Glycative Stress Research
Online edition : ISSN 2188-3610
Print edition : ISSN 2188-3602
Received : March 16, 2022
Accepted : May 12, 2022
Published online : June 30, 2022
doi:10.24659/gsr.9.2_73

Original article

Physical and mental effects of 12 weeks of hot yoga:
A controlled open-label study
Yoshikazu Yonei 1), Takahiko Sumi 2), Eri Ito 2), Mio Yamagata 2),
Doony Nishimoto 2), Takumi Okada 2)
1) Anti-Aging Medical Research Center and Glycative Stress Research Center,
Faculty of Life and Medical Sciences, Doshisha University, Kyoto, Japan
2) LAVA International, Inc. Tokyo, Japan.

Abstract

The effects of a 60-minute hot yoga program twice a week for 12 weeks in healthy women who were aware of their lack of
exercise were examined and compared with a control group. The analysis subjects were divided into two groups: a control
group (19 subjects, age 43.6 ± 10.3 years, BMI 26.4 ± 0.8) and a hot yoga group (34 subjects, age 44.1 ± 9.5 years, BMI
25.7 ± 0.4), and the hot yoga practitioners were further divided into a wood stone floor group and a regular floor group (17subjects each). Measurements after 12 weeks showed improvement in skin condition (water content, wrinkles, and texture),
improvement in mental stress according to the SF-8 questionnaire, mild improvement in weight, body shape, and flexibility,
decrease in HbA1c, and increase in expression of sirtuin gene SIRT6. No adverse events were noted. A comparison of regularand woodstone floors showed a greater improvement in SF-8 body score when using woodstone floors, and blood tests
showed an avoidable decrease in RBC and Hb, a significant increase in total protein, and a mild increase in CPK, which wasconsidered an advantage of the woodstone floors. In the present study, a 12-week hot yoga program conducted with potentiallyinactive women showed a wide variety of effects and increased SIRT6 expression as a factor involved in the mechanism ofaction. The results suggest that hot yoga, a combination of thermotherapy and yoga, is a safe health promotion method that
increases sirtuin activity and enhances the efficiency of health promotion effects both mentally and physically.

KEY WORDS: hot yoga, yoga, heat therapy, sirtuin, heat shock protein (HSP), SIRT1, SIRT6Introduction

Yoga is an ancient Indian practice that trains the bodyand mind. Through a combination of breathing exercises,
postures known as yoga postures, and meditation, the goal isto relieve tension in the body and mind and to achieve mental
stability and ease. Yoga is usually practiced under natural
conditions without temperature or humidity control (roomtemperature yoga). In Japan, the room temperature is around
28 °C, so the amount of sweating is not so great. Considering
the Indian climate, it is expected that the practice developedin a much hotter and more humid environment and that theamount of sweating would have been higher.

Hot yoga, in contrast, takes place in an environment
with a room temperature of 38- 40 °C and humidity of 5565 %. In a hot and humid environment, the same movements
are physically demanding and can lead to dehydration if
proper hydration is not maintained. However, the advantage
is that even slow movements are suitable for beginners who
are not good at exercising, as they can exert a moderate
physical load and work up a pleasant sweat.
Thermal therapies such as “onsen” therapy and “ganban(bedrock)” baths are popular in Japan. These are known
for their relaxing effects and reduction of mental andphysical stress. Warming the body, i.e., increasing deep bodyContact Address: Professor Yoshikazu Yonei, MD, PhD
Anti-Aging Medical Research Center,
Graduate School of Life and Medical Sciences, Doshisha University
1- 3, Tatara Miyakodani, Kyotanabe, Kyoto, 610- 0394 Japan
TEL & FAX: + 81-774 - 65 - 6394 e-mail: yyonei@mail.doshisha.ac.jp
Co-authors: Sumi T, monitor@yoga-lava.com;
Ito E, e-ito@lava-intl.co.jp; Yamagata M, mio.yamagata@lava-intl.co. jp;
Nishimoto D, doony.nishimoto@lava-intl.co.jp; Okada T, takumi.okada@lava-intl.co.jp_ 73 _

Glycative Stress Research 2022; 9 (2) : 73-92(c) Society for Glycative Stress ResearchPhysical and Mental Effects of Hot Yoga: A Controlled Open-label Study

temperature, relaxes blood vessel walls, dilates blood vessels,
and improves blood flow. Genes and proteins (i.e., heatshock proteins) induced by elevated body temperature havealso been reported.
Hot yoga is a treatment in which heat therapy is added
to room-temperature yoga, however, not enough information
is available on the effects of hot yoga on the body. Therefore,
we conducted an open study on healthy female subjects to
examine the effects of participation in a hot yoga program
twice a week for 12 weeks on the body in an uncontrolled
open study 1). The results showed that the expression of
the sirtuin gene SIRT6 (silent information regulator-6)
increased, reactive oxygen species (ROS) decreased, and skinconditions (water content, elasticity, and texture) improved.
In this controlled open study, we examined the effects of a
hot yoga program on skin condition, oxidative stress, andsirtuin gene expression, and compared the differences when
the program was administered on a regular floor and a woodstone floor.

MethodSubjects

The subjects were 91 healthy women between theages of 20 and 59 years old, who were aware of their lackof exercise and who were able to take hot yoga lessons of
60 minutes per session at least twice a week for 12 weeks
without fail. From among the applicants, 60 participants
who met the selection criteria and did not meet the exclusion
criteria were selected according to the judgment of the study
investigator.
The selection criteria are as follows:
1) Japanese women between the ages of 20 and 59.
2) Those aware of their lack of exercise.
3) Must be able to attend at least two hot yoga classes a
week for 12 weeks, 60 minutes per class.
4) Those who have received a full explanation of the
purpose and content of the study, understand it well,
volunteer to participate, and agree to participate in
the study in writing.
Exclusion criteria are listed below;
1) Those who are currently in hospital or being treatedwith drugs or herbal remedies for any disease.
2) Those on a diet and exercise regimen under medical
supervision.
3) Current or previous history of serious illness.
4) Women around menopause who are experiencing
significant changes in their physical condition.
5) Persons who may show skin allergic symptoms, i.e.,
atopic dermatitis.
6) History of or current drug or alcohol dependence.
7 ) Those who have started taking medicines, healthy
food, supplements that affect the study within thelast month or will start during the study period.
8) Pregnant, lactating, or planning to become pregnant
or lactating.
9) Currently exercising at least three times/week for atleast one hour.

10) Have never attended hot yoga on a regular basis(except for trial only).
11) Work for a yoga studio, gym, or other fitness-relatedcompany, or have a family member or close relative
living with them who works for a yoga studio, gym,or other fitness-related company.
12) Who have participated or are currently participating
in another clinical trial within one month prior to
obtaining consent, or will participate during thestudy period.
13) Persons who have been determined by the investigatorto be ineligible for participation in this study.

Fig. 1 shows the number of subjects tested.

Study design
The study was a controlled, open-label study.
The allocation manager, who was not involved in the
study, first divided the 60 subjects into the following two
groups, taking their age and weight into consideration toprevent bias;
A control group: 20 subjects who did not practice hot
yoga and recorded their daily life.
Hot yoga group: 40 subjects who practice hot yoga at
least twice a week.
Next, the 40 hot yoga group members were divided
into the following two groups according to the difference inthe flooring material of the studio where the hot yoga was
performed;
The wood stone studio (WSS) group: 20 participants
who participated in hot yoga on the wood stone floor.
Hot yoga on regular floor (RF) group: 20 participants.
Subjects in the WSS group and subjects in the RF group
took a 60-minute hot yoga lesson under the guidance of an
instructor in an indoor environment with room temperaturearound 35 °C and humidity around 60 % at a designated hot
yoga studio LAVA store at least twice a week for 12 weeks(from May to August, 2021). Subjects were allowed to choose
either the beginner program or the basic program dependingon their individual physical condition on the first day of the
program. The programs that were implemented are shown in
Table 1.
Overall body structure measurements (weight, BMI,
body fat percentage), site measurements (circumferenceof waist, hips, bust, arms, thighs, and calves), flexibility
measurements (forward and backward bending), skinmeasurements (skin water content, VISIA image analysis),and aging-related marker measurements (SIRT1, SIRT 2,
SIRT3) before and 12 weeks after study initiation SIRT6,hTERT, hTERC, 8-OHdG, and ROS), stress assessment (SF8 ), blood pressure measurement, blood biochemistry, andhematological tests were performed. Subjects recorded thepresence and severity of adverse events and lifestyle habitsduring the study period in a daily logbook.

