Glycative Stress Research
Online edition : ISSN 2188-3610
Print edition : ISSN 2188-3602
Received : January 10, 2020
Accepted : March 4, 2020
Published online : March 31, 2020
doi:10.24659/gsr.7.1_75

Original article

Effects of mats with “A Distinctive 4-Layer 3-Dimensional Structure" on sleep
quality, skin function, and fatigue: A non-controlled open-label study
Midori Ando 1), Masayuki Yagi 2), Wakako Takabe 2), Takuto Nonomura 1), Yoji Shimura 1),
Yoshikazu Yonei 2),
1) Japan Research Laboratory of Sleep Science, Nishikawa Co. Ltd., Tokyo, Japan2) Anti-Aging Medical Research Center and Glycative Stress Research Center,
Faculty of Life and Medical Sciences, Doshisha University, Kyoto, Japan

Abstract

Purpose: Results of previous studies suggest that improved sleep quality improves the secretion of growth hormone/insulinlike growth factor-I (IGF-I) and melatonin. In this study, we verified the effects of a mattress with "A Distinctive 4-Layer 3D
Structure" as the study product, on sleep quality, skin quality, and fatigue, through a non-controlled open-label study.
Method: 12 women (age 50.1 ± 4.9 years) with strong subjective and objective findings were selected from among 33 women
who were dissatisfied with sleep and skin quality. A non-controlled open-label study was conducted for changes in physicalinformation when the study product was used for 8 weeks. The study product was provided by Nishikawa Co., Ltd. (Chuoku, Tokyo). Pittsburgh Sleep Quality Index (PSQI-J), Anti-Aging QOL Common Questionnaire (AAQol), verification ofsubjective symptoms using Visual Analogue Scale (VAS), anthropometric measurements, skin moisture, transepidermal water
loss (TEWL), skin viscoelasticity, and blood biochemistry tests were conducted before the commencement of the study and at
4 and 8 weeks after the start of the study. This study was conducted with the approval of the ethics review committee.
Results: PSQI-J showed a significant improvement in sleep quality, time to fall asleep, difficulty sleeping, and daytime
difficulty waking, 8 weeks after the start of the study. The PSQI global score improved significantly from 8.2 ± 1.4 to 4.2 ±
2.2 (p < 0.01). AAQoL and VAS also showed a significant improvement in symptoms related to sleep and fatigue. For skinquality (upper arm), the skin moisture increased significantly after 8 weeks (+35.9%, p < 0.01), and reactivity of TEWL also
increased (+16.9%, p < 0.01). The skin viscoelasticity index R2 increased significantly after 8 weeks ( p < 0.05).
Conclusion: Improvements in subjective symptoms related to sleep and fatigue and improvement in skin quality (moistureand viscoelasticity) were observed with the use of the study product, suggesting that the improvement in sleep quality may
also contribute to cosmetic effects.

KEY WORDS: Sleep quality, skin moisture, transepidermal water loss, skin viscoelasticity, fatigue

PrefaceSleep is essential for maintaining and improving health;however, Japanese people sleep for a fewer number of hours
when compared to other countries. Various studies haveshown that poor sleep quality decreases glucose tolerance
and increases the risk of developing obesity, metabolic
syndrome, and hypertension 1-4). Our research group also
verified whether using a mattress that is suited to the user

improves the health index 5-7). As a result, effects such as
improvement in oxidative stress 6), improvement in glycolipid
metabolism 5, 7), and improvement in the secretion of growth
hormone 5) and melatonin 7) were observed in cases where theuse of a comfortable mattress improved sleep quality. In thisstudy, we focused on skin quality and fatigue, and verified
the effect of a mattress with "A Distinctive 4-Layer 3D
Structure" as the study product, on skin quality and fatigue,
through a non-controlled open-label study.

Contact 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

Phone/ Fax: + 81-774-65-6394 Email: yyonei@mail.doshisha.ac.jp
Co-authors: Ando M, ando-midori@nishikawa1566.com; Yagi M, myagi@mail.doshisha.ac.jp;
Takabe W, wtakabe@mail.doshisha.ac.jp; Nonomura T, nonomura-takuto@nishikawa1566.com;
Shimura Y, shimura-yoji@nishikawa1566.com_ 75 _

Glycative Stress Research 2020; 7 (1) : 75-87(c) Society for Glycative Stress Research

Open-label Trial using mats with “A Distinctive 4-Layer 3-Dimensional Structure”

Methodof a disease for the past one month (excluding thosewith a history of taking temporary-relief medication forheadaches, menstrual pain, and cold)
9) Women with a BMI of 25 kg/m 2 or more
10) Women who may develop seasonal allergy symptoms,
such as hay fever, and may use drugs during the study
period (using eye drops and nasal drops is permitted)11) Women who have a habit of continuous intake ofsupplements and health foods that claim to improve skinquality and fatigue, and who plan to take them during
the study period (however, this does not apply to women
who can stop taking the supplements at the time ofobtaining consent)12) Women who have the habit of drinking alcohol13) Women suffering from alcoholism or other mental
disorders14) Women whose lifestyle may change during the study
period15) Women who plan to stay out overnight (cannot sleep on
the study mattress) during the study period16) Women who cannot avoid intentional exposure to direct
sunlight, such as sunburn, during the study period17) Women who are pregnant, lactating, or who might bepregnant
18) Women who have donated 200 ml of blood in the past
one month, or over 400 ml within the past 3 months
19) Women who have undergone cosmetic treatment within
the past 6 months, or have a previous history of treatment
at the evaluation site20) Women who are currently participating in other humanclinical trials, and those who have participated in otherhuman clinical trials within the past 3 months21) Women who have been determined by the principal
investigator as not suitable to be a subject of this study
The change in the number of study subjects is shown in
Fig. 1.

