epinephrine of the
participants following the breathing exercise (r=0.039; p >0.05).
Table 1. Results related to the participants’ mean age,
height, body weight, and body mass index
Variables n Min Max SD
Age (year) 15 24.00 35.00 29.06 4.26
Height (cm) 15 159.00 171.00 163.66 3.81
Body weight (kg) 15 47.60 62.50 54.98 4.97
Fat (%) 15 16.70 31.20 24.20 4.23
BMI (kg/m²) 15 17.00 23.50 20.55 1.78
Min, Minimum; Max, Maksimum; SD, Standard deviation; n, Number.
Figure 1. Breathing exercise.

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DISCUSSION
The most important finding of this study conducted to determine
the effects of the breathing exercises on some stress hormones,
is that epinephrine and cortisol hormone levels decreased after
an acute breathing exercise; however, while this change was
significant in cortisol hormone, it was not found in epinephrine
hormone. Moreover, there was a positive and highly weak
insignificant relationship between the stress hormones.
The control mechanisms of the body are the nervous system
and endocrine system. These two systems are responsible for
the regulation of the body’s physiological and psychological
processes. Like the increase in the happiness hormone levels
when feeling happy and stress hormone levels when feeling
stressed and nervous, mood state may also change with the effect
of hormones psychologically. Stress is accepted as a condition in
which emotional and psychological components are no longer
in harmony with the physical components of health. If this
condition is perceived and evaluated by the brain as danger, stress
reaction begins to function. Some subcortical areas are activated
in the brain, and they try to regulate the normal function of
the body. The first activated system is the hypothalamus, and
it immediately begins to secrete hormones. The effects of stress
are not only limited to psychological components; stress also
changes the levels of various hormones.22
Cortisol hormone is a reliable indicator stress.23 In addition,
cortisol is a hormone that could involuntarily control some
of the mental processes including metabolism, immunity,
memory, and emotional evaluation, and is easily affected from
the breathing excercises.24 The second system is the secretion
of epinephrine hormone from the adrenal medulla through
the sympathetic nervous system. Both systems are useful in
managing the temporary stress, protective and supportive in the
tissues.8
Janakiramaiah et al.25 interpreted that the plasma cortisol level
remained stable after the first yoga breathing session applied
to the dysthymic patients, and the breathing experience was
not stressful. It is foreseen that sudarshan kriya yoga, which is
a special series of respiration techniques, may relieve anxiety,
depression, daily stress, post-traumatic stress, and stress-
related medical diseases, and may be a useful, low-risk, and
low-cost supplementary treatment for substance abuse and the
rehabilitation of the criminals (26). Evidence obtained from the
randomized controlled study shows that a seven-day intensive
yoga program with pranayama, (i.e., breathing exercises), reduces
anxiety and depression in patients with a chronic low back
pain.27 Like this study, Kharya et al.28 concluded that controlled
breathing exercises, including the Sudarshan Kriya and Prana-
Yoga, positively changed stress coping with the behavior and
initiated an appropriate balance in the cardiac autonomic tone.
Veerabhadrappa et al.29 detected a significant decrease
in the Beck Depression Inventory score after a two-week
breathing exercise to determine the antidepressant efficiency
and hormonal effects of the yogic breathing technique on
alcohol addicts. As a result of this study, it was stated that this
improvement in the psychological condition may have been
caused by the significant decrease in the cortisol levels. In
another study, it was reported that a breathing exercise of five
minutes and 30 sessions per day could significantly reduce the
anxiety in pregnant women who experienced preterm labor.30
Salyers et al.31 emphasized that a one-day breathing exercise
relieved an emotional exhaustion, and depersonalization caused
by occupational burnout. In a study conducted to determine the
effects of the diaphragmatic respiration on exercise-induced
oxidative stress and the potential role of the cortisol hormone
in this stress condition, it was found that diaphragm breathing
applied after an intensive training increased the antioxidant
defense status, and this situation resulted from the decrease
in the cortisol level.32 Naik et al.22 reported that there was a
significant decrease in the resting heartbeat rate, systolic and
diastolic blood pressure, and perceived stress conditions of
100 male volunteers who performed slow and deep breathing
exercise for 30 minutes 5-times a week for 12 weeks, and it was
effective in the improvement of the cardiovascular parameters.