_ 74 _Glycative Stress Research

Subjects with content obtained and pre-testing conducted: 91 cases

Nonconformity with selection criteria: 26 cases
Conflict with the exclusion criteria: 5 cases
Total: 31 cases

Subjects incorporated into this study: 60 cases
Control group: 20 cases
WSS group: 20 cases
RF group: 20 cases

Reason for dropout(due to subject's convenience): 6 cases
WSS group: 3 cases
RF : 3 cases

Subjects who completed the study: 54 cases
Control group: 20 cases
WSS group: 17 cases
RF group: 17 cases

FAS: 54 cases

Excluded from analysis by the Committee
Control group: 1 cases

PPS: 53 cases

Fig. 1. Number of examinees.

WSS, woodstone studio, RS, regular floor; FAS, full analysis set; PPS, per protocol set.

Fig. 1_ 75 _

Physical and Mental Effects of Hot Yoga: A Controlled Open-label Study

Table 1. Hot yoga implementation program (choice of three programs below)
YOGA BEGINNER
Block of Yoga sequence1

session preparation instructions

2warm-up

Yoga Poses Names (Asanas) in Sanskrit & English
session preparation instructions

Duration
1.5 minwarm-up-Breath

6.5 min-Shoulder joint-SpineDandayamna Bharmanasana ／3Asana-Prone

Balancing Table Pose sequence

7.0 minincluding a preparatory pose (hip strech) andfollow-up pose (child pose)

Anjaneyasana ／ Low lunge sequence

including a preparatory pose (twist pose) and

6.0 minPhalakasana ／ plank pose

0.5 min7

Salabhasana ／ Locust pose

0.5 min

9

Adho Mukha Shvanasana ／ Downward-facing dog

4
5
6

follow-up pose (half sprit).

Asana-Sitting

8

14
15

Asana-Standing

18
19
20
21
22

Utthita Trikonasana ／ Extended triangle pose sequence

Asana-Sitting

14.0 minPhalakasana ／ plank pose

0.8 minDhanurasana ／ Bow pose

0.8 min

0.8 minArdha Bhujangasana ／ Half cobra pose
Balasana ／ Child's pose

Upavistha konasana ／ Wide-angle seated forward bend

Cool-down

Relaxation

1.0 minincluding four preparatory Poses (high lunge, eagle pose,wild-legged forward bend, and Squat)

16
17

0.8 min

Uttanasana ／ Standing Forward Bend1213

0.8 minBalasana ／ Child's pose

1011

0.5 min

Bhujangasana ／cobra pose

Ardha Setubandhasana ／ half bridge pose

Eagle twist with hip strech

0.8 min
0.8 min
5.0 min

Shavasana ／ Corpse Pose
Breath_ 76 _

6.0 min
3.5 min

Pawanmuktasana ／ Wind-relieving posesession closing instructions

0.8 min

1.0 mintotal

1.0 min

60.0 minGlycative Stress Research

YOGA BASIC
Block of Yoga sequence1
2

session preparation instructions

3

session preparation instructions

1.0 minJathara Parivartanasana ／ Revolved belly pose

2.0 minBreathwarm-up10

Anjaneyasana ／ Low lunge

11

Parighasana ／ Gate pose

13

Utkatasana ／ Chair pose

Asana-Standing

1.5 min
1.0 min
1.5 min
1.5 min
1.0 minParivrtta Sanchalasana ／ Low lunge twist pose

1.0 min

Virabhadrasana Ⅱ／ Warrior Ⅱ Pose

Natarajasana ／ Lord of the dance pose

25

Tadasana ／ Mountain pose

Asana-Prone

1.0 min
1.0 minDekasana ／Airplane pose

1.0 minDhanurasana ／ Bow Pose

1.0 minBalasana ／ Child's pose

1.0 min

Ustrasana ／ Camel pose31

1.0 min

Sasangasana ／ Rabbit pose

32

2.0 minUpavistha konasana ／ Paschimottanasana

33
Asana-Sitting

1.0 minKrounchasana ／ Heron pose

1.0 minArdha Matsyendrasana ／ Half lord of the fishes Pose

1.0 minPaschimottanasana ／ Seated forward bend

36
Cool-down

1.0 minArdha Setubandhasana ／ half bridge pose

1.0 min

Pawanmuktasana ／ Wind-relieving pose

2.0 min

Pawanmuktasana ／ Wind-relieving pose

39
Relaxation

5.0 min

Shavasana ／ Corpse Posesession closing instructions
total_ 77 _

2.0 min

1.0 min

Bhujangasana ／cobra pose27

1.5 min

2.0 minPhalakasana ／ plank pose26

1.0 min

1.5 minVrksansana ／ Tree pose24

41

1.5 minParsvottanasana ／ Intense side stretch pose

2340

4.0 min

Prasarita Padottanasana ／ Wide Legged Forward Bend

2238

1.0 minUtthita Trikonasana ／ Extended triangle pose

2137

2.0 minGarudasana ／ Eagle pose

1735

2.0 minTadasana ／ Mountain pose

1634

1.0 minParivrtta utkatasana ／chair twist pose

1530

1.0 minArdha chandrasana ／ Half moon pose

1429

1.5 minBalasana ／ Child's pose

1228

1.5 minBalasana ／ Child's pose

920

2.0 minParsva balasana ／ Thread the needle

Uttana Shishosana ／ Extended Puppy Pose

19

1.0 minMarjarasana ／ Cat cow pose

818

1.0 min

Kapalahbhati ／ Skull-shining breath5
7

Duration

Pawanmuktasana ／ Wind-relieving pose

4
6

Yoga Poses Names (Asanas)

1.0 min

60.0 minPhysical and Mental Effects of Hot Yoga: A Controlled Open-label StudyPELVIC ALIGNMENT YOGA
Block of Yoga sequence
1
2
3
4
5
6
7

Session preparation instruction
Neck stretching

Loosen the joints of the feet,plantar flexion and dorsiflexion
Loosen the hip joint

10
11
12
13

Loosen the pelvis
Psoas major training

16
17

Back training

Core training

32
33
34

Ankle rotation

Pull and stretch the hip joint
Sole pose

8.0 minRaising and lowering the ischium
Round and bend back8.0 min

Waist rotation

Psoas major muscle training

2.0 min

Lunge pose
Bow poseChild's pose

3.0 minDownward-facing dog

Downward-facing dog

13.0 min

Swan pose

Wind Relieving pose26

31

5.0 min

Twist pose

25

30

Internal / external rotation of the hip joint

Downward-facing dog

24

29

Plantar flexion and dorsiflexion of the ankle jointChild's pose

2128

3.0 min

Balance pose

20

27

Rotate the neck while breathing

Cat pose

1923

2.0 min

Frog pose

18

22

Session preparation instruction

Raise and lower legs with prone position

14
15

Duration

Hip joint internal rotation stretch

89Yoga Poses Names in English

Spine stretch
Hip joint stretch
Pelvic / spine stretch
Relaxation

Half lotus pose
Side bending

5.0 min

Bridge pose

Wind Relieving pose

4.0 min

Adductor muscle stretch
Spinal rotation

2.0 minCorpse pose

5.0 minSession closing instuctions
total_ 78 _

60.0 minGlycative Stress Research

Assessment Items

Measurement of aging-related markers
As previously reported 1), expression levels of hTERT,hTERC and sirtuin genes (SIRT1, SIRT6 ) were measured inblood samples by real-time PCR. 8-OHdG was detected inplasma samples using a highly sensitive ELISA kit (Nikken
Zyle, Shizuoka, Japan) and ROS was detected in plasma
samples using an OxiSelect TM In Vitro ROS/RNS Assay
Kit (Cosmo Bio, Tokyo, Japan) was used to measure ROS
and RNS, respectively. Measurements were performed at theJapan Clinical Trial Association (Tokyo).

Skin measurement
For skin properties and functional evaluation, stratum
corneum water content was measured, and spots and wrinkles
were measured by image analysis. For these measurements,
after washing the face with a commercially available cleanser,
the skin was allowed to acclimate by resting for 20 minutes
in a room maintained at a temperature of 21 ± 2 °C anda humidity of 50 ± 10 RH %. Skin moisture content wasmeasured using a Corneometer (CM825; Courage & Khazaka,Köln, Germany), and the measurement site was the cheek.
Facial skin images were analyzed using VISIA Evolution(Canfield Imaging Systems, Fairfield, NJ, USA) to evaluate
blemishes (light spots), wrinkles, uneven coloration (texture),
pores, and porphyrins. The measurement area was the entire
face.

Stress assessment
Stress assessment was evaluated with the Japaneseversion of the SF-8 health-related quality of life scale.

Body Structure
Body weight and body fat percentage were measured
using a body composition analyzer (BC-313; Tanita, Itabashiku, Tokyo). The circumference of the waist, hips, bust, arms,
thighs, and calves were measured by the examiner using
a contact method with a tape measure. Flexibility wasmeasured in forward bending and backward bending by
the examiner using a contact method with a tape measure(measuring the distance between the fingertips and the floor
surface).