Subjects

Subjects were healthy women 4 0 to 60 years old,
and we selected 33 women who were aware of mild sleep
disorders such as having difficulty in falling asleep andshallow sleep and worried about skin dryness and resilience.
Preliminary examination (SCR) of the subjects included
anthropometric measurements, hematological tests, generalblood biochemistry tests, special tests for blood and saliva,
urinalysis, skin measurements (skin moisture, transepidermal
water loss [TEWL], skin viscoelasticity, and VISIA image
analysis), skin quality evaluation by a dermatologist, Japaneseversion of the Pittsburgh Sleep Quality Index (PSQI-J), OSA
sleep questionnaire, fatigue Visual Analogue Scale (VAS)
questionnaire, Anti-Aging QOL Common Questionnaire(AAQol), autonomic nervous measurement, and an interview
with a physician. Women who met the selection criteria, did
not violate the exclusion criteria, and had a PSQI-J score of
6 or more were ranked according to the indices (1) and (2),and 12 subjects were selected in order from the one withthe highest overall ranking. (1) From the highest to lowest
PSQI-J score, (2) From the lowest to highest skin moisture.
During selection, outliers and subject background were also
taken into consideration.
The selection criteria are given below.
1) Women 4 0 to 60 years old at the time when the consent
for participation in the study was obtained
2) Healthy women without chronic physical illness
including skin diseases
3) Women who are worried about skin dryness and resilience
4) Women who are aware of mild sleep disorders, such as
having difficulty falling asleep and shallow sleep5) Women with regular bedtime (lights out) and wake-up
time, bedtime (lights out) before midnight, and sleep
habit of 4 hours or more
6) Women with the ability to give consent after receiving
an adequate explanation of the purpose and content of
the study, and who volunteer to participate at their own
accord after proper understanding and provide a writtenconsent to participate in this study.
7) Women who can come on the designated examination
date to undergo examination
8) Women determined to be suitable as a subject of thisstudy by the principal investigator
The exclusion criteria are given below.
1) Women currently suffering from an illness and receiving
drug therapy
2) Women who have skin diseases, such as atopic dermatitis
3) Women with a wound or inflammation at the evaluation
site4) Women with a history of, or currently suffering frommental illness, sleep disorders, hypertension, diabetes
mellitus, dyslipidemia, or a serious illness
5) Women with a history of, or currently suffering from asevere disease of the liver, kidney, heart, lungs, digestiveorgans, or blood6) Women suspected of, under treatment, or previously
treated for Sleep Apnea Syndrome (SAS)7) Women suspected of, or suffering from nocturia andoveractive bladder8) Women who have been taking drugs for the treatment

Study Design
This was a non-controlled open-label study.
The study product was the mattress “AiR SX ” with adistinctive 4-layer 3D structure (Nishikawa Co., Ltd., Chuoku, Tokyo, Japan). The study product was a single size
mattress (9 x 97 x 200 cm) with special sheets provided by
Nishikawa Co., Ltd. The mattresses used by the women werechanged to the study product at the start of the study.
Verification of subjective symptoms, PSQI-J, OSA sleep
questionnaire, fatigue VAS questionnaire, AAQol, skinmeasurements (skin moisture, TEWL, skin viscoelasticity,
and VISIA image analysis), skin quality evaluation by adermatologist, autonomic nervous measurement, anthropometricmeasurements, special tests for blood and saliva, and aninterview with a physician were conducted before thecommencement of the study and at 4 and 8 weeks after thestart of the study. In addition, hematological tests, bloodbiochemistry tests, and urinalysis were also performed before
and 8 weeks after the commencement of the study. The
participants in the study recorded the existence and degreeof adverse events, lifestyle habits, and dietary and exercise
habits during the study period in the life journal. The study
period was from May 2019 to July 2019.

_ 76 _Glycative Stress Research

Women from whom consent was obtained and underwent a preliminary examination
33
Women who did not meet the selection criteria……2
Women in conflict with the exclusion criteria 9
Pittsburgh Sleep Quality Index (PSQI-J)
Women with a score less than 6 points……1
Total 12

Women who could be included in this study
21
Women with an overall ranking of 13thplace or less 9

Women who were included in this study
12

Analysis set
12 women

Fig. 1. Changes in the number of study subjects

g. 1

The age of the 12 women (AiR SX group: women) was 50.1 ± 4.9 years.

Evaluation Items

Subjective Symptoms
PSQI-J was used to evaluate sleep quality 8). The sleep
quality, time to fall asleep, sleeping time, sleep efficiency,
difficulty sleeping, use of sleep inducers, and daytime
difficulty waking were scored according to the scoring
method tabulation table of PSQI questionnaire, and thePSQI global score (PSQI) was calculated. Concerning theevaluation criteria, 5 points or less indicates that there is no
sleep disorder, 6 points or more indicates a sleep disorder,
with 6 to 8 points indicating a mild disorder, and 9 points ormore indicating a severe disorder 9).
The MA version of the OSA sleep questionnaire, a
psychological scale for evaluating introspection at wakeup, was also used (3 days before each observation) 10). The

participants had to fill in numerical values for the 4-stage
evaluation of bedtime, wake-up time, and sleeping time. The
results were tabulated for each of the following factors: First
factor/sleepiness, second factor/sleep maintenance, third
factor/worries, fourth factor/integrated sleep feeling, andfifth factor/sleep initiation.
The evaluation of subjective symptoms before and after
the use of the study product was divided into " physicalsymptoms" and "mental symptoms", and as previously
reported, AAQol was used to evaluate the results with points
1 to 5 in five stages 11).
For fatigue felt on the day of the examination, thesubjects were required to answer on a 100 mm line using
the fatigue VAS test indicated in the Anti-Fatigue Clinical
Evaluation Guidelines of the Japanese Society of Fatigue
Science.

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Open-label Trial using mats with “A Distinctive 4-Layer 3-Dimensional Structure”

Measurement of Skin

Blood Tests

For the evaluation of skin characteristics and function, skinmoisture, TEWL, skin viscoelasticity was measured andspots and wrinkles were measured using image analysis aspreviously reported 12, 13). These parameters were measured
after 20 minutes of acclimatization in a room of constanttemperature and humidity (room temperature 21 ± 1°C,
humidity 50 ± 50%).
Skin moisture was measured on the left cheek (parietal)
and left upper arm using the moisture meter Corneometer(CM825; Courage & Khazaka), and TEWL was measured
using the instrument Tewameter ( TM300®; Courage-Khazaka).
For skin viscoelasticity, the instrument used was
Cutometer (MPA580; Courage & Khazaka). The skin surface
was drawn into the probe opening using negative pressure,and the length of skin that was drawn into the opening wasmeasured using a prism. The measurement sites were the leftcheek (central portion of the lower earlobe and the lip edge)
and right upper arm. The results were expressed as R0, R2,
R5, R6, and R7.
Image analysis of facial skin was performed using
VISIA Evolution (Canfield Imaging Systems, Fairfield, NJ,
USA) and light spots, wrinkles, color spotting (texture),
pores, UV spots, brown spots, red spots, and porphyrin were
evaluated. The measurement site was the left cheek.

