Oka and Lkhagvasuren ﻿
BioPsychoSocial Medicine(2022) 16:14
https://doi.org/10.1186/s13030-022-00243-4

Open Access

RESEARCH

Effects of practicing yoga on alexisomia:
an open‑label trial
Takakazu Oka1,2* and Battuvshin Lkhagvasuren1

Abstract
Background: Alexisomia refers to difficulties in the awareness and expression of somatic feelings. This idea wasproposed by Dr. Yujiro Ikemi as a characteristic observed in patients with psychosomatic diseases and is based on his
observations that patients with psychosomatic diseases have difficulty in the awareness and expression of not only
their emotions, i.e., alexithymia, but also somatic feelings and sensations, i.e., alexisomia. He also proposed that treating alexisomia is important in the treatment of psychosomatic diseases and that yoga might help improve alexisomia. However, no study has investigated if yoga actually affects alexisomia. This open-label pilot study investigatedwhether practicing yoga in a class results in change in patients with alexisomia and alexithymia.
Methods: The Shitsu-taikan-sho Scale (STSS) and the Toronto Alexithymia Scale (TAS-20) were administered to 305
participants, including 64 healthy participants, 111 participants who had subjective symptoms without abnormal
findings, and 130 participants with chronic diseases. Participants were tested before and 3 months after attending
yoga classes.
Results: Yoga practice reduced the STSS and the TAS-20 difficulty in identifying feelings (DIF) subscale scores. Multiple linear regression indicated that a reduction in the TAS-20 DIF subscale scores predicted a decrease in the STSS
score, whereas reductions in the STSS difficulty in identifying bodily feelings (DIB) and the lack of health management
based on bodily feelings (LHM) subscale scores predicted a decrease in the TAS-20 scores.
Conclusion: We found that regular yoga practice improves alexisomia. Yoga-induced improvement of alexisomia
may be mediated, at least in part, by an improvement of DIF in alexithymia. Yoga would be a promising therapeutic
approach to improve alexisomia.
Keywords: Alexisomia, Alexithymia, Yoga, Shitsu-taikan-sho, STSS, TAS-20
Background
Alexisomia refers to difficulties in the awareness andexpression of somatic feelings (for a review, see [1]). This
concept was first proposed by Ikemi Y. as a characteristic
observed in patients with psychosomatic diseases [2]. In
1973, P.E. Sifneos published the concept of alexithymia(difficulty in identifying and describing one’s emotions)*Correspondence: okatakakazu@gmail.com
1
Department of Psychosomatic Medicine, International University of Healthand Welfare Narita Hospital, 852 Hatakeda, Narita, Chiba 286‑8520, Japan
Full list of author information is available at the end of the article

as a characteristic of patients with psychosomatic diseases [3]. Soon after, Ikemi noted, “In many cases ofalexithymia, where there is an observed difficulty in theawareness and expression of feelings, there also seems to
be a difficulty in the awareness and expression of bodily
feelings”. He coined the term alexisomia to designate thecondition wherein people have difficulty in expressing
how their bodies feel [4].
Ikemi observed characteristics of both alexithymia andalexisomia in patients with psychosomatic diseases, but
he placed more importance on alexisomia. The conceptof alexisomia emphasizes bodily (interoceptive/proprioceptive) awareness, whereas alexithymia emphasizes© The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which
permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to theoriginal author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images orother third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line
to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory
regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of thislicence, visit http://​creat​iveco​mmons.​org/​licen​ses/​by/4.​0/. The Creative Commons Public Domain Dedication waiver (http://​creat​iveco​
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Oka and Lkhagvasuren ﻿BioPsychoSocial Medicine(2022) 16:14