Blood pressure
Systolic and diastolic blood pressures were measured.

Blood biochemistry
Blood samples were used to measure the following: total
protein (TP), albumin, total cholesterol, triglycerides (TG),
aspartate aminotransferase (AST), alanine aminotransferase(ALT), and albumin. alkaline phosphatase (ALP), leucine
dehydrogenase (LDH) [ IF CC], γ -glutamyl trans peptidase(γ - GTP), creatine phosphokinase (CPK), total bilirubin,
urea nitrogen creatinine, sodium (Na), potassium (K),chlor, calcium (Ca), inorganic phosphorus (P), serum blood

sugar, HbAlc [NGSP], low-density lipoprotein cholesterol(LDL-C), high-density lipoprotein cholesterol (HDL- C),uric acid (UA), insulin-like growth factor- I (IGF-I).

Hematological tests
The following items were measured using blood samples:white blood cell count, red blood cell count, hemoglobin,
hematocrit, platelet count, MCV (mean corpuscular volume),
MCH (mean corpuscular hemoglobin), and MCHC (meancell hemoglobin concentration). Blood biochemical tests andhematological tests were performed at the Japan Clinical
Trial Institute (Shinjuku, Tokyo).

Statistical analysis
Statistical analysis was performed using Excel statistics(Social Information Service, Tokyo, Japan) and a paired-t
test. Corresponding t-tests were used to compare each item
to its pre-test, and Student's t-tests were used to compare
the change in each group from pre-test to 12 weeks posttest. Data multiplicity was not considered and there were
no missing values. Both tests were two-tailed, and a risk
rate of less than 5 % (p < 0.05) was considered a significant
difference.

Subject of analysis
The study started with 60 participants, but 6 dropped out
in the hot yoga group (3 in the WSS group and 3 in the RFgroup). In all cases, the reason for dropping out of the study
was discontinuation of participation for personal reasons. Of
the 54 patients in the analysis population (full analysis set:
FAS), one non-intervention control group member had losta large amount of weight (− 7.3 kg) from 62.2 kg before thestart of the study (week 0) to 54.9 kg after 12 weeks, and thecase review committee concluded that it was appropriate to
exclude this person from the analysis.
The efficacy analysis (PPS analysis) included the following;
Control group: 19 subjects, 43.6 ± 10. 3 years old.
Hot yoga group: 34 subjects (WSS group 17, RF group 17),44.1 ± 9. 5 years old.
Safety analysis was performed on all subjects; all 60
subjects who received the intervention at least once were
included in the safety analysis.

Ethical standard
In accordance with the ethical principles based on the
Declaration of Helsinki (revised Fortaleza, October 2013)
and the Ethical Guidelines for Medical Research Involving
Human Subjects (partially revised in 2017), this study wasapproved by the Ethical Review Committee of the Expert
Committee on Pharmaceutical Affairs Law (Committee
Chairman: Hisao Hoga, Attorney at Law) and the consent
explanation document was given to the subject. The purposeand methods of the study were fully explained in writing andorally, and free will consent was obtained in writing fromthe subjects. The study was registered and conducted in the
UMIN Clinical Trials Registry (UMIN #000044157).

_ 79 _

Physical and Mental Effects of Hot Yoga: A Controlled Open-label Study

Results

Aging-related marker measurements (Table 2)
After 12 weeks of hot yoga, SIRT6 was significantly
elevated in the hot yoga group compared to the control group( p < 0.001); SIRT1 was significantly elevated in the control
group compared to the hot yoga group (p = 0.034). There
were no significant changes in hTERT, hTERC, 8-OHdG, or
ROS between the control and hot yoga groups. No significant
changes were found between the WSS and RF groups in themeasurement of aging-related markers.

Skin measurements (Table 3)
After 12 weeks of hot yoga, skin water content(+ 21.8 %, p < 0.001), wrinkles (−15.8 %, p = 0.002), texture(+18.3 %, p = 0.002) and porphyrins (− 31.1 %, p = 0.003)
were significantly improved in the hot yoga group comparedto the control group. Skin water content significantly improvedin the WSS group compared to the RF group (p = 0.019).

Mental and physical stress assessment (Table 4)
After 12 weeks of hot yoga, the Health-Related Qualityof Life Scale-SF-8 items “ Vitality” ( p = 0.019), “ Social
functioning” (p = 0.045), “ Role emotional ” (p = 0.003) and“Mental component summary” (p = 0.042) were significantly
higher in the hot yoga group and significantly improved in
the hot yoga group. The health-related quality of life scaleSF- 8 “ Physical component summary” significantly improvedin the WSS group compared to the RF group ( p = 0.030).

Body structure (Table 5)
After 12 weeks of hot yoga, body weight (−1.9 %, p =0.012), BM I (−1.7 %, p = 0.021) and body fat percentage(− 3.4 %, p = 0.002) were significantly lower in the hot
yoga group than in the control group. In the regional
measurements, circumferences of the waist (− 5.4 %, p <0.001), hips (−2.0 %, p < 0.001), bust (− 2.4 %, p < 0.001),
arms (−3.5 %, p < 0.001), thigh (− 4.4 %, p < 0.001), andcalf (−1.7 %, p = 0.046) were significantly lower in the
hot yoga group than in the control group. With regard toflexibility, the distance between forward bending ( p < 0.001)
and back bending (p = 0.018) was significantly shorter inthe hot yoga group than in the control group. No significant
changes were noted between the WSS and RF groups in the
body structure measurements.

Table 2. Aging-related markers.

Items

Comparison of before and after

Group

n

Control
SIRT1

Hot yoga

Control
SIRT6

Hot yoga

ControlhTERT

Hot yoga

ControlhTERC

8-OHdG(ng/mL)ROS(nM)

Hot yoga

Control

Hot yoga

Control

Hot yogaSE, standard error.

19
WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17

Mean

0w

SE

2.87 ± 0.21
3.16 ± 0.20

3.12 ± 0.32
3.20 ± 0.24
1.59 ± 0.24
1.48 ± 0.18

1.50 ± 0.26
1.46 ± 0.23

3.98 ± 0.26
3.93 ± 0.20
3.95 ± 0.31
3.91 ± 0.26

2.76 ± 0.16
3.80 ± 0.24
3.82 ± 0.38
3.78 ± 0.29

0.16 ± 0.02
0.15 ± 0.01
0.13 ± 0.01
0.16 ± 0.03

78.56 ± 0.96
77.73 ± 1.19
77.54 ± 1.72
77.92 ± 1.63

Mean

12 w

SE

5.23 ± 0.51
4.23 ± 0.26
4.52 ± 0.41
3.94 ± 0.31

2.32 ± 0.18
4.98 ± 0.31

4.76 ± 0.47
5.20 ± 0.38

5.48 ± 0.32
5.22 ± 0.27

5.16 ± 0.41
5.28 ± 0.35

3.82 ± 0.22
4.87 ± 0.25

5.08 ± 0.35
4.66 ± 0.34
0.11 ± 0.01
0.12 ± 0.01

0.12 ± 0.02
0.12 ± 0.02

76.74 ± 1.51
70.99 ± 1.03

70.94 ± 1.36
71.05 ± 1.54

_ 80 _

P value
0.000

0.000

0.016

0.016

0.002

0.048

0.000
0.000
0.000
0.000
0.000
0.000
0.003

0.000
0.003
0.003

0.024
0.076
0.051

0.232

0.709

0.232

0.340

0.001

0.019

0.020

0.002

0.048

0.000
0.000
0.000
0.000
0.000
0.000
0.003

0.000
0.003
0.003
0.024
0.076
0.051

0.232
0.709

0.232

0.340

0.001
0.019

0.020

Group
comparison(vs. Control)
Comparisonof changeGroupcomparison(vs RF group)
Comparisonof change

0.034
0.187
0.012

0.299

0.000
0.000
0.000

0.496

0.520
0.490
0.705

0.696

0.978
0.729
0.746

0.575

0.237
0.237
0.750

0.467

0.065
0.139
0.131

0.941

Glycative Stress Research

Table 3. Skin measurements.