It is emphasized that a rhythmic and controlled breathing
type, which includes cyclic breathing where medium and short
breath followed by a long breath, may play an important role
in promoting the healthy lifestyle by improving the immune
system, antioxidant condition, hormonal condition, and the
brain function.33 The mechanism through which breathing
exercises are thought to reduce stress is a decrease in the serum
cortisol levels as well as a direct decrease in the sympathetic
Table 2. T-test result of the mean 1st and 2nd measurements of cortisol and epinephrine hormones of the participants
Variable Test n Min Max SD t p-value
Cortisol
(µg/dL)
1 15 5.70 15.91 9.48 2.91 4.609 0.000*
2 15 3.25 13.09 6.28 2.20
Epinephrine
(mg/dL)
1 15 11.06 179.30 115.79 53.43 0.524 0.608
2 15 45.29 175.51 109.55 40.83
*p <0.05; Min, Minimum; Max, Maksimum; SD, Standard deviation; n, Number.

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26
activity which enables the domination of a parasympathetic
tone. Decreased cortisol levels are related with an increased sense
of happiness, decreased anxiety, and an increased threshold for
stress perception.34
When the above-mentioned studies are examined, it is observed
that the studies examining the responses of the breathing
exercises to stress hormones mostly include special yoga breathing
sessions for psychological and therapeutic purposes.15,25,27,28,30 In
the present study, unlike the other studies, an acute effect of
a breathing exercise performed by the healthy individuals on
epinephrine and cortisol hormones was examined. Our study
differs from other studies in this respect.
Limitations of the Study
This research has some limitations; all female participants
included in this research were examined in terms of stress
hormones because of only one breathing exercise; however,
the effects of the age groups, gender, and different breathing
exercises could not be examined. The absence of a control
group is one of the limitations of this study, as there were not
enough participants with the same conditions in the study, and
therefore, it was not possible to compare the breathing exercise
group with a control group. The pre-exercise values of the
experimental group were accepted as the basic values by making
a comparison within the group. In the new studies to be carried
out, experiment and control groups could be formed and the
difference between the groups may be evaluated. Furthermore,
blood samples were taken as a single sample before and after
the exercise at the morning hours. However, since the day and
night rhythms of the hormones differ during the day, not taking
samples at certain intervals may have been affected the results
of the study.
CONCLUSION
Cortisol is secreted in a pulsatile manner. In humans,
cortisol secretion has a circadian rhythm, and the cortisol
concentration reaches its peak level during the morning
hours.35 Later, cortisol gradually declines in the body during the
day until evening. Since our research aim was to determine the
effect of an acute breathing exercise on the stress hormones,
cortisol levels during the day could not be measured. This is
one of the limitations of the research. Therefore, considering
this limitation, the morning hour, which is stated to have a
high cortisol secretion, was preferred to see the effect of the
breathing exercise. The significant decrease in the cortisol
levels after 45 mins of breathing exercise is thought to have
stemmed from breathing exercise. As a matter of fact, cortisol
is a hormone that is easily affected by breathing.24 In other
studies, indicating that breathing exercises reduces the cortisol
levels, there have been references supporting our study
results.25,29,32,34
As a result, it was determined that an acute breathing exercise
decreased stress hormone levels. Considering the long-term
effects of breathing exercise, it could be stated that it has healing
effects in non-pharmacological areas in terms of balancing the
emotions and managing stress.
Main Points
• Breathing is based on an energy flow that is much more
than moving downward/upward, expanding/narrowing of the
chest and abdomen area in the physical body and how this
flow affects our bodies physically, mentally, and spiritually.
As a vital function, respiration is not regulated by the certain
hormones but is affected by a wide variety of hormones.
Breathing techniques are regularly applied for relaxation, stress
management, control of psycho-physiological states and to
improve the organ function.
• The aim of this study is to determine the acute effects of
breathing exercise on stress hormones in young women.
• It could be stated that natural and connected breathing
exercise has a reducing effect on stress hormones, and
accordingly, breathing exercises could be used as a relaxation
technique.
ETHICS
Ethics Committee Approval: For this study, approval was
obtained from Selçuk University Faculty of Sports Sciences
Non-Interventional Clinical Researches Ethics Committee on
20.12.2018 with the decision number of 65.
Informed Consent: All subjects gave their informed consent for
inclusion before they participated in the study.
Peer-review: Externally peer-reviewed.
Authorship Contributions
Concept: D.Ö., S.K., Ş.A; Design: D.Ö., S.K., Ş.A.; Supervision:
D.Ö., S.K.; Fundings: S.K.; Materials: D.Ö.; Data Collection and/or
Processing: D.Ö.; Analysis and/or Interpretation: S.K.; Literature
Search: D.Ö., S.K., Ş.A.; Writing: D.Ö., S.K., Ş.A.; Critical Review: Ş.A.
DISCLOSURES
Financial Disclosure: This study was supported by the Selçuk
University Scientific Research Projects (S.U. BAP, Konya, Turkey)
(project no: 19401116).
Conflict of Interest: The authors declare no conflict of interest.
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