The serum levels of insulin-like growth factor-I (IGF-I)
and dehydroepiandrosterone sulfate (DHEA-s) were measured
using blood samples at the Institute of Hoken Kagaku, Inc.
(Yokohama, Kanagawa, Japan).

Evaluation of Skin Quality by a Dermatologist
Visual assessment was performed by a dermatologist
using a dermatoscope (DermLiteDL100; J Hewitt Co.,
Ltd. (Shinjuku-ku, Tokyo)) and microscope (KH-1300/
HXG-2016Z; HIROX Co., Ltd. (Suginami-ku, Tokyo)) The
evaluation of skin hills and skin grooves, and comprehensive
evaluation of the left side of the face (central portion
connecting the lower earlobe and lip edge) was performed forthe visual assessment of skin texture, and evaluation of thedryness, erythema, scale, and irritation itching of the wholeface was performed for evaluation of the skin quality. The
evaluation was performed in 5 stages and assessed using thefollowing criteria.
Skin texture visual assessment: − 2 (poor), − 1 (slightlypoor), 0 (normal), 1 (slightly good), 2 (good) Skin quality
evaluation: 0: "None: no symptoms observed", 1: " Mild :Hardly any symptoms observed", 2: "Slight: Few symptoms
observed", 3: "Moderate: Clear symptoms observed", 4 :"Severe: Significant symptoms observed".

Autonomic Nervous Measurement
Vital monitor VM500 (Fatigue Science Laboratory,
Yodogawa-ku, Osaka) was used to measure the balance andamount of activity (autonomic nervous function age) of theautonomic nervous system.

Anthropometric Measurements
Height, weight, body fat percentage, body mass index(BMI), systolic and diastolic blood pressure, and pulse rate
were measured. The body composition test was performed
using a body composition analyzer (DC-320; Tanita, Itabashiku, Tokyo).

Special Tests of Saliva
The salivary cortisol was measured using saliva samples
at the company Yanaihara Institute Inc. (Fujinomiya,
Shizuoka, Japan).

Statistical Analysis
The statistical analysis was performed with a paired
t-test using statistical analysis software SAS (SAS 9.4; SAS
Institute Japan, Minato-ku, Tokyo) and SPSS (Statistics 25;
IBM Japan, Chuo-ku, Tokyo). The evaluation of skin quality
by a dermatologist, and the scores obtained from PSQI-J,
OSA sleep questionnaire, and AAQol were treated as nonparametric, and a Wilcoxon signed-rank test was performed
for comparison between each group. A risk rate of less than
5% was considered a significant difference, and a risk rateof less than 10% was considered a marginally significant
difference. No outliers were set in particular for outliers andmissing values. However, when data could not be obtained
due to problems during testing or a significant problem
occurred in the reliability of the data, such values wereconsidered as missing values and substitute values were notused.

Ethical Review
This study was conducted in compliance with theHelsinki Declaration (revised at the 2013 WMA General
Assembly in Fortaleza) and the Ethical Guidelines for
Medical and Health Research Involving Human Subjects(Notification of the Ministry of Education, Culture, Sports,
Science and Technology Ministry of Health, Labor andWelfare). This study was approved by holding an ethics
committee meeting for research on human subjects at the"Society for Glycative Stress Research" (Shinjuku-ku, Tokyo),
where deliberation on the ethics and validity of the study was
conducted (GSE 2019-003). The clinical trial for this study
was pre-registered (UMIN #000036774).

Results

Subjective Symptoms
The improvement of subjective symptoms observed withthe use of the study product for 8 weeks was as follows.
In the PSQI -J questionnaire, sleep quality (p < 0.01),
time to fall asleep (p < 0.01), and daytime difficulty waking(p < 0.05) each significantly improved after use of the study
product for 4 weeks and 8 weeks compared to before thestudy, and as a result, PSQIG significantly improved from 8.2± 1.4 (a low-degree disorder) before the study to 4.9 ± 1.6 (nodisorder) after 4 weeks (p < 0.01), and 4.2 ± 2.2 (no disorder)
after 8 weeks (p < 0.01) of using the product ( Table 1).

_ 78 _Glycative Stress Research

Table 1. Sleep quality evaluation.

PSQI -J

Before4 weeks

p value

8 weeks

p valueSleep quality

2.0 ± 0.0

1.0 ± 0.0 **0.001

1.0 ± 0.4 **0.001

Time to fall asleep

1.8 ± 0.6

0.6 ± 0.8 **0.002

0.7 ± 0.7 **0.004

Sleeping time

1.7 ± 0.7

1.7 ± 0.51.000

1.3 ± 0.7

0.157

Sleep efficiency

0.3 ± 0.5

0.1 ± 0.3

0.157

0.1 ± 0.3

0.317

Difficulty sleeping

0.9 ± 0.3

0.8 ± 0.4

0.564

0.7 ± 0.7

0.180

Use of sleep inducers

0.0 ± 0.0

0.0 ± 0.0

1.000

0.0 ± 0.0

1.000

Daytime difficulty waking

1.5 ± 0.8

0.8 ± 0.6*

0.021

0.4 ± 0.7*

0.012

PSQIG

8.2 ± 1.4

4.9 ± 1.6**

0.003

4.2 ± 2.2 **0.006

Results are expressed as mean ± SD, Wilcoxon signed-rank test, n = 12. PSQI-J, Pittsburgh Sleep Quality Index (Japan version) questionnaire; PSQIG, PSQI
global score; SD, standard deviation.

Table 2. OSA Sleep Questionnaire.

OSA Sleep
Questionnaire

Before4 weeks

p value

8 weeks

p valueFirst factor(sleepiness)

39.5 ± 4.4

45.5 ± 6.3 *

0.015

46.2 ± 6.5 *0.015

Second factor(sleep maintenance)

39.4 ± 5.7

49.3 ± 6.8 **0.002

48.4 ± 8. 3 **0.008

Third factor(worries)

49.8 ± 7.1

53.4 ± 6.6

0.103

51.5 ± 7. 5

0.139

Forth factor(integrated sleep feeling)

4 0.0 ± 4.5

46.2 ± 6.8*

0.034

47.1 ± 8.7*

0.050

Fifth factor(sleep initiation)

43.4 ± 5.8

45.1 ± 7.4

0.248

46.6 ± 6.0

0.075

Results are expressed as mean ± SD, Wilcoxon signed-rank test, n = 12. OSA, obstructive sleep apnea syndrome; SD, standard deviation.