Items

Skin watercontent

Comparison of before and after

Group

n

Control

Hot yogaRF

Control
Spot

WSS
RF

Control
WrinklesHot yoga
WSS

Control

Hot yoga
WSS

Control

Hot yoga

17

WSS

Control

Hot yogaRF

35.47 ± 1.60

116.29 ± 9.14

17114.62 ± 8.09

113.38 ± 6.63

45.70 ± 2.11

132.92 ± 9.37

0.000

0.399

120.94 ± 8.04

0.006

91.41 ± 4.80

0.000

99.18 ± 7.12

0.002

7.67 ± 0.67

0.009

7.76 ± 0.96

0.027

825.81 ± 57.51

0.537

115.88 ± 6.98

132.26 ± 10.19

102.59 ± 4.41

83.65 ± 5.86

8.33 ± 1.03

7.50 ± 0.94

6.48 ± 0.61

17

6.86 ± 0.85

6.11 ± 0.86

7.58 ± 0.93

19865.63 ± 72.04

900.24 ± 65.39

17809.85 ± 101.35

191146.03 ± 113.24

1253.50 ± 125.58

171484.47 ± 190.75

1016.32 ± 167.94

839.63 ± 66.04
869.41 ± 84.09

1329.81 ± 124.98
1175.15 ± 152.58

0.150

118.41 ± 5.34

118.00 ± 5.81

34

17

0.000

0.001

108.60 ± 4.72

17

0.239

42.66 ± 2.60

34

17

0.239

37.51 ± 2.56

17

34
WSS

SE

0.000

129.38 ± 9.82

17

Mean

P value

44.18 ± 1.69

121.38 ± 6.08

17

12 w

36.28 ± 1.45

34

34
RF

Porphyrins

35.04 ± 1.29

19

RF

Pores

17

19

RF

Texture36.54 ± 1.75

19

Hot yoga

SE

19
34
WSS

Mean

0w

817.21 ± 91.88

0.694

0.098

0.001
0.066
0.076
0.721

0.828

834.41 ± 69.12

0.250

915.84 ± 105.02

0.000

815.35 ± 121.36

0.000

SE, standard error.

_ 81 _

0.426

0.020

0.000
0.001
0.150

0.399
0.694

0.006
0.098

0.000
0.001

0.002
0.066

0.009
0.076

0.027
0.721

0.537

0.828

0.250
0.426

0.000
0.020

0.000

Group
comparison(vs. Control)
Comparisonof changeGroupcomparison(vs RF group)
Comparisonof change

0.000
0.000
0.000

0.019

0.105
0.275
0.039

0.121

0.002
0.001
0.003

0.578

0.002
0.015
0.004

0.517

0.626
0.790
0.493

0.347

0.003
0.015
0.005

0.589

Physical and Mental Effects of Hot Yoga: A Controlled Open-label Study

Table 4. Mental and physical stress assessment.

Items

Physicalfunctioning(PF)
Role physical(RP)

Bodily pain
(BP)

General health
(GH )

Group

Socialfunctioning(SF)

Role emotional(RE)

Mental health(MH)
Physicalcomponent
summary (PCS)nControl

Hot yoga

Control

Hot yoga

Control

Hot yoga

Control

Hot yoga

Control
Vitality (VT)Comparison of before and after

Hot yoga

Control

Hot yoga

Control

Hot yoga

Control

Hot yoga

Control

Hot yoga

19
WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

Control
MentalHot yogacomponent
WSS
summary (MCS)
RF

34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17

Mean

0w

SE

51.90 ± 1.43
51.16 ± 0.68

51.93 ± 0.92
50.39 ± 0.96

52.34 ± 1.00
51.47 ± 0.73

52.29 ± 1.00
50.64 ± 1.01
52.65 ± 1.83
51.83 ± 0.92

50.45 ± 1.48
53.21 ± 0.99

51.07 ± 1.29
51.47 ± 0.86

50.95 ± 1.46
51.98 ± 0.90
51.83 ± 1.26
51.91 ± 0.75

51.17 ± 1.12
52.65 ± 0.95

51.84 ± 1.54
49.94 ± 1.24

50.06 ± 1.67
49.82 ± 1.82

51.75 ± 1.08
50.02 ± 0.96
49.34 ± 1.36
50.69 ± 1.32

50.55 ± 1.46
50.45 ± 0.90

50.63 ± 1.26
50.27 ± 1.30

51.31 ± 1.37
50.81 ± 0.60

50.85 ± 1.01
50.77 ± 0.64
49.99 ± 1.32
49.10 ± 0.97

48.76 ± 1.48
49.43 ± 1.24

Mean

12 w

SE

52.60 ± 0.67
53.13 ± 0.38

53.94 ± 0.32
52.31 ± 0.64

52.79 ± 0.82
53.00 ± 0.53

54.45 ± 0.40
51.55 ± 0.85

50.34 ± 1.89
53.03 ± 0.96
53.86 ± 1.31
52.20 ± 1.38

52.41 ± 1.37
54.75 ± 0.60

55.53 ± 0.96
53.98 ± 0.67

51.51 ± 1.54
54.44 ± 0.64
53.72 ± 1.03
55.17 ± 0.74

51.20 ± 1.87
52.68 ± 1.08

53.93 ± 0.89
51.42 ± 1.92

50.60 ± 1.33
52.71 ± 0.69

52.35 ± 0.99
53.07 ± 0.96

50.30 ± 1.34
52.84 ± 0.83

51.67 ± 1.20
54.01 ± 1.08

51.53 ± 1.19
52.38 ± 0.57

54.06 ± 0.78
50.70 ± 0.59
49.25 ± 1.67
51.89 ± 0.97

50.73 ± 1.37
53.05 ± 1.30

SE, standard error.

_ 82 _

P value
0.564

0.564

0.046

0.046

0.005

0.059

0.634

0.064
0.085
0.419

0.197

0.312

0.053
0.521

0.278

0.000
0.003

0.044
0.690

0.007

0.067

0.055

0.582

0.026
0.023

0.379

0.235

0.001
0.033
0.011
0.822

0.010
0.438

0.004
0.890

0.048

0.007

0.949
0.621

0.001
0.159

0.000

0.005
0.059

0.634

0.064
0.085
0.419

0.197

0.312

0.053
0.521

0.278

0.000
0.003

0.044
0.690

0.007
0.067
0.055

0.582

0.026
0.023
0.379

0.235

0.001
0.033
0.011
0.822

0.010
0.438

0.004
0.890

0.048

0.007
0.949
0.621

0.001
0.159

0.000

Group
comparison(vs. Control)
Comparisonof changeGroupcomparison(vs RF group)
Comparisonof change

0.353
0.388
0.423

0.948

0.377
0.260
0.747

0.445

0.101
0.021
0.578

0.057

0.191
0.079
0.668

0.119

0.019
0.069
0.060

0.983

0.045
0.025
0.297

0.344

0.003
0.014
0.008

0.685

0.067
0.455
0.015

0.124

0.455
0.128
0.879

0.030

0.042
0.181
0.014

0.298

Glycative Stress Research

Table 5. Body composition.

Items

Body weight
(kg)

Group

Body fatpercentage (%)

Hot yoga

Hot yoga

Control

Hot yoga

Control
Waist (cm)

Hot yoga

Control
Hips (cm)

Hot yoga

Control
Bust (cm)

Hot yoga

ControlArms (cm)

Hot yoga

ControlThigh (cm)

Hot yoga

ControlCalf (cm)Forwardbending (cm)Back bending(cm)nControl

Control
BMI

Comparison of before and after

Hot yoga

Control

Hot yoga

Control

Hot yoga

19
WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
20
34
17
17
19
34
17
17
19
34
17
17

Mean

0w

SE

66.09 ± 2.02
64.89 ± 1.23

64.46 ± 1.50
65.33 ± 1.94

26.39 ± 0.84
25.67 ± 0.39

25.81 ± 0.50
25.53 ± 0.60

37.54 ± 1.13
36.66 ± 0.74

37.24 ± 1.00
36.08 ± 1.08

89.42 ± 2.22
89.56 ± 1.19
89.35 ± 1.43
89.77 ± 1.90

100.66 ± 1.57
99.60 ± 0.94

100.09 ± 1.15
99.11 ± 1.47
97.12 ± 1.78
95.02 ± 0.91

95.10 ± 1.14
94.94 ± 1.42

29.97 ± 0.94
29.11 ± 0.37

28.95 ± 0.48
29.28 ± 0.56
51.83 ± 1.11
51.81 ± 0.68
52.11 ± 0.96
51.51 ± 0.95

37.96 ± 0.70
37.97 ± 0.45

37.79 ± 0.61
38.15 ± 0.65
1.50 ± 0.81
4.90 ± 1.05

4.94 ± 1.54
4.85 ± 1.42

117.21 ± 2.24
121.84 ± 1.21
121.74 ± 1.55
121.94 ± 1.85

Mean

12 w

SE

66.13 ± 2.03
63.63 ± 1.20

63.43 ± 1.62
63.83 ± 1.77

26.41 ± 0.89
25.23 ± 0.39

25.50 ± 0.52
24.96 ± 0.57

37.60 ± 1.20
35.40 ± 0.80

36.45 ± 1.01
34.34 ± 1.19

89.83 ± 1.88
84.72 ± 1.14

84.90 ± 1.51
84.55 ± 1.72

100.88 ± 1.44
97.64 ± 0.94
98.61 ± 1.37
96.66 ± 1.24

98.56 ± 1.62
92.77 ± 0.80

92.94 ± 1.14
92.60 ± 1.14

30.65 ± 1.03
28.11 ± 0.36

28.15 ± 0.50
28.06 ± 0.52
52.26 ± 1.07
49.53 ± 0.67

50.15 ± 1.04
48.92 ± 0.80

38.09 ± 0.76
37.32 ± 0.58
37.22 ± 0.61
37.42 ± 0.98
1.95 ± 0.91
2.30 ± 0.73

2.75 ± 0.97
1.85 ± 1.08

117.05 ± 2.46
119.82 ± 1.34

120.06 ± 1.69
119.58 ± 2.08

SE, standard error.