emotions in general. Ikemi hypothesized that body-oriented, somatopsychic approaches such as yoga, whichalter proprioceptive afferent discharge, may be effective
for alexithymic conditions and their related psychosomatic diseases [5]. He postulated the importance ofintegrating somatopsychic approaches and psychosomatic approaches, such as psychotherapy, in treating
psychosomatic diseases [4, 5]. However, other than somecase reports, no experimental studies have investigatedwhether body-oriented intervention actually improves
the alexisomia of patients with psychosomatic diseases[6].
Yoga is a mind/body exercise that includes asana(poses), pranayama (breathing exercises), and meditation through which practitioners focus their attention on
bodily feelings (slow movements, breathing, or relaxed/
stretched muscle tension) and associated psychologicalfeelings (calmness and peacefulness) [7]. We hypothesized that this mind/body approach of yoga ameliorates
alexisomia. The STSS, a self-rating questionnaire, is ascreening test that evaluates alexisomia without the needfor a professional diagnosis [8, 9]. Therefore, to test our
hypothesis in a pilot study, we investigated changes in
the STSS scores of adult participants who began practicing yoga in yoga studios. Considering the close relation
between alexisomia and alexithymia, we also investigatedwhether yoga practice affected alexithymia and whether
improvement in alexisomia was associated with alexithymia and vice versa.

Methods
Study design

This study enrolled 390 adults who had not previously
practiced yoga and began practicing it for the first time inyoga studios. They attended weekly yoga classes for threemonths. Participants completed two self-rating questionnaires, the STSS and the TAS-20, before the beginning of
the first class and again after 3 months of attendance.
Participants were divided into three groups: healthy
control participants (HC group; no subjective symptoms), participants with poor health (PH group; several subjective symptoms but having normal findings inphysical examinations and medical tests), and participants with chronic disease (CD group; diagnosed withchronic diseases and on medication). Participants in the
PH group did not receive any medical treatment, whereas
those in the CD group received treatment for hypertension, low back pain, autonomic dysfunction, depression,and climacteric disorder, among others.
Yoga classes

Yoga classes were held weekly, with a duration of 60 to
90 min. Most participants practiced yoga in class once

Page 2 of 8

a week and some also practiced at home. The classes
included 5 to 20 participants and were taught by certified
yoga therapists of the Japan Yoga Therapy Society according to the society’s guidelines. Each class had a similar
structure, i.e., the yoga class included asanas (yoga poses),pranayamas (breathing exercises), meditation, isometricyoga poses (poses practiced with low impact isometricload and with long breathing [10, 11] that induce postisometric relaxation [12]), and savasana (corpse pose).
While practicing yoga, participants were encouraged tomove slowly with breathing and to observe bodily sensations and feelings, which changed from tension to relaxation, comfort, calmness or peacefulness.
Questionnaires

The STSS is a 23-item self-report questionnaire thatassesses alexisomia and has three subscales: 1) difficultyin identifying bodily feelings (DIB), 2) overadaptation(OA), and 3) lack of health management based on bodily feelings (LHM). The STSS was developed in Japan andshows strong reliability and validity for assessing alexisomia [8]. Each item was evaluated on a 5-point Likert
scale, ranging from 1 “definitely false” to 5 “definitely
true”. The DIB subscale evaluates the failure to notice
bodily sensations that act as warning signals during
adaptation to external environments and that are necessary to maintain one’s homeostasis, as well as the failure
to notice relaxed feelings that are necessary to prevent
allostatic load. The OA subscale assesses the tendency
to ignore warning signals from the body that result fromprioritizing social demands and adapting to external
environments despite feelings of fatigue, sleepiness, or adesire to rest. The LHM subscale evaluates habits related
to maintaining daily health and assessing bodily sensations coming from physical conditions of the relaxation
response [1, 8].
The TAS-20 is a 20-item self-report questionnaire withthree subscales that evaluates alexithymia: 1) difficulty in
identifying feelings (DIF), 2) difficulty in describing feelings (DDF), and 3) externally-oriented thinking (EOT)[13]. The Japanese version of the TAS-20 has been shown
to be reliable and valid for use with general and clinicalpopulations [14].
The STSS total and subscale scores have strong correlations with the TAS-20 total and subscale scores,
especially the STSS DIB subscale and the TAS-20 DIF
subscale scores [8].
Statistical analysis

Results are presented as mean ± standard deviation (SD).
The non-parametric paired samples Wilcoxon signedrank test was used to assess the effects of yoga on alexisomia and alexithymia in comparison of the STSS andOka and Lkhagvasuren ﻿BioPsychoSocial Medicine(2022) 16:14