In the OSA sleep questionnaire, which is a psychologicalscale for evaluating introspection at wake-up, the following
items improved significantly after the use of the study
product for 4 weeks and 8 weeks compared to before use.
"First Factor (sleepiness)" (p < 0.05 even after 4 weeks and 8
weeks), "Second Factor (sleep maintenance)" (p < 0.01 evenafter 4 weeks and 8 weeks), and "Fourth Factor (integrated
sleep feeling)" (p < 0.05 even after 4 weeks and 8 weeks,
Table 2 ).
The following items of physical symptoms in AAQol
improved significantly after use of the study product for 4
weeks and 8 weeks compared to before use. "Tired eyes"
4 weeks after use (p < 0.01) and 8 weeks after use (p <0.05), "Blurry eyes" 8 weeks after use (p < 0.05), "Stiffshoulders" 8 weeks after use (p < 0.01), "Muscular pain/
stiffness" 8 weeks after use (p < 0.05), "Lethargy" 8 weeks
after use (p < 0.05), "No feeling of good health" (p < 0.05),"Thirst" 8 weeks after use (p < 0.05), "Skin problems" 4weeks after use (p < 0.05) and 8 weeks after use (p < 0.01),"Early satiety" 8 weeks after use (p < 0.05), "Headache" 4
weeks after use ( p < 0.05) and 8 weeks after use (p < 0.05),"Lumbago" 4 weeks after use (p < 0.05) and 8 weeks afteruse (p < 0.05), and "Arthralgia" 4 weeks after use (p < 0.05).
For the mental symptoms of AAQol, the following
items improved significantly after use of the study productfor 4 and 8 weeks compared to before use. "Daily life is not
enjoyable" 8 weeks after use (p < 0.05), "Lose confidence" 8weeks after use ( p < 0.05), "Reluctance to talk with others"
8 weeks after use (p < 0.05), "Depressed" 4 weeks after use(p < 0.05) and 8 weeks after use (p < 0.05), "Shallow sleep"
4 weeks after use (p < 0.01) and 8 weeks after use (p < 0.01),"Difficulty falling asleep" 4 weeks after use (p < 0.01) and8 weeks after use (p < 0.01), "Pessimism" 8 weeks after use(p < 0.05), "Inability to solve problems" 8 weeks after use(p < 0.05), "Inability to make judgments readily" 8 weeks
after use ( p < 0.05), "Inability to sleep because of worries" 8weeks after use (p < 0.05), and "A sense of tension" 8 weeks
after use (p < 0.05) ( Table 3 ).
In the VAS questionnaire of fatigue that described"Fatigue felt at present", there was a significant decrease
after using the study product for 4 weeks (p < 0.05) and 8
weeks (p < 0.01) compared to before use ( Table 4 ).

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Open-label Trial using mats with “A Distinctive 4-Layer 3-Dimensional Structure”

Table 3. AntiAging QOL Common Questionnaire (AAQol).

Physical symptoms
Tired eyes

Before4 weeks

p value

8 weeks

p value

3.8 ± 0.7

2.9 ± 0.9 **0.009

2.8 ± 1.0 *0.017

3.5 ± 1.0

0.070

2.9 ± 0.9 **0.007

Blurry eyes

2.6 ± 1.0

Muscular pain/stiffness

3.3 ± 1.5

No feeling of good health2.4 ± 1.0

Stiff shoulders

2.3 ± 1.3

4.1 ± 0.9

Lethargy

2.8 ± 1.1

3.3 ± 0.9

Thirst2.2 ± 0.8

Early satiety

1.5 ± 0.7

Skin problems

2.8 ± 0.9
2.4 ± 0.8
2.1 ± 0.8

3.3 ± 0.6

Headache

2.3 ± 1.2

Lumbago2.3 ± 0.8 *1.4 ± 0.7

1.9 ± 1.2 *1.8 ± 0.9

Shallow sleep

3.8 ± 0.7

Pessimism

2.5 ± 1.2

Inability to make judgments readily

2.2 ± 0.8

Difficulty in falling asleep
Inability to solve problems

Inability to sleep because of worries
A sense of tension

1.8 ± 0.7**

0.706

1.2 ± 0.4*

0.046

0.020

0.007
0.046
0.014

1.5 ± 0.7*

0.025

2.1 ± 1.1**
1.9 ± 0.9
1.9 ± 0.7

2.0 ± 0.6
1.8 ± 0.7

2.3 ± 1.1

0.024

1.6 ± 0.8

2.5 ± 0.9 **2.4 ± 1.0

0.035

1.6 ± 0.8*

1.6 ± 0.7*

1.5 ± 0.9 *2.1 ± 0.8

0.046

0.160

1.9 ± 1.2

3.6 ± 0.5

0.706

0.028

0.025

2.1 ± 1.1

Depressed

1.8 ± 0.9 *2.3 ± 1.1*

1.7 ± 0.9 *Daily life is not enjoyable

1.6 ± 1.2 *2.0 ± 1.0

1.000

0.248

1.000

2.0 ± 1.0

Reluctance to talk with others

2.3 ± 1.1*

2.1 ± 1.1

Arthralgia

2.3 ± 1.2

0.250

0.034

2.0 ± 1.0 *2.4 ± 1.4 *Lose confidence

2.1 ± 0.8 *0.034

3.2 ± 1.1

Mental symptoms

0.305

1.8 ± 0.7

0.025

0.010

1.6 ± 0.9

0.129

1.6 ± 0.8*

0.046

1.5 ± 0.8*

0.103

0.014

0.007

2.0 ± 0.9 **0.068

1.7 ± 0.9 *0.004

1.8 ± 0.8**

0.157

1.8 ± 0.8*

0.100

1.7 ± 0.5*

0.157

1.7 ± 0.7*

0.206

1.6 ± 0.5*

0.046

0.003
0.003
0.031

0.046
0.034
0.047
0.039

Results are expressed as mean ± SD, Wilcoxon signed-rank test, n = 12. SD, standard deviation.

Table 4. Visual Analogue Scale (VAS) of fatigue.

VAS

Before4 weeks

p value

8 weeks

p value

52.3 ± 22.7

35.9 ± 18.3*

0.039

29. 2 ± 16.4 **0.006

Data are expressed as mean ± SD, paired t test, n = 12. SD, standard deviation.

