AroNap: A Scent-based Nap Promotion System

Mayo Iizuka, Anna Yokokubo

and Guillaume Lopez

Aoyama Gakuin University, Tokyo, Japan

Keywords:

Nap, Sleep Onset, Wake-up, Health Promotion System, Work Efﬁciency.

Abstract:

Compared to other countries, Japanese sleep time is insufﬁcient, and many people have reduced work efﬁ-

ciency due to daytime sleepiness caused by lack of sleep. The government recommends taking a nap as a

countermeasure, but few Japanese do. This study developed a wearable sleep-onset / wake-up promotion sys-

tem, ”AroNap,” that supported a short, effective nap and veriﬁed its effect. AroNap is a system that promotes

falling asleep and waking up during a nap at an appropriate timing by attaching a computer-controlled scent

diffusion device to a neck pillow. To verify the usefulness of AroNap and scent, we conducted an evaluation

experiment to compare the effect on sleep quality of presence or absence of AroNap, the type of scent, and

the sleep state according to the timing of use. We also evaluated the system using the system usability scale

(SUS). Proper use of AroNap has been shown to improve sleep quality compared to other cases.

1 INTRODUCTION

Compared to other countries in the world, Japanese

sleep time is insufﬁcient. Figure 1 shows a compari-

son of average sleep times in each country according

to a 2019 survey by the Organization for Economic

Co-operation and Development (OECD, 2020). Ac-

cording to this survey, the average sleep time in Japan

was 7 hours and 22 minutes. There is a difference of

more than 2 hours between South Africa and Japan,

which have the longest average sleep time. In addi-

tion, there is a difference of nearly 20 minutes com-

pared to South Korea, which has the shortest average

sleep time next to Japan. Therefore, Japan has the

lowest sleep time in the OECD member countries and

can be the country with the shortest sleep time glob-

ally. In addition, the 2019 National Health and Nutri-

tion Survey shows that 37.5% of men and 40.6% of

women sleep less than 6 hours (MHLW, 2020). When

asked about sleep quality in this survey, 32.3% of men

and 36.9% of women answered that they felt drowsy

during the day.

There is a power nap as a countermeasure against

the decrease in work efﬁciency due to daytime sleepi-

ness (PHILIPS, 2019). Power naps are short naps dur-

ing the day, and NASA has demonstrated the scien-

tiﬁc effect of improving cognitive ability by 34% and

attention by 54% (Barry and Phillips, 2006). Global

https://orcid.org/0000-0003-2657-4961

https://orcid.org/0000-0002-9144-3688

Figure 1: Comparison of average daily sleep time in OECD

member countries(Created based on the survey data of

(OECD, 2020)).

companies such as Google and Apple actively encour-

age naps by installing nap spaces and sleep devices in

their ofﬁces to improve work efﬁciency. In Japan as

well, the Ministry of Health, Labor and Welfare stated

in the ”Sleep Guidelines for Health Promotion 2014”

that ”a short nap of 30 minutes or more in the early af-

ternoon is effective in improving work efﬁciency due

to drowsiness.”(MHLW, 2014). However, in Japan,

67.9% of the respondents answered ”I do not have

many days” or ”I do not do it at all” when asked,

”Do you take a nap during work or lunch break?”

(PRTIMES, 2015). Possible reasons for this not be-

ing established include the negative image of taking

a nap at work, securing a nap place, and the cost of

dedicated equipment.

Iizuka, M., Yokokubo, A. and Lopez, G.

AroNap: A Scent-based Nap Promotion System.

DOI: 10.5220/0010826900003123

In Proceedings of the 15th International Joint Conference on Biomedical Engineering Systems and Technologies (BIOSTEC 2022) - Volume 4: BIOSIGNALS, pages 22-30

ISBN: 978-989-758-552-4; ISSN: 2184-4305

In this study, we developed and veriﬁed the use-

fulness of AroNap, a wearable system for promoting

falling asleep and waking up, which supports effective

napping for a short time to improve work efﬁciency.

The results of the evaluation experiments conﬁrmed

that the correct use of the scent by the subjects during

naps has a long-lasting, relaxing effect. The subjects

also conﬁrmed that the scent reduced drowsiness on

waking, helped them recover from fatigue, and en-

abled them to take a good nap. From the evaluation

experiments, we also clariﬁed the issues to be solved

in practical use.