_ 83 _

P value
0.929

0.929

0.004

0.004

0.000

0.015
0.917

0.001

0.015

0.013
0.831

0.000
0.000
0.002

0.585

0.000
0.000

0.001

0.585

0.000

0.019

0.000
0.003

0.000
0.000
0.000

0.007

0.000
0.000
0.000

0.165

0.000
0.000
0.000

0.372
0.074

0.002

0.311

0.225

0.001

0.046

0.006

0.754

0.001

0.020
0.025

0.000
0.015
0.917

0.001
0.015

0.013
0.831

0.000
0.000
0.002
0.585

0.000
0.000
0.001
0.585

0.000
0.019

0.000
0.003

0.000
0.000
0.000
0.007

0.000
0.000
0.000
0.165

0.000
0.000
0.000
0.372
0.074

0.002
0.311

0.225

0.001

0.046

0.006
0.754

0.001

0.020
0.025

Group
comparison(vs. Control)
Comparisonof changeGroupcomparison(vs RF group)
Comparisonof change

0.012
0.036
0.029

0.463

0.021
0.090
0.027

0.280

0.002
0.018
0.003

0.069

0.000
0.000
0.000

0.607

0.000
0.021
0.000

0.217

0.000
0.000
0.000

0.778

0.000
0.000
0.000

0.087

0.000
0.000
0.000

0.260

0.046
0.002
0.245

0.827

0.000
0.023
0.003

0.563

0.018
0.074
0.052

0.557

Physical and Mental Effects of Hot Yoga: A Controlled Open-label Study

Blood pressure (Table 6)

Hematological tests (Table 8)

No significant changes in blood pressure measurements
were found between the control and hot yoga groups.

After 12 weeks of hot yoga, there were no significant
changes in hematological tests between the control and hot
yoga groups.
Red blood cell count (p = 0.008), hemoglobin (p =0.018), and hematocrit (p = 0.034) were significantly higher
in the WSS group than in the RF group.

Blood biochemistry (Table 7)
After 12 weeks of hot yoga, HbA1c was significantly
lower in the hot yoga group compared to the control group(−1.36 %, p < 0.001). Calcium significantly increased in the
hot yoga group compared to the control group (+1.39 %, p =0.005).
HbA1c was significantly lower in the RF groupcompared to the WSS group (p = 0.020). Total protein was
significantly higher in the WSS group than in the RF group(p = 0.022); CK was significantly higher in the RF groupthan in the WSS group (p = 0.028).

SafetyThere were no safety-related adverse events during or
after the study period that were causally related to the use of
hot yoga.

Table 6. Blood pressure.

Items

Systolic bloodpressure(mmHg)
Diastolic bloodpressure(mmHg)

Comparison of before and after

Group

n

Control

19

Hot yogaRF

Control

WSS
RF

SE

117.11 ± 2.35

Mean

SE

P value

118.89 ± 2.05

0.013

0.013

118.76 ± 2.53

0.605

0.605

120.41 ± 1.66

17

120.82 ± 2.48

122.06 ± 2.07

0.225

34

79.26 ± 0.80

80.09 ± 0.59

0.076

80.00 ± 1.09

80.76 ± 0.78

1719

Hot yoga

Mean

12 w

119.56 ± 1.82

34
WSS

0w

17
17

118.29 ± 2.62
80.32 ± 0.89
78.53 ± 1.14

81.11 ± 0.87

79.41 ± 0.84

0.202

0.279
0.114

0.320

0.202
0.225
0.279
0.076
0.114

0.320

Group
comparison(vs. Control)
Comparisonof changeGroupcomparison(vs RF group)
Comparisonof change

0.316
0.242
0.641

0.568

0.968
0.917
0.981

0.898

SE, standard error.

Table 7. Blood biochemistry.

Items

Total protein(g/dL)

Albumin(g/dL)
Total
Cholesterol(mg/dL)

Group

n
19

Control

Hot yoga

Control

Hot yoga

Control

Hot yoga

Control
TG (mg/dL)

Comparison of before and after

Hot yoga

Control

WSS
RF

WSS
RF

WSS
RF

WSS
RF

34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19

Mean

0w

SE

7.40 ± 0.08
7.36 ± 0.05
7.26 ± 0.05
7.45 ± 0.07

4.39 ± 0.07
4.45 ± 0.04

4.37 ± 0.06
4.54 ± 0.04

225.84 ± 9.29
219.24 ± 7.61

Mean

12 w

SE

7.44 ± 0.08
7.34 ± 0.06
7.35 ± 0.08
7.32 ± 0.08

4.37 ± 0.08
4.44 ± 0.04
4.42 ± 0.06
4.46 ± 0.06

217.37 ± 8.94
212.85 ± 6.00

205.88 ± 10.09 206.65 ± 6.79
232.59 ± 10.45 219.06 ± 9.65
122.74 ± 17.31 106.21 ± 14.31

95.21 ± 10.31
83.59 ± 10.86
84 _
119.65 ± 23.48 106.82 ± 17.07
19.16 ± 1.32
17.47 ± 0.70

111.59 ± 14.35
103.53 ± 16.27_

P value
0.520

0.520

0.156

0.156

0.674

0.077

0.736

0.694

0.375
0.149

0.125
0.111

0.887

0.021
0.068
0.223
0.073
0.610

0.056

0.674

0.077
0.736

0.694
0.375
0.149

0.125
0.111

0.887

0.021
0.068
0.223
0.073
0.610

0.056

Group
comparison(vs. Control)
Comparisonof changeGroupcomparison(vs RF group)
Comparisonof change

0.440
0.601
0.076

0.022

0.985
0.370
0.380

0.096

0.751
0.225
0.502

0.066

0.993
0.801
0.888

0.793

Albumin(g/dL)
Total
Cholesterol(mg/dL)Hot yoga

Control

Hot yoga

Control
TG (mg/dL)

AST (GOT)( U/L)ALT (GPT)( U/L)Hot yoga

Control

Hot yoga

Control

Hot yoga

Control
ALP ( U/L)

LDH [IFCC]( U/L)Hot yoga

Control

Hot yoga

Controlγ -GTP ( U/L)CPK (U/L)

Total Bilirubin(mg/dL)Hot yoga

Control

Hot yoga

Control

Hot yoga

Control
BUN (mg/dL)

Creatinine(mg/dL)Hot yoga

Control

Hot yoga

Control
Na (mmol/ L)

Hot yoga

Control
K (mmol/ L)

Hot yoga

ControlC l (mmol/L)

Hot yoga

Control

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

34
17
17
19
34
17
17

19
34

4.45 ± 0.04
4.37 ± 0.06

4.54 ± 0.04
225.84 ± 9.29

4.44 ± 0.04
4.42 ± 0.06

4.46 ± 0.06
217.37 ± 8.94

212.85 ± 6.00
219.24 ± 7.61
205.88 ± 10.09 206.65 ± 6.79
232.59 ± 10.45 219.06 ± 9.65
122.74 ± 17.31
111.59 ± 14.35

106.21 ± 14.31
95.21 ± 10.31

34

83.59 ± 10.86
103.53 ± 16.27±
23.48 106.82 ± 17.07
119.6519.16 ± 1.32
17.47 ± 0.70±
23.65 ± 2.79
0.59
19.06