Skin indicators
Skin moisture increased significantly at the top of theleft cheek (48.61 ± 8.18 → 54.72 ± 9.63, 12.6%, p = 0.038)
and on the left upper arm (20.35 ± 4.28 → 27.65 ± 5.54,
35.9%, p < 0.001) after using the study product for 8 weeks
compared to before use (Fig. 2-a, Table 5 ). TEWL increased
significantly on the left upper arm after using the study
product for 8 weeks compared to before use (7.95 ± 1.57 →9.29 ± 1.59, 16.9 %, p = 0.003, Fig. 2-b).
Concerning the skin viscoelasticity index, R0
significantly increased in the left side of the face (central
portion connecting the lower earlobe and lip edge) and on

the left upper arm after using the study product for 8 weeks
compared to before use (p < 0.05, Fig. 3-a, Table 5 ). R2
significantly increased on the left upper arm after using
the study product for 8 weeks compared to before use (p <0.05, Fig. 3-b). R6 decreased significantly on the left sideof the face after using the study product for 4 weeks (p <0.05) compared to before use, but there was no significant
difference after using the study product for 8 weeks (Fig. 3-c).
Among the visual assessment items by a dermatologist,"Skin hills" showed significant improvement after using thestudy product for 8 weeks compared to before use (p < 0.05),
and "Dryness" showed a marginal improvement after using
the study product for 8 weeks compared to before use (p <_ 80 _Glycative Stress Research

a)a)

b)

Cheek
Cheek

40 40

70 70
60 60

****

* *

50 50

Moisture content
Moisture content

Upper
arm
Upper
arm

35 35
30 30
25 25

40 40
30 30

****

* *

TEWL
TEWL

a)

b)b)

20 20
15 15

20 20

† †

10 10

10 10

5 5

****

0 0

0 0

BeforeBefore4 weeks
4 weeks

8 weeks
8 weeks

BeforeBefore4 weeks
4 weeks

8 weeks
8 weeks

Fig. 2. Skin moisture and TEWL.

a) Skin moisture. b) TEWL. Results are expressed as mean ± SD. *p < 0.05, ** p < 0.01, †p < 0.1 by Wilcoxon signedrank test, n = 12. TEWL, transepidermal water loss; SD, standard deviation.

Fig.
22
Fig.

a)
a)
a)
a)

Cheek
Cheek
Cheek
Upper arm
Upper
Upper arm
arm

0.60
0.60
0.60

R0
R0R0

0.50
0.50
0.50
0.40
0.40
0.40

*
**

0.30
0.30
0.30

**
**
**

0.20
0.20
0.20

0.10
0.10
0.10
1.00
1.00
1.00

b)
b)
b)
b)

BeforeBeforeBefore4 weeks
4 weeks
4 weeks

*
**

R2
R2R2

0.90
0.90
0.90
0.80
0.80
0.80

0.50
0.50
0.50

R6
R6R6

BeforeBeforeBefore***4 weeks
4 weeks
4 weeks

8 weeks
8 weeks
8 weeks

*
**

†
††

4 weeks
weeks
44 weeks

8 weeks
weeks
88 weeks

0.40
0.40
0.40
0.30
0.30
0.30

0.20
0.20
0.20

Fig. 3Fig.
Fig. 33

8 weeks
8 weeks
8 weeks

0.70
0.70
0.70
0.60
0.60
0.60

c)
c)
c)
c)

*
**
**
**
**

0.10
0.10
0.10

BeforeBeforeBeforeFig. 3. Skin elasticity.

a) R0. b) R2. c) R6. Results are expressed as mean ± SD. Skin elasticity measured by Cutometer. * p < 0.05, ** p < 0.01,† p < 0.1 by Wilcoxon signed-rank test, n = 12. SD, standard deviation.

_ 81 _

Open-label Trial using mats with “A Distinctive 4-Layer 3-Dimensional Structure”

Table 5. Skin examination.

Left cheek

Skin moisture

Left upper arm
Left cheek

TEWL g/ hm 2

Left upper arm
R0 Left cheek
Left upper arm

R2 Left cheek
Left upper arm

Skin viscoelasticity

Before4 weeks

p value

8 weeks

p value48.6 ± 8.2

56.1 ± 6.0 **0.003

54.7 ± 9.6*

0.038

18.3 ± 5.1

0.216

17.0 ± 2.7

0.071

20.4 ± 4.3

24.1 ± 5.7*

8.0 ± 1.6

8.7 ± 1.5

21.1 ± 7.2

0.33 ± 0.05**

0.29 ± 0.04

0.36 ± 0.08

0.40 ± 0.05*

0.90 ± 0.02

0.92 ± 0.02*

0.81 ± 0.05

0.81 ± 0.05

R5 Left cheek0.57 ± 0.09

0.54 ± 0.09

R6 Left cheek0.38 ± 0.06

0.33 ± 0.04*

Left upper arm
Left upper arm

R7 Left cheek
Left upper arm

0.92 ± 0.06

0.92 ± 0.09

0.37 ± 0.10

0.34 ± 0.06

0.68 ± 0.04

0.69 ± 0.04

0.41 ± 0.08

0.41 ± 0.06

0.034
0.138

27.7 ± 5. 5**
9. 3 ± 1.6**

0.001

0.32 ± 0.04**

0.904

0.79 ± 0.05

0.025
0.031

0.42 ± 0.10 *0.92 ± 0.02*

0.147

0.54 ± 0.09

0.049

0.34 ± 0.05

0.649

0.4 0 ± 0.07

0.820
0.245
0.157

0.90 ± 0.09

0.000
0.003

0.000
0.011
0.145

0.014
0.141

0.120
0.135

0.32 ± 0.10

0.052

0.68 ± 0.04

0.170

0.315

Data are expressed as mean ± SD, paired t test, n = 12. TEWL, transepidermal water loss; SD, standard deviation.

Table 6. Visual evaluation by a dermatologist qualified doctor.
BeforeTextureSkin hill
Skin groove
Comprehensive evaluation
Dry

Skin quality

Erythema
Scale
Irritation
Itching

4 weeks

p value

8 weeks

p value− 0.3 ± 0.8*

0.014

− 0.3 ± 0.7

0.034−1.1 ± 0.5− 0.5 ± 0.8 *0.020− 0. 5 ± 0.7

0.085

0. 5 ± 0.7

0.2 ± 0.4

0.103

0.3 ± 0.6

0.0 ± 0.0

0.0 ± 0.0

− 1.1 ± 0.5− 0.6 ± 0.8*

− 1.1 ± 0.5

0.3 ± 0.5*

0.8 ± 0.8

0.2 ± 0.4

0.7 ± 1.1

0.0 ± 0.0

0.0 ± 0.0

0.034
0.034
0. 0591. 0001. 000− 0.6 ± 0.7
0.3 ± 0.5
0.3 ± 0.7

0.0 ± 0.0
0.0 ± 0.0

0.131

0.084
0.083

0.285

1.000
1.000

Results are expressed as mean ± SD, Wilcoxon signed-rank test, n = 12. SD, standard deviation.