2 RELATED RESEARCH

2.1 Study on Nap

Kaida et al. examined the effects of forced awaken-

ing and self-awakening to reduce sleep inertia after a

short nap (Kaida et al., 2001). Experiments suggest

that self-awakening is effective in suppressing sleep

completion after a nap. Hayashi et al. point out that

the self-awakening of a short nap enhances the effect

of a short nap (Hayashi and Hori, 2007).

A study by Unoki investigating whether short-

term naps relieve psychological and physical stress

showed that psychological stress reactions such as

tension and physical stress reactions such as stiff

shoulders and eye strain were relieved (Unoki, 2017).

In addition, a study comparing the effects of sleep

time on the eve suggests that a short nap during the

day may be effective not only for people who lack

sleep time but also for people who have average sleep

time(Unoki, 2018). Koyama et al. conducted a study

of a short nap in a chair (Koyama et al., 2019). It was

found that there was no difference between the chair

and bed naps in the short nap, and the same drowsi-

ness reduction effect was obtained.

2.2 Nap Introduction System

There are many systems for introducing naps that

have been put into practical use. Yamaha Corpora-

tion has developed a nap support system ”nap sys-

tem” that uses sound and conducts a prototype trial at

Narita Airport in 2019 (Yamaha, 2019). The nap sys-

tem supports falling asleep with a ”good sleep sound”

linked to the biological rhythm.

There is also a nap introduction system called ‘En-

ergy Pod,’ a chair dedicated to power naps, which

have been proven to improve workplace well-being

(Dore et al., 2021). The Energy Pod is designed to

relax, such as weightless position, sleep music, and

gentle light and vibration for comfortable awaken-

ing. However, these systems are expensive and re-

quire ample space for installation, making them difﬁ-

cult to introduce into a company.

2.3 Fragrance Sleep Induction

There are many studies using scents in sleep induc-

tion studies. Yamamoto et al. Applied the sympa-

thetic nerve activity-suppressing effect of the aroma

component cedrol in the essential oils of conifer-

ous trees such as cedarwood to sleep situations (Ya-

mamoto et al., 2003). In a comparative experiment

between placebo and cedrol conditions conducted by

Yamamoto et al., Total sleep time tended to be signif-

icantly prolonged under cedrol conditions, sleep la-

tency was shortened considerably under cedrol con-

ditions, and sleep efﬁciency tended to increase under

cedrol conditions. The sedative effects of cedrol on

sympathetic nerve activity tended to reduce evident

arousal for more than 1 minute in the ﬁrst half of

sleep. From the above, cedrol’s sympathetic nerve

activity inhibitory effect can create an environment

where it is easy to fall asleep.

Yada et al. clariﬁed the inﬂuences of ethnic and

regional characteristics and differences in perception

on the cedrol effect on autonomic nerve activity (Yada

et al., 2007). They found that the miosis rate (ratio

of pupil diameter variation after the light stimulus to

initial pupil diameter) signiﬁcantly increased after ce-

drol exposure compared to that before exposure in all

three countries (Norway, Thailand, and Japan), sug-

gesting that the parasympathetic nervous system be-

came dominant.

Ohno et al. examined the effect of the scent of

black tea on sleep in stress-conscious women (Ohno

et al., 2020). In comparison experiments with placebo

solution and tea aroma solution by Ohno et al., the

quality of subjective sleep, sleep onset, sleep mainte-

nance, fatigue, psychological action to reduce the im-

provement and stress awareness of satisfaction with

sleep time was seen. These experiments strongly sug-

gested that the scent of black tea reduced stress con-

sciousness and facilitated sleep.

2.4 Fragrance Injection Mechanism

There are various methods for presenting scents.

Aroma is one of the typical methods. The aroma can

use in a variety of ways, including candles and dif-

fusers. Some commercially available aroma diffusers,

such as aroma sticks, are smaller and more convenient

to carry

Aromastic, Sony, https://scentents.jp/aromastic/

AroNap: A Scent-based Nap Promotion System

Figure 2: Neck pillow and aroma stone used in AroNap.