TAS-20 scores before and after 3 months of regularyoga practice. Two-way repeated ANOVA was used to
examine differences in changes in the STSS and TAS-20
scores before and after the yoga practice, considering
time effects and interactions between the groups. Correlations between continuous variables were assessed by
Pearson’s correlation. Multiple linear regression with theenter method was conducted to examine whether age,sex, and changes in the TAS-20 subscale scores (independent variables) predicted changes in the STSS scores(dependent variables). To minimize type 1 errors acrossquestionnaire scores, p values were adjusted for multiple
comparisons by the use of an adaptive linear step-up procedure that controls the false discovery rate [15]. Effectsizes for significant differences in the values were calculated using the Wilcoxon r, Cramer’s V, and eta squared(η2) with a 95% confidence interval (CI) as appropriate.
Statistical significance was set at p < 0.05, and all tests
were two-tailed. Data were analyzed using SPSS v.21.0.

Page 3 of 8

In Table 2, further analysis using a two-way repeated
ANOVA confirmed that the yoga practice reduced the
STSS total and subscale scores during the period of yoga
practice (within-subject effects: p < 0.001, p = 0.001,
p = 0.016, and p < 0.001, respectively). The change in DIB
over time (ΔDIB) was significantly different between thegroups (p = 0.023, F = 3.804), and there was no significant interaction effect. These results suggest that yoga
improves alexisomia. Furthermore, Tukey’s post-hoc test
indicated that the difference between the estimated marginal mean of the H group (21.3 ± 0.7) and that of the CDgroup (23.4 ± 0.5) was significant (p = 0.037) but there
was no difference between the PH group (21.9 ± 0.5) andthe H and CD groups. These results suggest that the Hgroup benefited in particular from yoga practice for DIB(Fig. 1a).
TAS‑20Three hundred ninety adults who had begun practicing
yoga for the first time were enrolled. Among these participants, 57 discontinued the class within three months
and 28 were excluded from the analysis due to missing
values, leaving the data of 305 participants available forthe final analysis. The participants were aged from 21 to
92 years: 64 in the H group, 111 in the PH group, and 130
in the CD group (Table 1). The male/female ratio was notdifferent among the groups. However, there was a significant difference in age among the three groups (p < 0.001,
F = 16.35).
The number of dropouts in each group was 13 (15.5%)in the H group, 23 (16.3%) in the PH group, and 21(12.7%) in the CD group. Rates of dropouts were not different among the groups (p = 0.718, χ2 = 0.663).

In contrast, there was no difference between the TAS-20
total and subscale scores before and after yoga practicein any group or for all participants, by the non-parametric paired test (Table 1). However, two-way repeated
ANOVA revealed that the DIF score decreased in allparticipants (within-subject effect: p = 0.026). Furthermore, the change in DIF across time (ΔDIF) was different between the groups (p = 0.045, ­F5 = 3.12), and there
was no interaction effect (Table 2). These findings suggest that yoga improves critical components of alexithymia, i.e., difficulty in identifying feelings. Furthermore,
Tukey’s post-hoc test suggests that the estimated marginal mean of the H group (15.0 ± 0.6) differed significantly from those of the PH (16.6 ± 0.4) and CD groups(16.6 ± 0.4) (p = 0.049 and p = 0.038, respectively), butthere was no difference between the PH and CD groups(p = 0.999). We also found that the mean DIF before
and after yoga differed between the groups in one-way
ANOVA (p = 0.022 and p = 0.027, respectively).

STSS

Factors to STSS

The mean STSS total score in the study population was
decreased from 59.2 points to 56.2 points through yoga
practice. Table 1 shows the Wilcoxon signed-rank test
results indicating that the STSS total and subscale scores(DIB, OA, and LHM) decreased during the period of
yoga practice among all participants (p < 0.001, p = 0.001,
p = 0.003, and p < 0.001, respectively). In all groups (H,PH, and CD), the STSS total score was reduced after yoga
practice (p = 0.032, p < 0.001, and p = 0.001, respectively).
The PH group showed improvement in all subscales,
whereas the H and CD groups improved on the DIB and
LHM subscales, respectively. The STSS scores of the PH
and CD groups were higher than those of the H group(Table 1).