0.1). The results of "Comprehensive Evaluation" also showeda tendency to improve after using the study product for 8
weeks (p < 0.1, Table 6 ).
However, the results of image analysis by VISIA showeda significant increase in the score of pores after 8 weeks
compared to before use (p < 0.01, Table 7 ).

Autonomic Nervous Measurement
No significant changes were observed with the balanceof autonomous nerves and the amount of activity (autonomic
nervous function age).

Anthropometric Indicators
No significant changes in body weight, BMI, body fat,and blood pressure were observed during the observation
period, but a significant increase in pulse rate was observed
after the study product was used for 8 weeks (p < 0.05)

compared to before use (Table 8 ).

Hematological Tests
The hematological tests showed that MCH (+0.7%, p <0.05) and MCHC (+ 0.8%, p < 0.05) significantly increased
after using the study product for 8 weeks compared to beforeuse ( Table 9 ).

Blood Biochemistry Tests
The blood biochemistry tests showed that Na (+ 0.6%,
p < 0.05), C l (+1.2%, p < 0.05) and HbA1c (+7.9 %, p <0.01) significantly increased after using the study productfor 8 weeks compared to before use. Fe (−18.5%, p < 0.05)
decreased significantly after using the study product for 8
weeks compared to before use. No significant changes wereobserved in liver function, renal function, and serum protein( Table 10 ).

_ 82 _Glycative Stress Research

Table 7. Image analysis of the face skin by VISIA.
Before4 weeks

p value

8 weeks

p value

Skin spots

28. 2 ± 6.1

28.6 ± 7.4

0.759

29.8 ± 8.4

0.368

Texture7. 2 ± 3.4

6.4 ± 2.8

0.273

6.1 ± 2. 3

0.085

Wrinkle25.9 ± 21.1

Skin pores

14. 2 ± 8. 2

UV spots

30.3 ± 4.0

Red spots

35.4 ± 7.7

Brown spots
Porphyrin

20.6 ± 20.8
17.9 ± 10.3*

30.1 ± 4. 9

54.1 ± 4.8

54.6

6.0

5.1 ± 4.9

4. 3

4.1

33.8

10. 2

0.296
0.018

19.6 ± 13.8

18.6 ± 10.6**

0.643

30.4 ± 4.7

0.350

33.5

0.685
0.276

53.6

6.6

5.0

4. 5

8.9

0.184

0. 0020.651

0.694
0. 252

0.873

Data are expressed as mean ± SD, paired t test, n = 12. SD, standard deviation.

Table 8. Anthropometry.
Before4 weeks

Heightcm

159.8 ± 1.2

Body fat
BMI%-

30.2 ± 3.2

30.4 ± 3. 2

Blood pressure(systolic)mmHg

107.8 ± 14.4

Pulse

/min

66.1 ± 10.7

Weightkg

mmHg(diastolic)56.0 ± 4.5
21.9 ± 1.6

66.3 ± 11.0-±

p value-

8 weeks-

55.9 ± 4. 5

0.801

21.9 ± 1.7

0.845

-

56.0 ± 4. 9

0.929

21.9 ± 1. 9

0.911

106.8 ± 15.0

0.647

104.7 ± 7. 5

0. 291

67.3 ± 13.8

0.468

69.4 ± 12.6 *

0.019

65.3 ± 10.1

0.674

63.0 ± 7.8

Before4 weeks

p valueWBC/μL

4875.0 ± 1338.3

5175.0 ± 1317.8

0.422

Hb

g/dL

12.8 ± 0.8

12.6 ± 1.0

0.310

MCV

fL

92.1 ± 5.1

92.0 ± 5.0%

32.2 ± 0.6

32.5 ± 0.7*

Ht

MCH

MCHC
PLT

%

pg

10 4 /μL

432.8 ± 30.0-

30.0 ± 4.1

Table 9. Hematological examination.

RBC

-

0.460

Data are expressed as mean ± SD, paired t test, n = 12. BMI, body mass index; SD, standard deviation.

10 4 /μL±

p value

423.8 ± 34.7

39.7 ± 2.0

38.9 ± 2.7

29.7 ± 1.7

29.9 ± 1.7*

25.6 ± 4.9

25.4 ± 4.9

Data are expressed as mean ± SD, paired t test, n = 12. SD, standard deviation.

_ 83 _

0.107
0.113

0.820

0.044
0.039
0.862

0.611

0.193

Open-label Trial using mats with “A Distinctive 4-Layer 3-Dimensional Structure”

Table 10. Biochemical examination of blood.

TP

g/dL

BUN

mg/dL

ALB
CRE
UA

AST

ALT

γ-GT
ALP

LDH
CPK
CRP

T-Cho
TG

HDL-C
LDL-C
T-BIL
Na
K

Cl

Ca
Fe

GLU

HbA1c

Before4 weeks

p value

6.81 ± 0.29

6.88 ± 0.42

0.412

10.7 ± 1.4

0.901

g/dL

4.03 ± 0.22

mg/dL

0.675 ± 0.068

0.642 ± 0.066

U/L

18.0 ± 2.9

17.3 ± 2.5

mg/dL

10.6 ± 2.4

3.90 ± 0.85

U/L

14.3 ± 4.5

U/L

178.3 ± 61.2

184.3 ± 73.1

U/L

100.6 ± 69.0

mg/dL

200.7 ± 35.8

U/L
mg/dL
mg/dL
mg/dL

20.0 ± 9.9

170.1 ± 24.5

68.0 ± 25.4

62.3 ± 18.2

mEq/L

141.1 ± 1.6

142.0 ± 1.9 *mEq/L

106.2 ± 1.3

107.5 ± 1.6*

μg/dL

122.4 ± 38.5

99.7 ± 29.3*%

5.17 ± 0.30

mg/dL
mg/dL

9.33 ± 0.25

0.338
0.641

0.206
0.214

0.629

0.387
0.859

72.5 ± 20.3

119.1 ± 27.0

4.18 ± 0.22

0.382

204.1 ± 34.9

117.8 ± 22.5

mEq/L

0.543

79.5 ± 27.2

0.045 ± 0.032

0.68 ± 0.15

0.400

167.9 ± 12.7

mg/dL
mg/dL

0.117

21.4 ± 8.4

0.091 ± 0.151

72.1 ± 21.4

0.098

4.13 ± 0.79

15.1 ± 6.1

U/L

0.258

4.11 ± 0.37

0.789

0.194

0.62 ± 0.13

0.020
0.823

4.19 ± 0.22

0.032
0.267

9.40 ± 0.20

86.3 ± 7.6

0.020
0.647

86.8 ± 7.5

0.000

5.58 ± 0.27**

Data are expressed as mean ± SD, paired t test, n = 12. SD, standard deviation.