In addition, scents have been familiar to Japanese

people since ancient times, and there have long been

a small scent presentation method called a scent bag

and an instrument used for a Kodo called an incense

burner. In the Kodo experience system proposed by

Yokokubo et al., an interactive incense burner has

been developed, and it is thought that there is still

room for development in the efforts of scent and his

interaction (Yokokubo et al., 2019).

3 PROPOSAL SYSTEM:AroNap

AroNap is a system that aims to support short naps

to improve work efﬁciency by promoting sleep onset

and awakening by taking advantage of the character-

istics of the scent. The name of AroNap is a combi-

nation of the smell ”aroma” and the nap ”nap.” The

target users of AroNap are those who need a nap but

cannot easily fall asleep or get up comfortably. Use

for a short nap while sitting in a chair. Also, AroNap

does not require as much space at a high cost as exist-

ing nap systems. You can purchase the products you

are using at mass retailers, and you do not need a ded-

icated place such as your seat or an empty conference

room. AroNap consists of two M5StickC

, a smart-

phone, a commercially available neck pillow

shown

in the ﬁgure 2 and aroma stone

3.1 AroNap Conﬁguration

The hardware of AroNap consisted of an M5StickC

with a Servo HAT mounted sensor and a box for

storing aroma stones (after this referred to as the

AroNap module)(Figure 3). The M5 Stick C controls

the opening and closing of the AroNap module lid

M5StickC, M5Stack, https://shop.m5stack.com/

collections/m5-hat

neck pillow,Muji, https://www.muji.com/jp/ja/store/

cmdty/detail/4550182576221

Aroma stone,Muji, https://www.muji.com/jp/ja/store/

cmdty/detail/4548718959112

Figure 3: AroNap module created with a 3D printer.

Figure 4: M5StickC and ServoHAT connected.

(Figure 4). Servo HAT is a servo motor that opens and

closes the lid.

The AroNap module produced this time has a

cylindrical box with a diameter of 10 cm and a height

of 2.5 cm, and the lid (Figure 5) is a drop shape of

about 8 cm. The AroNap module has circular holes

and rectangular holes. The circular hole is 5 cm in

diameter and 2 cm in height, and the rectangular hole

is 8 cm in length and 2.5 cm in width. Put aroma

stones in the circular holes. Attach the M5 Stick C

and Servo HAT to the rectangular holes. The AroNap

module comes with rubber that is used to attach to the

neck pillow.

The AroNap software was implemented as an

AroNap application used on smartphones (after this

referred to as the AroNap application). The smart-

phone and the AroNap module connect via Bluetooth,

and the smartphone gives instructions to open and

close the lid at the speciﬁed timing.

Figure 6 shows the system conﬁguration of

AroNap. When the user enters the nap time in the

AroNap app and presses the start button, the AroNap

module on the sleep onset promotion side is instructed

to open the lid. After half of the nap time, the

AroNap module on the sleep-onset promotion side is

instructed to close the lid, and 10 seconds later, the

AroNap module on the wake-up promotion side is in-

structed to open the lid. After waking up, pressing the

stop button will instruct the AroNap module to close

the lid of the currently open AroNap module.

BIOSIGNALS 2022 - 15th International Conference on Bio-inspired Systems and Signal Processing

Figure 5: AroNap module opening / closing lid made with

a 3D printer.

Figure 6: AroNap system conﬁguration.

3.2 How to Use AroNap

AroNap is used by attaching the AroNap module to

the neck pillow. Also, download the AroNap applica-

tion to the user’s smartphone and operate the AroNap

module. First, attach the lid of the AroNap module,

and then connect the AroNap module and the smart-

phone via Bluetooth. After conﬁrming the connection

between the AroNap module and the smartphone, put

the aroma stone in the AroNap module and close the

lid (Figure 7).

At this time, the AroNap module on the sleep

onset promotion side contains an aroma stone con-

taining a scent (like cedarwood, lavender) that has a

sleep onset promotion effect. On the other hand, the

AroNap module on the wake-up promotion side con-

tains aroma stones containing a scent (like lemon) that

has a wake-up promotion effect.

Also, set the initial position of the lid to close the

hole containing the aroma stone. Figure 8 shows how

the AroNap module is attached to the neck pillow.

Next, enter how many minutes the user wants to

take a nap in the AroNap app and press the ”TIME

INPUT” button (Figure 9). The default nap time is

20 minutes. Finally, press the ”START” button in the

middle to start AroNap. When nap time is over, press

the ”STOP” button to close the lid of the AroNap

module.