17

21.71 ± 1.38

17
17
19
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19

19.00 ± 0.74
19.12 ± 0.91

16.16 ± 2.04
17.94 ± 0.99

17.47 ± 1.21
18.41 ± 1.56

71.58 ± 3.96
65.82 ± 2.40

63.18 ± 3.20
68.47 ± 3.45

185.21 ± 5.29
182.12 ± 3.99

181.35 ± 4.88
182.88 ± 6.31
32.63 ± 9.06
24.00 ± 2.93

20.71 ± 3.40
27.29 ± 4.64

96.47 ± 11.05
82.32 ± 5.39

76.35 ± 9.06
88.29 ± 5.47

0.62 ± 0.06
0.52 ± 0.02

0.54 ± 0.04
0.51 ± 0.03

12.81 ± 0.67
15.64 ± 2.73

11.85 ± 0.69
19.43 ± 5.25

0.67 ± 0.02
0.71 ± 0.02
0.72 ± 0.02
0.70 ± 0.02

140.84 ± 0.34
141.00 ± 0.28
141.12 ± 0.46
140.88 ± 0.31
4.48 ± 0.07
4.38 ± 0.05
4.32 ± 0.07
4.43 ± 0.07

103.74 ± 0.49
104.06 ± 0.25

25.59 ± 5.36

0.694

0.694

0.149

0.149

0.375
0.125
0.111

0.887

0.021

0.610

0.056
0.103

0.237

0.054

69.32 ± 3.86

0.141

0.103
0.217

0.311

0.077

67.06 ± 3.38

0.506

187.91 ± 5.19

0.169

186.94 ± 6.22

0.336

196.37 ± 8.81
188.88 ± 8.31

0.116

0.317

30.37 ± 9.09

0.503

29.24 ± 6.41

0.088

121.42 ± 34.20

0.493

27.97 ± 3.94
26.71 ± 4.58

0.136
0.747

97.82 ± 8.36

0.014

116.76 ± 12.73

0.008

0.66 ± 0.05

0.003

0.68 ± 0.07

0.015

11.79 ± 0.52

0.189

78.88 ± 8.69

0.68 ± 0.07
0.65 ± 0.07

11.88 ± 0.79

10.66 ± 0.70

0.673

0.055

0.089
0.153
0.117

12.91 ± 0.65

0.270

0.73 ± 0.01

0.077

0.74 ± 0.02

0.009

141.38 ± 0.28

0.222

0.67 ± 0.02
0.72 ± 0.02

140.84 ± 0.50

0.885

0.777

1.000

141.18 ± 0.36

0.904

4.19 ± 0.05

0.001

141.59 ± 0.42

0.083

4.11 ± 0.03

0.000

4.12 ± 0.05

0.001

4.11 ± 0.03

103.53 ± 0.49

103.00 ± 0.23

± 0.33104.12 ± 0.36 _ 102.71
85 _
103.29 ± 0.31
104.00 ± 0.33
9.14 ± 0.10
9.21 ± 0.08

0.021

0.073

0.223

68.18 ± 4.18

0.887

0.073

0.223

29.65 ± 9.54

67.62 ± 2.69

0.111

0.068

0.092

23.53 ± 4.27

0.125

0.068

18.63 ± 2.86

26.59 ± 5.25

0.375

0.008

0.561

0.000

0.001
0.111

0.172

0.223
0.610

0.056
0.103

0.237

0.054

0.092
0.103

0.223
0.217
0.141

0.311

0.077

0.506
0.116

0.169
0.317

0.336

0.503
0.136

0.088
0.747

0.493

0.014
0.673

0.008
0.055

0.003
0.089

0.015
0.153
0.189
0.117

0.270
0.885

0.077
0.777

0.009
1.000
0.222

0.904
0.083

0.001

0.000
0.008
0.001
0.561

0.000
0.001
0.111

0.172

0.985
0.370

0.096
0.380
Glycative Stress Research
0.751
0.225
0.502

0.066

0.993
0.801
0.888

0.793

0.316
0.379
0.550

0.477

0.255
0.332
0.538

0.505

0.081
0.024
0.740

0.066

0.503
0.717
0.377

0.681

0.146
0.070
0.660

0.084

0.797
0.542
0.925

0.028

0.192
0.543
0.164

0.509

0.325
0.780
0.344

0.367

0.224
0.753
0.053

0.183

0.423
0.923
0.187

0.300

0.762
0.494
0.877

0.399

0.065
0.019
0.373

0.196

Na (mmol/ L)

Hot yoga

WSS
RF

K (mmol/ L)

WSS

Hot yoga

Control
Ca (mg/dL)

Hot yoga

Control
P (mg/dL)

BS (Serum)(mg/dL)

HbAlc [NGSP]
(%)

LDL-C
(mg/dL)HDL -C(mg/dL)Hot yoga

Control

Hot yoga

Control

Hot yoga

Control

Hot yoga

Control

Hot yoga

Control
UA (mg/dL)

IGF - I
(ng/mL)

17
17

0.28
141.12 ± 0.46
140.88 ± 0.31
141.00141.38 ± 0.28
141.18 ± 0.36

141.59 ± 0.42

0.222

0.222

0.083

0.083

0.904

0.904

0.923
0.187

0.300

± of
± 0.05
4.19A Controlled
0.07
ControlPhysical and19Mental4.48
Effects
Hot Yoga:
Open-label
Study
0.001
0.001
0.762
±
4.11 ± 0.03
0.05
4.38
34
Hot yoga
0.000 0.000

ControlC l (mmol/L)

34

Hot yoga

Control

Hot yoga

RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17

4.32 ± 0.07
4.43 ± 0.07

103.74 ± 0.49
104.06 ± 0.25

104.12 ± 0.36
104.00 ± 0.33

9.21 ± 0.08
9.31 ± 0.04

9.34 ± 0.05
9.28 ± 0.06
3.53 ± 0.09
3.39 ± 0.08

3.31 ± 0.12
3.48 ± 0.11

94.11 ± 3.34
91.21 ± 1.48

89.41 ± 2.05
93.00 ± 2.05
5.44 ± 0.12
5.40 ± 0.05

5.35 ± 0.07
5.46 ± 0.07

131.26 ± 7.45
128.09 ± 6.59
117.94 ± 8.13
138.24 ± 9.77

67.63 ± 4.94
66.15 ± 2.47

65.82 ± 3.19
66.47 ± 3.78

4.77 ± 0.25
4.77 ± 0.20

4.75 ± 0.33
4.79 ± 0.24

152.11 ± 9.49
159.12 ± 6.79

4.11 ± 0.03

0.008

0.008

103.53 ± 0.49

0.561

0.561

4.12 ± 0.05

0.001

103.00 ± 0.23

0.000

103.29 ± 0.31

0.111

102.71 ± 0.33
9.14 ± 0.10

0.001
0.172

9.44 ± 0.04

0.007

9.42 ± 0.07

0.099

9.46 ± 0.05

3.56 ± 0.11

3.46 ± 0.08

0.022

0.765

0.393

3.41 ± 0.11

0.387

90.21 ± 3.56

0.243

87.06 ± 1.29

0.199

3.52 ± 0.12

87.56 ± 0.91

88.06 ± 1.26
5.50 ± 0.12

0.738

0.014

0.038

0.030

5.33 ± 0.04

0.005

5.33 ± 0.05

0.002

126.59 ± 5.88

0.652

5.33 ± 0.07
128.47 ± 7.38

120.76 ± 6.20
132.41 ± 9.78

0.548
0.538
0.619

0.102

65.74 ± 4.23

0.264

67.59 ± 3.27

0.444

4.75 ± 0.26

0.900

4.98 ± 0.37

0.094

150.95 ± 9.79

0.812

66.94 ± 2.49
66.29 ± 3.74

4.93 ± 0.21

4.88 ± 0.20

150.03 ± 7.80

161.06 ± 10.08 156.00 ± 12.03
144.06 ± 9.71
157.18 ± 9.07

SE, standard error.

_ 86 _

0.583

0.924
0.152

0.616

0.128

0.648

0.009

0.001

0.000
0.001
0.111

0.172

0.007
0.022
0.099
0.765

0.393

0.387
0.738

0.243
0.014
0.199

0.038

0.030

0.005
0.548

0.002
0.538
0.652
0.619

0.102

0.264
0.583

0.444
0.924

0.900
0.152

0.094
0.616

0.812

0.128

0.648

0.009

0.494
0.877

0.399

0.065
0.019
0.373

0.196

0.005
0.009
0.032

0.898

0.769
0.658
0.952

0.724

0.944
0.678
0.790

0.364

0.000
0.054
0.000

0.020

0.817
0.437
0.589

0.195

0.224
0.199
0.488

0.507

0.357
0.233
0.644

0.538

0.298
0.746
0.076

0.500

Glycative Stress Research

Table 8. Hematological tests.