Table 11. Hormonal examination.
Before4 weeks

p value

8 weeks

p value

serum
IGF-I

ng/mL

127. 3 ± 24.7

128.3 ± 19.8

0.821

124. 2 ± 31. 5

0.587

salivaCortisolμg/dL

0.11 ± 0.03

0. 20 ± 0. 31

0.373

0.11 ± 0.03

0.493

DHEA-sμg/dL115. 3 ± 30.4

106.4 ± 25.0 *

0.018

105.8 ± 33.7*

0.018

Data are expressed as mean ± SD, paired t test, n = 12. IGF-I, insulin-like growth factor-I; DHEA-s, dehydroepiandrosterone-sufate; SD, standard deviation.

Discussion

Blood Tests and Special Tests of Saliva
DHEA-s was 115.3 ± 30.4 μg/dL before use, 106.4 ±25.0 μg/dL after using the study product for 4 weeks and 105.8± 33.7 μg/dL after 8 weeks. There was a significant decrease
after using the study product for 4 weeks (p < 0.05) and 8
weeks ( p < 0.05) compared to before use. No significant
changes were observed for the other items (Table 11).

SafetyAdverse events considered to be caused by the study
product during the observation period were not observed.

Improvement of Subjective Symptoms
A total of 3 clinical studies have been conducted for thisstudy product 5-7), and this is the fourth study. With the use of
the study product, for PSQI-J, a significant improvement has
been observed in the PSQI-J scores of sleep quality, time tofall asleep, difficulty sleeping, and daytime difficulty waking
in all the 3 studies 5 -7). In this study as well, the scores of
sleep quality ( p = 0.001), time to fall asleep ( p = 0.004),
and daytime difficulty waking ( p = 0.012) significantly
improved, and PSQIG improved from a low-degree disorder(8.2 ± 1.4) before using the study product to no sleep disorder_ 84 _Glycative Stress Research(4.2 ± 2.2, p = 0.006). Almost identical results were obtainedin all the 4 studies, indicating that the improvement effect of
the subjective symptoms in this study is highly reproducible.
Measurements using the OSA sleep questionnaire havebeen performed twice so far, and a significant improvementin scores has been observed in the first factor: sleepinessand fourth factor: integrated sleep feeling 5, 7). This study
also showed a significant improvement in the scores ofthe first factor: sleepiness (p < 0.05), second factor: sleep
maintenance (p = 0.008), and fourth factor: sleep initiation(p < 0.05). Significant improvements were observed in thefirst factor: sleepiness, second factor: sleep maintenance,
and fourth factor: integrated sleep feeling in all three studies
as well, showing that the improvement effect of subjective
symptoms for this study is highly reproducible.
A comparative analysis was performed by setting acontrol group in the third study 7), but no control group wasset for this study. This is because it takes effort to set up thecontrol mattress, and a double-blind test is difficult. The
quality of mattress differs significantly from product toproduct. Naturally, if an inferior quality product is used as
the control, it will be easy to identify the difference from thestudy product mattress, and if a superior quality mattress isused as the control, it will be challenging to determine thedifference from the study product mattress.
In this study, various subjective symptoms significantly
improved compared to the mattresses used up to now. We
can infer that drowsiness during the daytime was reduced
as a result of the improvement in "sleep quality" exhibiting
effectiveness in recovery from fatigue. Fatigue significantly
improved in the fatigue VAS questionnaire, confirming thefindings.

Effects on Skin Quality
Skin moisture increased significantly at the top of theleft cheek (parietal) (+12.6%, p = 0.038) and on the left
upper arm (+35.9%, p < 0.001) after using the study productfor 8 weeks compared to before use. TEWL increased
significantly on the left upper arm after using the study
product for 8 weeks compared to before use (+16.9%, p =0.003). Comparing the rate of change for each, an increasein skin moisture (+12.6%) and decrease in TEWL (−19.4%,
no significant difference) were observed on the left cheek(parietal), while an increase in skin moisture (+35.9%) andincrease in TEWL (16.9%) were observed on the left upperarm. If the balance of moisture is considered, the rate ofincrease of moisture exceeds the rate of change in TEWL

at any site. The reason for the increase in TEWL on the left
upper arm was due to an increase in moisture, and it wasdetermined that the skin moisture could be improved, andthe result was judged to be good.
Concerning the skin viscoelasticity index, R0 significantly
increased in the left side of the face (central portion connecting
the lower earlobe and lip edge) and on the left upper arm
after using the study product for 8 weeks compared to beforeuse (p < 0.05). R2 significantly increased on the left upperarm after using the study product for 8 weeks compared tobefore use (p < 0.05). R6 decreased significantly on the left
side of the face after using the study product for 4 weeks (p< 0.05) compared to before use, but there was no significant
difference after using the study product for 8 weeks.
When compared with the characteristics of each index(Table 12) 14), the changes in indices R0 and R5 in this study
indicate that the values are approaching that of a young
person. R6, which showed a decrease after 4 weeks of use, isalso approaching the state of a young person.
In clinical studies using anti-glycation functional
ingredients that reduce glycative stress, skin viscoelasticity
marginally improves in general. When skin collagen fibers
cross-link due to glycative stress, the mobility of collagenfibers and skin viscoelasticity decreases 15, 16). When antiglycation functional ingredients inhibit glycation crosslinking of collagen, the skin viscoelasticity improves. Glycationof the natural moisturizing factor filaggrin causes a decreasein the moisturizing function 17, 18). Preventing the production ofglycated filaggrin can contribute to the improvement of skinmoisture. On the other hand, improvement in "sleep quality"
increases the secretion of melatonin 7), promotes the degradationof Advanced Glycation End-products (AGEs) 19), and reduces
the frequency of glycemic spikes 20), which reduces glycative
stress. From the above, we assume that the improvement in"sleep quality" is linked to the improvement of skin function.
Among the visual assessment items by a dermatologist,"Skin hills" showed significant improvement after using thestudy product for 8 weeks compared to before use (p < 0.05),
and "Dryness" showed a marginal improvement after using
the study product for 8 weeks compared to before use (p <0.1). The results of "Comprehensive Evaluation" also showeda marginal improvement after using the study product for 8
weeks (p < 0.1).
If the results of the moisturizing function, skinviscoelasticity, and diagnosis of the dermatologist are combined,
it can be concluded that the skin quality improved in general.
However, the results of the image analysis of the facial