Table 3 shows the results of multiple linear regression
with the enter method indicating that the ΔDIF score of
TAS-20 was a predictive factor. It accounted for 14% of
the variance of the ΔSTSS total score ­(F5 = 9.9, p < 0.001).
This model showed that there was no multicollinearity
detected between the tested variables (1 < VIF < 2.5; tolerance < 10); no outliers (Cook’s distance < 1; standard
residuals <  ± 3.3); and the independence assumption was
satisfied (1.5 < Durbin-Watson < 2.5). The distribution of
the residuals satisfied normality assumptions. The variance of the model was constant and homoscedasticity
was not violated. Similarly, the ΔDIF subscale score of
the TAS-20 predicted the ΔSTSS subscale scores, including the ΔDIB, ΔOA and ΔLHM scores (Table 3). No

Results
Demographics

21.9 ± 5.9

16.7 ± 5.6

17.8 ± 4.8

49.9 ± 8.2

15.9 ± 4.8

14.1 ± 3.2

19.8 ± 3.7

Post

Post

Post

Post

Post

Post

Pre

Pre

Pre

Pre

Pre

Pre

19.6 ± 4.0

14.4 ± 3.4

16.5 ± 5.2

50.5 ± 9.5

18.9 ± 4.5

17.4 ± 5.2

22.9 ± 5.9

Post

Pre

0.215

0.230

0.026

0.596

< 0.001

0.003

0.001

< 0.001< 0.001

0.064

0.612

0.612

0.422

0.810

< 0.001

0.006

0.002

< 0.001

0.06

0.04

0.05

0.03

0.27

0.17

0.13

0.26

0.10

0.13

20.0 ± 3.4

20.2 ± 3.7

14.0 ± 3.2

13.9 ± 3.0

14.8 ± 4.1

15.2 ± 4.0

48.8 ± 7.9

49.3 ± 8.1

17.9 ± 6.9

18.0 ± 4.1

16.8 ± 4.6

17.1 ± 4.6

20.7 ± 5.7

22.0 ± 6.2

54.8 ± 10.2

57.2 ± 10.9

53.6 ± 14.4

64
11 / 53

0.828

0.848

0.421

0.700

0.159

0.661

0.027

0.032

UPV

0.848

0.848

0.744

0.810

0.181

0.661

0.042

0.043

FPV

0.01

0.01

0.05

0.02

0.08

0.03

0.28

0.12

ES

19.6 ± 4.2

19.6 ± 4.7

14.0 ± 3.3

14.4 ± 3.0

16.4 ± 5.2

16.7 ± 5.0

50.1 ± 8.2

50.2 ± 10.0

18.1 ± 4.3

19.3 ± 4.5

16.3 ± 5.1

17.7 ± 4.8

21.5 ± 6.1

22.4 ± 5.9

55.9 ± 11.2

59.4 ± 10.8

48.0 ± 14.6

111
7 / 104

Values

PH

0.080

0.465

0.325

0.708

< 0.001

0.001

0.033

< 0.001

UPV

0.427

0.744

0.743

0.810

< 0.001

0.003

0.043

< 0.001

FPV

0.10

0.04

0.06

0.02

0.21

0.18

0.20

0.24

ES

19.9 ± 3.4

19.7 ± 3.5

14.3 ± 3.2

14.7 ± 3.8

16.1 ± 4.7

17.0 ± 5.7

50.4 ± 8.2

51.4 ± 9.7

17.4 ± 3.9

19.1 ± 4.8

17.0 ± 6.1

17.2 ± 5.8

23.0 ± 5.8

23.7 ± 5.7

57.2 ± 11.3

60.1 ± 11.6

58.6 ± 14.1

130
12 / 118

Values

CD

0.678

0.217

0.057

0.382

< 0.001

0.214

0.095

0.001

UPV

0.810

0.612

0.427

0.744

< 0.001

0.228

0.117

0.003

FPV

0.02

0.07

0.11

0.05

0.22

0.07

0.15

0.19

ES

CD Chronic disease, DDF Difficulty in describing feelings, DIB Difficulty in identifying bodily feelings, DIF Difficulty in identifying feelings, EOT Externally-oriented thinking, ES Effect size between Pre and Post (Wilcoxon r/
Cramer’s V/ Eta squared η.2), f Female, FPV False discovery rate–adjusted p values for multiple comparisons (Pre vs Post, Wilcoxon signed rank test), H Healthy, LHM Lack of health management based on bodily feelings, mMale, OA Overadaptation, PH Poor health, Post After practicing yoga for 3 months, Pre Before starting to practice yoga, STSS The Shitsu-taikan-sho Scale, TAS-20 The 20-item Toronto Alexithymia Scale, UPV Unadjusted pvalues