Items

Comparison of before and after

Group

n

Control
WBC ( /μL)

RBC
( 10 4 /μL)

Hot yoga

Control

Hot yoga

Control
Hb (g/dL)

Hot yoga

Control
Ht (%)

P LT( 10 4/μL)

Hot yoga

Control

Hot yoga

Control
MCV ( f L)

Hot yoga

Control
MCH (pg)

Hot yoga

Control
MCHC(g/dL)Hot yoga

19
WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

WSS
RF

34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17
19
34
17
17

Mean

0w

SE

7184.21 ± 360.84
6508.82 ± 242.91
6270.59 ± 375.34
6747.06 ± 297.41
464.95 ± 7.71
446.38 ± 4.26
440.82 ± 7.35
451.94 ± 3.86

12.87 ± 0.37
13.30 ± 0.16

13.10 ± 0.22
13.49 ± 0.21
39.15 ± 0.85
39.65 ± 0.36

39.22 ± 0.49
40.07 ± 0.52

35.43 ± 1.63
28.78 ± 0.97

26.79 ± 1.13
30.76 ± 1.43

84.60 ± 2.17
88.97 ± 0.97

89.28 ± 1.73
88.66 ± 0.85
27.85 ± 0.93
29.86 ± 0.41

29.86 ± 0.71
29.86 ± 0.39

48.62 ± 15.44
33.54 ± 0.19

33.40 ± 0.28
33.67 ± 0.25

Mean

12 w

SE

6526.32 ± 379.30
5661.76 ± 254.58

5258.82 ± 394.96
6064.71 ± 290.08
465.74 ± 7.39
450.65 ± 4.91

454.94 ± 7.99
446.35 ± 5.52

12.83 ± 0.39
13.34 ± 0.18

13.44 ± 0.26
13.24 ± 0.24

40.05 ± 0.87
40.64 ± 0.44
41.01 ± 0.61
40.26 ± 0.61

50.09 ± 15.87
27.03 ± 0.93
25.19 ± 1.18
28.88 ± 1.30

86.36 ± 2.17
90.36 ± 0.98

90.51 ± 1.71
90.22 ± 0.94

27.71 ± 0.98
29.67 ± 0.40

29.67 ± 0.70
29.66 ± 0.40
31.91 ± 0.42
32.79 ± 0.18

32.75 ± 0.31
32.84 ± 0.17

SE, standard error.

_ 87 _

P value0.019 0.019

0.000 0.000
0.000 0.000
0.025 0.025
0.853 0.853

0.277 0.277

0.012 0.012
0.278 0.278
0.729 0.729
0.767 0.767

0.038 0.038
0.184 0.184

0.040 0.040
0.013 0.013

0.001 0.001
0.736 0.736

0.367 0.367

0.002 0.002
0.022 0.022

0.045 0.045

0.000 0.000
0.000 0.000
0.005 0.005
0.010 0.010
0.365 0.365
0.139 0.139

0.209 0.209
0.374 0.374

0.306 0.306

0.000 0.000
0.001 0.001

0.002 0.002

Groupcomparison(vs. Control)
Comparisonof changeGroupcomparison(vs RF group)
Comparisonof change

0.546
0.298
0.949

0.354

0.546
0.049
0.335

0.008

0.647
0.065
0.365

0.018

0.870
0.148
0.318

0.034

0.314
0.318
0.310

0.790

0.476
0.333
0.762

0.608

0.830
0.850
0.861

0.982

0.327
0.324
0.331

0.523

Physical and Mental Effects of Hot Yoga: A Controlled Open-label Study

Discussion

Summary of results
The effects of a 60-minute hot yoga program twice aweek for 12 weeks on the body of healthy women, who were
aware of their lack of exercise, were examined and compared
to a control group.
The results showed improvement in skin condition(water content, wrinkles, and texture), improvement inphysical and mental stress, improvement in body weight,
shape, and flexibility, decrease in HBA1c, and increase insirtuin gene (SIRT6 ) expression. No adverse events werenoted. These results indicate that hot yoga has a wide rangeof effects and that SIRT6 may be involved in some of themechanisms of action.

Effects of yoga and bedrock on the body
The effects of yoga practice vary depending on thetarget age group, work environment, and presence or absenceof disease. Among the elderly, mental health benefits such as
improved sleep quality 2, 3) and increased social activity 4) wereobserved.
In middle-aged adults, the following effects havebeen reported: alleviation of physical and mental stress 5 - 12),
improvement of sleep quality 10, 12-14), and improvement ofdepressive symptoms 8) .
In young people, there have been reports of stress
reduction 15, 16) and improvement of depressive symptoms 16).
For high school students, yoga was not found to improvephysical and mental stress, however, psychological effects
such as recovery from fatigue, improvement of apathy 17),elevation of mood, and alleviation of negative emotions 18)
have been reported. Many of the students who underwent theyoga program reported that they found it effective.
On the other hand, yoga did not reduce psychosomaticstress in elementary school students 19, 20). It is possible that
there was originally little room for reduction due to thelow psychosomatic stress load. In recent years, due to thecoronavirus outbreak, the response to yoga may be different
from that of schoolchildren, who are more stressed, andfurther investigation is needed.
Tolerance and sensitivity to psychosomatic stress vary
greatly among people and their living environment. Therefore,
it is extremely important to conduct research and accumulate
data on the Japanese population.
A psychological survey was conducted on 74 new yoga
practitioners, and the results showed an increase in selfesteem, satisfaction with life, and motivation to live positively,
and a decrease in interpersonal anxiety and perfectionism 21) .
The bedrock baths popular in Japan incorporate
thermotherapy, a component of hot yoga.
In a study of 13 women (mean age 47. 3 years) lying
down three times for about 10 minutes each time on a hotstone as a bedrock bath, there were no significant changes inpulse wave velocity 22). In a heart rate variability analysis of
21 healthy adult male and female subjects aged 21-36 years,
bedrock bathing significantly increased blood flow rate 23).
In addition, bedrock bathing is associated with a transient
increase in blood glucose as body temperature rises, which
has been shown to be alleviated by drinking water 24). Thisis important information indicating the need for adequate
hydration when administering thermal therapies, including
hot yoga.
In this study, hot yoga improved various SF- 8 stressindicators. Despite the fact that the yoga program was designed
for beginners, it has demonstrated psycho-psychologybenefits.

Role of HSPs
The role of heat shock proteins (HSPs) is important in
the mechanism of action of the thermic effect, one of thecomponents of hot yoga. HSPs are produced in the bodywhen cells are damaged and are involved in the synthesisof proteins necessary for the repair of damaged cells 25) andalso have immunostimulatory effects such as activation of
NK cells 26) . It is assumed to be an important mechanism ofaction for alleviating mental and physical stress, relieving
fatigue, promoting wound healing, and demonstrating
immunostimulating power.
Hsp70 members include cytoplasmic stress-induced
Hsp70 (Hsp72), homeostatic cytoplasmic Hsc70 (Hsp73),
and ER-localized BiP (Grp78) 25) . Hsp70 has ATPase activity,
promotes ATP hydrolysis, enhances peptide binding, andstimulates new protein synthesis. Concurrently, it restoresthe structure of denatured proteins and prevents abnormal
aggregation 27, 28). Unrepairable proteins undergo ubiquitination
and are transported to the proteasome for degradation. As aresult, endoplasmic reticulum stress in the cell is reduced andapoptosis is inhibited.
HSPs also have a positive effect on sleep quality.
In animal studies, administration of HSP 70 close to the
hypothalamus, the control center of the sleep-wake rhythm,
prolongs “slow wave sleep” via GABA receptors and improves
sleep quality 29 -30).
No measurements were made on HSP in this study.
Blood test results showed increased total protein and Hb,suggesting that HSP may increase protein synthesis as aresult of reduced accumulation of abnormal intracellular
proteins and reduced endoplasmic reticulum stress, which inturn stimulates cellular function. Whether hot yoga increases
HSPs or not remains to be verified in the future.