Table 12. Definitions of skin elasticity indices (cutometer).
Index

Expression

Point of measurement

Skin
0.340

R0

Uf1

Skin length when elongated

R1

Uf1-Ua1

R2

Skin length after elongationand constriction

Ua1/Uf1

Recovery ratio of skin length

R6

Uv1/Ue1

R7

Ratio of viscosity andelasticity when elongated

Ur1/Uf1

Ratio of elasticity during constriction

Hyper - elastic
materials

Meaning of values

0.401

Smaller the value the harder the skin

0.181

0.000

Smaller the value the more elastic the skin

0.468

1.000

The closer to 1.00 the more elastic the skin

0.771

0.056

0.321

0.958

Data quoted from Reference 14).

_ 85 _

Smaller the value the more elastic the skin.
Larger the value the more viscous the skin
The closer to 1.00 the more elastic the skinOpen-label Trial using mats with “A Distinctive 4-Layer 3-Dimensional Structure”

skin by VISIA showed a significant increase in the score
ofpores after 8 weeks compared to before use (p < 0.01). This
study did not reveal how these findings should be evaluated.
This point is a topic for further study.

Relationship between Sleep and Skin
Skin and sleep are interconnected. Though skin pruritus(itching) is a common sensation that everyone experiences,
we cannot refrain from continuous scratching due to thepathological itching associated with the disease, causing adecrease in work efficiency and sleep disorders that often
result in decreased quality of life (QOL) 21-23). Insomnia due tochronic itching in atopic dermatitis and generalized pruritus
becomes a medical problem. Skin itching generally increases
at night, causing difficulty in falling asleep after going to bed.
Scratching in response to itching sensation also occurs during
sleep. Intense scratching in sleep without self-control worsens
skin lesions and further increases the itching sensation. The
prevalence of sleep disorders is significantly higher in patientswith atopic dermatitis and is a serious problem 24-26).
It is essential to ensure "sleep quality" from theperspective of beauty as well. More than 90% of female
university students suffer from acne, and exacerbation factors
include mental and physical stress and insufficient sleep in
addition to irregular diet 27). Concerning skin beauty, chrononutrition based on circadian rhythm is gaining attention.
Unlike conventional nutrition that focuses on nutrient intake,chrono-nutrition gives importance to the effects of time, speed,
and order of meal intake 28). Regular diet and sleep that activate
the clock gene renew the skin by the nocturnal secretion of
growth hormone and melatonin. Abnormal secretions ofhormones such as cortisol due to disturbance in the circadianrhythm and stress, damages the skin. Chrono-nutrition
substantiates that intake of a nutritionally-balanced breakfast
and diet to avoid glycemic spikes is important for skin beauty.
There are interesting reports on the connection between"sleep quality" and the formation of wrinkles 29). The
psychological response to visually evoked emotional stimuli
was analyzed in 39 female subjects who were divided into
insomnia group, insomnia + overeating group (combination of
insomnia and overeating), and control group (healthy subjects).
Stimuli of different valence (positive, negative, or neutral) andstimuli associated with the corresponding symptoms (sleep,
diet, and physique) were shown on the monitor to each subject,electromyogram of the corrugator supercilii muscle and large
zygomaticus major muscles, heart rate, and skin conductivity
were evaluated. As a result, the insomnia group had decreased
corrugator supercilii muscle activity when exposed to positive
stimuli related to sleep. This response is explained to be a
result of desire. This effect was also observed in the control
group having a proper physique and a healthy diet for visual
stimuli. An increase in the corrugator supercilii muscle
activity, which indicates distress, was observed in the control
group in response to negative sleep stimuli, and in insomnia +overeating group in response to negative stimuli related to dietand physique. Increased corrugator supercilii muscle activity
continuously for a long period may lead to facial wrinkling.
Conversely, improved "sleep quality" and reduced corrugatorsupercilii muscle activity may have a preventive action on
wrinkle formation.

Mechanism of How "Sleep Quality"
Improves Skin Quality
In this study, the use of a comfortable mattress improved"sleep quality" and showed an improvement effect onskin quality. The improvement in skin viscoelasticity andmoisturizing function was particularly noticeable. We shallconsider the possible mechanism for this improvement.
Findings from previous clinical studies suggest that theuse of a comfortable mattress improves the "sleep quality"
which affects the endocrine system, leading to an increasein the secretion of growth hormone/IGF-I 5) and melatonin 7),
and decrease in the secretion of cortisol 5). The secretion of
growth hormone promotes the proliferation of keratinocytes,
production of keratin and strengthens the skin barrier function,
thereby improving the moisturizing skin function. Decreased
secretion of cortisol affects immune response cells such as
Langerhans cells to improve the immune function of the skin.
Since cortisol causes an increase in insulin resistance andworsening of glucose metabolism if the secretion of cortisol
is reduced, glucose metabolism improves and glycative stress
reduces. Melatonin has an anti-oxidant effect 30), degradation
promotion effect of AGEs 19), reduction effect of glycemic
spikes 20), and reduces glycative stress. When glycative stressis high, the skin quality deteriorates due to the glycationof skin proteins. Glycation of collagen and elastin reducesskin viscoelasticity, while glycation of filaggrin reduces
moisturizing function. On the other hand, these functions
can be retained if glycative stress can be reduced and protein
glycation can be inhibited. It is presumed that the endocrine
secretion effect and glycative stress-reducing effect achievedby the improvement of "sleep quality" act comprehensively
over 8 weeks, resulting in improved skin quality, such aselasticity and moisturizing.

Conclusion
When a clinical study using the study product was
conducted for 8 weeks with female subjects who were notsatisfied with their current mattress and the effects on skinquality were analyzed, findings such as improvement in skinviscoelasticity and moisturizing function were obtained. The
findings suggested that skin quality improved as a result of
improvement in "sleep quality" by the use of a comfortable
mattress. Based on the results of studies conducted so far,
it is assumed that this improvement is brought about by theeffect on endocrine secretion (increased secretion of growth
hormone/IGF-I and melatonin, reduced secretion of cortisol)and reducing effect on glycative stress.

Conflict of Interest Statement
We received research support from Nishikawa Co., Ltd.
to conduct this study.

_ 86 _Glycative Stress Research

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