EOT

DDF

DIF

TAS-20, Total

LHM

OA

DIB

56.2 ± 11.1

Post

59.2 ± 11.2

53.7 ± 15.0

Age, years

Pre

305
30 / 275

STSS, Total

ES

ValuesFPV

Values

UPV

H

Total

NumberSex, m / fGroup

Table 1 Effects of yoga on the STSS and TAS-20 scoresOka and Lkhagvasuren ﻿BioPsychoSocial Medicine(2022) 16:14
Page 4 of 8

Oka and Lkhagvasuren ﻿BioPsychoSocial Medicine(2022) 16:14

Page 5 of 8

Table 2 Effects of yoga practice on the STSS and TAS-20 of the H, PH, and CD groups assessed by two-way repeated ANOVA
Scale
STSS

TAS-20Overall p value

F value

Within-subject

Inter-action

ES (η2)

Power

Total

0.229

1.480

< 0.001

0.744

0.010

0.32

DIB

0.023

3.804

0.001

0.776

0.025

0.69

OA

0.973

0.027

0.016

0.137

0.001

0.05

LHM

0.468

0.761

< 0.001

0.094

0.005

0.18

Total

0.298

1.214

0.246

0.589

0.008

0.26

DIF

0.045

3.125

0.026

0.528

0.020

0.60

DDF

0.367

1.006

0.276

0.595

0.007

0.22

EOT

0.320

1.143

0.389

0.842

0.008

0.25

DDF Difficulty in describing feelings, DIB Difficulty in identifying bodily feelings, DIF Difficulty in identifying feelings, EOT Externally-oriented thinking, ES Effect size
between Pre and Post (Eta squared η2), LHM Lack of health management based on bodily feelings, OA Overadaptation, STSS The Shitsu-taikan-sho Scale, TAS-20 The
20-item Toronto Alexithymia Scale

Fig. 1 Effect of yoga on the STSS, DIB subscale score (a) and the TAS-20, DIF score (b). a: Changes in the estimated marginal means of DIB before
and after yoga practice; b: Changes in the estimated marginal means of DIF before and after yoga practice; CD: chronic disease; H: healthy; PH: poor
health; Post: after practicing yoga for 3 months; Pre: before starting to practice yoga

other subscale scores of TAS-20 were associated with the
ΔSTSS scores. These results suggest that a reduced difficulty in identifying feelings contributed to an improvement in alexisomia. Furthermore, all ΔSTSS total andsubscale scores were correlated with the ΔDIF subscalescore before versus after the yoga intervention (Table 3).
This indicates that alexisomia and its subscales are correlated with alexithymia, especially for the subscale of difficulty in identifying feelings. Moreover, we analyzed thecontribution of the TAS-20 subscale scores before andafter yoga practice to the changes in the STSS total andsubscale scores (Appendix 1). The results suggest that
only DIF before yoga predicts the ΔSTSS total and ΔDIB,
confirming the above-mentioned findings.

Factors to TAS‑20

Table 4 shows the results of multiple linear regression
with the enter method. They indicate that the ΔDIB
and ΔLHM scores of STSS were predictive factors, andthey accounted for 10% of the variance of the ΔTAS20 total score (p < 0.001, ­F5 = 6.64). This model showed
there was no multicollinearity between the tested variables (1 < VIF < 2.5; tolerance < 10), there were no outliers(Cook’s distance < 1; standard residuals <  ± 3.3), and the
independence assumption was satisfied (1.5 < DurbinWatson < 2.5). The distribution of the residuals satisfied
normality assumptions. The variance of the model wasconstant and homoscedasticity was not violated. Similarly, the ΔDIB and ΔLHM scores of the ΔSTSS predictedOka and Lkhagvasuren ﻿BioPsychoSocial Medicine(2022) 16:14

Page 6 of 8

Table 3 Multiple linear regression for the ΔSTSS scores of all
subjects. N = 305 (independent variables: age, sex, ΔDIF, ΔDDF,
and ΔEOT)

Table 4 Multiple linear regression for the ΔTAS-20 scores of all
subjects. N=305 (independent variables: age, sex, ΔDIB, ΔOA,
and ΔLHM)