Role of SIRT1
In this study, we measured mRNA for SIRT1 and SIRT6,
two sirtuins derived mainly from leukocytes. SIRT1
functions as an NAD+- dependent protein deacetylase andplays an important role in supplying NAD+, which is essential
for the mitochondrial TCA cycle to function. Progressive
cellular senescence 31) and increased oxidative stress 32)
decrease SIRT1 expression. mRNA-binding protein HuR
normally binds to SIRT1 mRNA 3ʼUTR to form a complex,
but oxidative stress causes the SIRT1-HuR complex to diverge,
resulting in decreased SIRT1 expression 32). Whereas, hypoxia 33)
and exercise 34) increase SIRT1 expression.
AMPK (AMP- activated protein kinase), which isimportant for cellular energy homeostasis, senses changes
in the intracellular AMP/ATP ratio and changes its activity.
When the AMP/ATP ratio increases due to exercise, AMPKis activated, resulting in phosphorylation of the transcriptional
coactivator PGC-1α. An increase in the intracellular NAD+/_ 88 _Glycative Stress Research

NADH ratio is also triggered, leading to an increase in SIRT1
activity. SIRT1 further increases its activity by directly
deacetylating phosphorylated PGC-1α 34). AMPK activation
leads to increased exercise endurance. Thus, exercise
increases SIRT1 expression, creating a virtuous cycle toward
homeostasis of cellular and bodily functions and restorationof diminished function. Attempts to substitute drugs for thisfunction are not recommended.
In the present study, hot yoga resulted in a decrease inbody weight and BMI, and changes in body shape (decreases
in waist, bust, hips, and thigh and lower leg circumference) due
to a decrease in body fat. These effects should be attributed tothe subjects' increased efficiency of energy production during
daily activities and physical activity, homeostasis of glycolipid
metabolism (e.g., improved insulin resistance), and increased
efficiency of fatty acid β-oxidation, in addition to the exercise
associated with postural maintenance (posing) during hot
yoga. In parallel with hot yoga, increasing the amount ofphysical activity in daily life can provide additional benefits.
As for thermal stimulation, it is not known whether
SIRT1 expression is increased, but it promotes the productionof the heat shock protein HSP 70. hsf1 (heat shock factor
1) is a transcription factor for the HSP70 gene. Upon
thermal stimulation, SIRT1 binds to HSF-1 and increases its
transcriptional activity, leading to increased production of
HSP 70 35) .
Although there was no significant increase in SIRT1
expression in the present study compared to the control
group, it is likely that the thermal stimulation of hot yoga
may have promoted the induction of HSP 70 production withan increase in transcriptional activity via the formation of
the SIRT1/HSF-1 complex.
Many people in today's society face a potential lack of
exercise and excessive fat intake. Under these circumstances,
it is extremely important to maintain healthy SIRT1
expression. In the liver, SIRT1 prevents a decrease in
PPARα signaling and fatty acid β-oxidation, leading to theprevention of fatty liver and steatohepatitis 36). In adipose
tissue, SIRT1 prevents increased production of inflammatory
adipocytokines, suppresses inflammatory responses, andleads to the prevention of steatosis 37) .

Role of SIRT6

SIRT6 has NAD+-dependent histone deacetylase (HDAC)
activity, which is characterized by weaker deacetylase
activity and stronger demyristoylation activity than SIRT1,and should be regarded as a lysine deacylase 38). SIRT6
knockout mice had shorter life spans, decreased white blood
cell counts, and decreased bone density, and SIRT6 -deficient
cells were more susceptible to DNA damage 39). Male SIRT6transgenic mice had longer life spans, decreased serum IGF-I
and increased IGFBP1 levels 40) .
SIRT6 has been postulated to stabilize telomeres 41),
regulate the transcriptional activity of NF-kB 42) , andmaintain DNA repair capacity 39). SIRT6 -deficient cells are
more susceptible to DNA damage.
There are few reports on the dynamics of SIRT6 inhumans.
In the area of reproductive medicine, women with reduced
fertility due to impaired ovarian function had lower levelsof SIRT1 expression with no difference in SIRT6 expression
compared to those with other causes 43). In the results ofcyclic fasting in women who wanted to conceive, SIRT1
expression was elevated, but SIRT6 was not affected 44).
Daily consumption of a vitamin D-enriched yogurt drinkfor 12 weeks increased blood levels of SIRT1 and SIRT6 intype 2 diabetic subjects, and the vitamin D plus Ca-enrichedyogurt drink enhanced the increase in SIRT6 45) .
And in the present study, the hot yoga practice was foundto increase SIRT6. Since the results are compatible to thoseof a previous report 1), the findings are highly reproducible.
SIRT6 also affects the GH/IGF-I system; many SIRT6
knockout mice die early in life due to hypoglycemia. SIRT6
knockout mice exhibit phenotypes seen with aging, including
growth retardation, smaller size, low insulin, decreased
lymphocytes, decreased subcutaneous adipose tissue,
decreased bone density, and kyphosis 38). GH/IGF-1 levels are
reduced, contributing to the smaller size of the individuals.
SIRT6 overexpressing mice are significantly longer -lived
males, but not females, than wild-type mice, and have beenreported to have lower IGF-I levels than males of wild-typemice 46). This can be interpreted as a compensatory increasein IGF-I in captive wild-type mice as a result of increased
obesity tendency and insulin resistance due to stress and lackof exercise, while this compensatory increase is restored in
SIRT6-overexpressing mice. SIRT6 overexpressing micealso have higher levels of IGF binding protein 1 (IGFBP-1),
suggesting that SIRT6 is protective against high-fat dietaryload 39) .
Inferring insulin resistance among the three groups inthe present study, the mean waist diameter of the RFr group
was the largest, and insulin resistance may be high. We
interpret this as a significant decrease in serum IGF-I, which
was compensatory elevated in the RF group, due to hot yoga.

Improvement of skin function
The improvement of skin function by hot yoga may be
the result of the combined effects of several factors. The
mechanisms of action include reduction of oxidative stress,
involvement of HSPs, and involvement of SIRT gene expression.
Photoaging accounts for a large portion of skin aging
and involves oxidative stress from UV exposure. In thepresent study, hot yoga significantly reduced ROS ( p =0.065 in group comparison with the control group). UV
exposure and oxidative stress are highly involved in wrinkle
formation 47). It is possible that hot yoga increased tolerance
to oxidative stress and decreased ROS production, resulting
in wrinkle suppression.
It is not known whether SIRT1 expression is increased
for thermal stimuli. However, thermal stimulationencourages SIRT1 to produce HSP70; HSF1 (heat shock
factor 1) is a transcription factor for the HSP70 gene. Upon
thermal stimulation, SIRT1 binds to HSF1 and increases its
transcriptional activity, leading to increased production of
HSP70 48) .
Although there was no significant increase in SIRT1
expression in this study compared to the control group, it isquite possible that the thermal stimulation of hot yoga may
have induced the production of HSP70 through SIRT1.
HSP70 affects skin function. Increased HSP70 in skin_ 89 _

Physical and Mental Effects of Hot Yoga: A Controlled Open-label Study

keratinocytes reduces cellular damage (cell death, inflammatory
response, and DNA damage) caused by UV exposure 49),and increased HSP 70 in pigment cells suppresses melanin
production and reduces the formation of dark spots 50) .
Furthermore, it has been shown that hyperthermia
increases HSP 70 and suppresses wrinkle formation. Since
the ability of cells to induce HSP 70 is decreased in theelderly 51) , it may be advisable to actively incorporate thermal
therapy such as hot yoga in the elderly.
Bipolar fractional radiofrequency (FRF ) therapy is usedin dermatology for the treatment of acne scars, acne vulgaris,
and wrinkle removal. The expression levels of FoxO3 andp53 were reported to be decreased 52) . SIRT6 activity may be
involved in the improvement of skin texture.
In the current study, hot yoga significantly improved
skin water content, wrinkles ( p = 0.002), and texture. The
effects of hot yoga on skin were reproducible, as skin watercontent and texture were also improved in the previous study 1).
We expect that these effects are the result of the synergistic
effects of alleviation of oxidative stress, induction of HSP70,
and increased SIRT6 expression.

was suggested that hot yoga, a combination of moderate heattherapy and yoga physical activity, is a safe treatment that
increases sirtuin activity, acts synergistically with each other,and enhances the efficiency of health promotion effects both
physically and mentally.

Conflict of interest declaration
Support for the conduct of this study was provided by
LAVA International.

Comparison of RF group and WSS group

The comparison between the RF group and the WSS
group showed that the WSS group had significantly better“ Physical component summary ”, a comprehensive index ofsubjective physical symptoms related to quality of life on the
SF-8, and blood tests showed that the WSS group avoided
decreases in RBC, Hb, and Hct, significantly increased total
protein, and had less elevated CPK. These are the advantagesof the Woodstone floors. The only item that showed anadvantage for the RF group was the HbA1c blood test,
which was significantly lower for the RF group (− 2.4 %)but unchanged for the WSS group (− 0.3 %). Considering theabove, it can be inferred that there are more advantages tousing woodstone floors in hot yoga.

SafetyThere were no adverse events attributable to hot yoga
performed under proper supervision and guidance. The
safety of this therapy was confirmed.

Conclusions
Aging, lack of exercise, and excessive fat intake resultin the decline of various cellular and tissue functions,
including the decline of HSPs and sirtuins. As a result,cellular homeostasis is compromised, resulting in reduced
mitochondrial function, accumulation of senescent proteins,and increased endoplasmic reticulum stress. In this study,
a 12-week hot yoga program was administered to womenwith potential physical inactivity and compared to a control
group. The results showed improvement in physical andmental stress, weight loss, body shape, skin condition(wrinkles, texture, moisture retention), and an increase insirtuin SIRT6. In a comparison between RF and woodstone
floors, the latter were estimated to have more advantages. It_ 90 _Glycative Stress Research

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