Independent
variables

Independent
variables

Mean ± SD

Dependent variables (ΔSTSS)
ΔTotal

ΔDIB

ΔOA

ΔLHM

Dependent variables (ΔTAS-20)
ΔTotal

ΔDIF

ΔDDF

ΔEOT

Model summary (r2)0.142

3.03 ± 9.09 0.93 ± 4.83 0.69 ± 4.57 1.16 ± 4.62
0.121

0.043

0.036

Mean ± SD

Model summary ­(r2)

0.100

0.139

0.049

0.018

F value

9.860

8.235

2.662

2.241

F value

6.640

9.639

3.111

1.094

Durbin-Watson

1.923

2.097

1.850

1.946

Durbin-Watson

2.092

2.096

2.087

2.033

Cook’s distance

0.107

0.076

0.90

0.128

Cook’s distance

0.060

0.078

0.090

0.136

p value< 0.001< 0.001

0.023

0.05

p value< 0.001< 0.001

0.009

0.364

Constant

5.521

1.504

1.600

1.734

Constant-1.9910.261-0.838-1.550Age(mean ± SD: 53.69 ± 15.05; VIF: 1.020)

Age(mean ± SD: 53.69 ± 15.05; VIF: 1.020)

r

0.58 ± 7.72 0.61 ± 4.23 0.26 ± 3.14 -0.23 ± 3.52

-0.101

0.003-0.083-0.071r

0.024-0.033

0.007

0.090

B

-0.0550.004-0.023-0.022B-0.055-0.005-0.0230.022

p value

0.093

0.820

0.195

0.219

p value

0.093

0.724

0.195

0.101

Sex

(male/female: 30/275; VIF: 1.010)

Sex(male/female: 30/275; VIF: 1.010)

r

0.011

-0.032

0.014

0.023

r

0.009

0.004

0.031

-0.006B-0.002-0.549

0.085

0.270

B

0.449

0.113

0.085

0.014

p value

0.999

0.535

0.922

0.760

p value

0.753

0.883

0.922

0.984

ΔDIF

(mean ± SD: 0.61 ± 4.23; VIF: 1.379)

ΔDIB(mean ± SD: 0.93 ± 4.83; VIF: 1.158)

0.364***

0.342***

0.189**

0.161**

r

B

0.731

0.368

0.198

0.171

p value< 0.001< 0.001

0.006

0.019

ΔDDF

(mean ± SD: 0.26 ± 3.14; VIF: 1.361)

r

0.285***

0.342***

0.211**

0.027

B

0.407

0.270

0.128

0.017

p value< 0.001< 0.001

0.001

0.710

ΔOA

(mean ± SD: 0.69 ± 4.57; VIF: 1.166)

r

0.213***

0.211***

0.105

0.070

r

B

0.110

0.077

0.021

-0.028p value

0.545

0.428

0.827

0.773

ΔEOT

(mean ± SD: -0.23 ± 3.52; VIF: 1.035)

r

0.157**

0.189***

0.105-0.003

B

0.094

0.059

0.021

-0.010p value

0.350

0.272

0.622

0.838

ΔLHM

(mean ± SD: 1.16 ± 4.62; VIF: 1.017)
0.146**

0.161**

0.070

0.091

B

0.019

0.116

0.034

0.074

0.193

p value

0.030

0.020

0.379

0.095

0. ­146*ΔSTSS total r

0. ­311***0. ­364***0. ­213**

0. 058

0.058

0.027

-0.003

0.091

r

B

0.025

-0.40

-0.0340.099

p value

0.859

0.595

0.652

ΔTAS-20 total r

0. ­311***0. ­285***

0. ­157**

Δ: differences between scores before and after 3 months of yoga practice;*p < 0.05; **p < 0.01; ***p < 0.001 for correlation coefficients (r) with the Pearson’s
correlation, DDF Difficulty in describing feelings, DIB Difficulty in identifying
bodily feelings, DIF Difficulty in identifying feelings, EOT Externally-oriented
thinking, LHM Lack of health management based on bodily feelings, OA
Overadaptation, p value Multiple linear regression with the enter method,
SD Standard deviation, STSS The Shitsu-taikan-sho Scale, TAS-20 The 20-item
Toronto Alexithymia Scale, VIF Variance inflation factor

Δ: differences between scores before and after 3 months of yoga practice;*p < 0.05; **p < 0.01; ***p < 0.001 for correlation coefficients (r) with the Pearson’s
correlation, DDF Difficulty in describing feelings, DIB Difficulty in identifying
bodily feelings, DIF Difficulty in identifying feelings, EOT Externally-oriented
thinking, LHM Lack of health management based on bodily feelings, OA
Overadaptation, p value Multiple linear regression with the enter method,
SD Standard deviation, STSS The Shitsu-taikan-sho Scale, TAS-20 The 20-item
Toronto Alexithymia Scale, VIF Variance inflation factor

the ΔDIF subscale score of TAS-20 (Table 4). Moreover,
ΔDIB alone predicted the ΔDDF subscale score of TAS20. In contrast, ΔOA of STSS was not associated with any
ΔTAS-20 score, although it correlated with ΔDIF. ΔEOT
had no correlation with any ΔSTSS score (Table 4). We
also analyzed the contribution of the STSS subscalescores before and after yoga practice to the changes in
the TAS-20 total and subscale scores (Appendix 2). The
results suggest that LHM before yoga predicts all of the
ΔTAS-20 scores, whereas DIB before yoga predicts only

ΔDIF. These results suggest that reduced alexisomia contributed to an improvement in the alexithymia components, including difficulty in identifying and describing
feelings.

Discussion
The present study is the first to investigate the effect ofyoga on alexisomia. We demonstrated that practicing
yoga for 3 months decreased the STSS total scores of allof our study groups. Because the STSS scores in the PH

Oka and Lkhagvasuren ﻿BioPsychoSocial Medicine(2022) 16:14

and CD groups were higher than that of the H group,
which was identical to that of healthy university students(56 ± 10) in our previous study [8], the findings suggestthat yoga can reduce the degree of alexisomia of thosewith poor health or a chronic disease to a healthy level.
The mechanisms underlying the improvement of alexisomia are still unclear. One possibility may related to
how yoga is instructed. During class, instructors encourage participants to be mindful of inner bodily sensations,such as breathing and muscle tension/relaxation. It isreasonable to hypothesize that these practices enhanceinteroceptive awareness, which leads to improved alexisomia, especially the DIB component. Studies on whether
yoga can improve interoceptive awareness are limited[16, 17], and future studies are necessary to investigate
this hypothesis.
Yoga also improved the OA and LHM subscale scores.
These changes may also be linked to the way yoga is practiced. The OA subscale assesses the tendency to ignore
warning signals from the body that result from prioritizing social demands, despite fatigue or the desire forrest. The LHM subscale assesses habits related to daily
health maintenance. After practicing many poses, participants observe and “taste” inner feelings, which areusually relaxed, comfortable, calm, and peaceful ones,
during meditation and savasana. These yoga practices
may gradually shift participants’ mindset, coping, andlifestyle from meeting social demands and ignoring physical needs to following the “voice of the body”.
In addition to the STSS scores, yoga also decreased the
DIF subscale score of the TAS-20 according to the resultsof two-way repeated ANOVA. Several studies have investigated yoga’s effects on alexithymia [18, 19], but theirfindings are controversial. One study showed that yoga
reduced the TAS-20 score of patients with mild to moderate depression and anxiety [19], whereas another study
demonstrated that yoga did not change the TAS-20 scoreof those with myalgic encephalomyelitis/chronic fatigue
syndrome [18]. These differences may be due to different
study populations or degrees of alexithymia. Consideringthat the TAS-20 score of a healthy Japanese sample was
48 ± 9 [14], participants in this study exhibited a lower
level of alexithymia compared to healthy people. Thismight explain why yoga had limited effects on the TAS20 total and subscale scores in this study. To determine if
yoga can affect alexithymia, future studies of people withalexithymia will be necessary.
In this study, we found that the ΔSTSS scores werepositively correlated with the ΔTAS-20 scores, particularly with ΔDIF. These results support our previous study results in which we evaluated the external
validity of STSS using TAS-20 and found correlations
between the measures [8]. The present study used

Page 7 of 8

multiple linear regression to further analyze theseassociations and found that 14% of the variance of theΔSTSS total score was predicted by ΔDIF. Furthermore, ΔDIF predicted changes in all STSS subscales,i.e., DIB, OA, and LHM. In turn, regression analysis
for alexithymia suggests that the improvement of alexithymia (DIF and DDF) of TAS-20 due to yoga canpartially explain the improvement of alexisomia (DIBand LHM). These results indicate that STSS is distinct
from TAS-20 structurally, but also that it is partiallyconvergent. During yoga, participants are directed tofocus on inner feelings, and this focus is associatedwith attention to changes in proprioception/interoception and enhanced emotional awareness. These
practices may help improve alexithymia, especially thedifficulty in identifying feelings component and may
contribute to improving alexisomia.
There are several limitations in this study. First, thedata collected were self-reported measures. It is controversial whether self-administered questionnaires suchas the TAS-20 and STSS can be used as screening tools
for alexithymia or alexisomia [1, 14, 20–22]. Therefore, although this study suggested that yoga improved
alexisomia, this finding needs to be confirmed throughmedical interviews by experts in psychosomatic medicine who are familiar with this concept. Second, thisis an open-label trial. Therefore, to determine whether
yoga definitely provides these changes, it will be necessary to compare the changes in these values with a control group in a randomized, controlled trial. Because
participants of the CD group were on medication, there
remains a possibility that their medical treatment had
some effect on the STSS scores. Third, because wemeasured only STSS and TAS-20 in this study, it isdifficult to explain how yoga affected alexisomia andalexithymia differently. To address this question anddiscriminate the effects of yoga on the specific characteristics of alexisomia and alexithymia, future studies are needed that include more general physical andmental health questionnaires. Fourth, because yoga has
many styles and yoga studios have independent programming, generalizing our conclusions to all types ofyoga is difficult. Fifth, our participants attended yoga
classes of their own volition, meaning they were motivated. Whether yoga would have the same effects on
those without a prior interest in yoga is unclear.
Despite these limitations, we believe that this is the firststudy to show that yoga can reduce STSS scores.

Conclusion
This study suggests that yoga is promising for improving
the alexisomia of adults.

Oka and Lkhagvasuren ﻿BioPsychoSocial Medicine(2022) 16:14

Abbreviations
STSS: The Shitsu-taikan-sho Scale; TAS-20: Toronto Alexithymia Scale-20; DIF:
Difficulty in identifying feelings; HC: Healthy control; PH: Participants with poor
health; CD: Participants with chronic disease; DIB: Difficulty in identifying bodily feelings; OA: Overadaptation; LHM: Lack of health management based on
bodily feelings; DDF: Difficulty in describing feelings; EOT: Externally-oriented
thinking.

Page 8 of 8

3.
4.
5.
6.

Supplementary Information
The online version contains supplementary material available at https://​doi.​
org/​10.​1186/​s13030-​022-​00243-4.

7.

Additional file 1.
Additional file 2.
Acknowledgements
The authors would like to thank Dr. Keishin Kimura, a leader of the Japan Yoga
Therapy Society, for making this study possible, and Dr. Kazuko Konno for
precise data analyses. The author is grateful to Ayako Inoue and Miyo Tanji fordata collection and organization. The author is also grateful to all of the yoga
therapists and attendees of the yoga classes who took the time to participate
in this study.
Authors’ contributions
TO designed the study and collected the data. TO and BL analyzed thedata and wrote the manuscript. Both authors read and approved the final
manuscript.
Funding
This study was supported in part by a grant from the Japan Agency for Medical Research and Development (Integrative Medicine, 17lk0310034h0001 to
Takakazu Oka).

8.
9.

10.

11.

12.
13
14.

Availability of data and materials
Data sharing is not applicable.
15.

Declarations
Ethics approval and consent to participate
The study was approved by the ethics committee of Kyushu University(approval number 28–261). All procedures involving human participants werein accordance with the ethical standards outlined in the 1964 World Medical
Association Declaration of Helsinki and its later amendments or comparable
ethical standards.

16.
17.

18.

Consent for publication
Written informed consent was obtained from each study participant.
Competing interests
The authors declare that they have no conflict of interest.
Author details
1
Department of Psychosomatic Medicine, International University of Healthand Welfare Narita Hospital, 852 Hatakeda, Narita, Chiba 286‑8520, Japan.
2
Department of Psychosomatic Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Received: 30 September 2021 Accepted: 19 May 2022

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