Figure 7: AroNap module with built-in various sensors and

aroma stones.

Figure 8: AroNap module attached to the neck pillow.

4 EVALUATION EXPERIMENT

In order to verify the usefulness of the AroNap and

the scent, we conducted an evaluation experiment to

compare the sleep conditions with and without the

AroNap, the type of scent, and the timing of use. In

addition, we conducted a questionnaire survey after

having subjects use this system.

4.1 Experimental Method

13 subjects (12 males and 1 female in their twenties

and one female in her thirties) were tested to com-

pare their sleep conditions under three experimental

conditions. The minimum number of subjects was

set at about 10. The reason for this is that the min-

imum number of subjects is about 10 in verifying the

relaxation effect brought about by fragrances, as de-

scribed in the ergonomics guide by Tadahiko Fukuda

et al (Fukuda and Fukuda, 2009). There are three ex-

perimental conditions:

• Experiment with AroNap, in which a transition is

made from the fragrance for falling asleep to the

fragrance for waking up.

• Experiment without AroNap, in which a transition

is made from the fragrance for waking up to the

fragrance for falling asleep.

AroNap: A Scent-based Nap Promotion System

Figure 9: Screen example of AroNap app.

• Experiment without AroNap, in which no fra-

grance or AroNap is used.

The three conditions were the ﬁrst-sleep experiment,

the ﬁrst-wake experiment, and the no-sleep experi-

ment. Subjects were asked to participate in all three

conditions, but they were asked to participate in only

two conditions if this was not possible.

The experiment was conducted from 13:00 to

14:00 or 14:00 to 15:00. The pulse interval was con-

stantly measured during the experiment. The sched-

ule for each hour of the experiment was the same: 20

minutes of free time, 20 minutes of napping, and 20

minutes of free time. The ﬁrst 20 minutes of free time

was spent freely in the experimental classroom, but

the location of the last 20 minutes of free time was

not speciﬁed. In the last 20 minutes of free time,

we did not specify the location of the free time and

asked the participants to refrain from strenuous exer-

cise such as running during the free time. Since we

wanted to know the effect of a short nap, we did not

specify the location or the behavior after the nap but

checked whether the participants were motivated to

work or not.

The experiment was conducted in a small class-

room in a university. The classroom size was about

3.5×5, and half of the classroom was divided by a cur-

tain, and the subjects were placed on the backside (A)

and the front side (B). A chair with an extended back-

rest and a headrest was prepared. In the experiment

using fragrances, we organized several fragrances.

We asked each subject to choose their favorite one be-

cause AroNap: A System to Promote Falling Asleep

and Waking Up Using Fragrance Presentation in Nap-

ping suggested that each subject’s preference of fra-

grance may affect their napping (Iizuka et al., 2021).

We prepared two fragrances for falling asleep, and

two fragrances for waking up, and each subject was

asked to choose one of the two fragrances. We pre-

pared @aroma

’s Lavender Mint and Juniper Cedar

for the sleep-in scent, and @aroma’s Clean Citrus and

Orange Grapefruit for the wake-up scent.

After the 20-minute nap, the participants were

asked to answer the Obstructive Sleep Apnea (OSA)

sleep questionnaire (Yamamoto et al., 1999). After

completing two or three experiments, they answered

the System Usability Scale (SUS).

4.2 Evaluation Method

In this experiment, we analyzed the degree of relax-

ation using the pulse interval (RRI), the quality of

sleep using the OSA sleep questionnaire, and the eval-

uation of AroNap using SUS.

The pulse interval is compared using two meth-

ods. The ﬁrst method uses the standard deviation re-

sulting from resampling the acquired data. The 20-

minute value during napping was mainly used for the

pulse interval, and two or three patterns of pulse inter-

vals were compared. If the standard deviation value is

small, it is evidence that the pulse interval is calm, and

it can be said that the person is in a relaxed state.

The second method is to use a Lorenz plot using

the RRI of the resampled acquisition data. In Lorentz

plot the value of RRI(n) is plotted on the x-axis and

the value of RRI(n+1) is plotted on the y-axis. Since

the heart rate increases during exercise, the RRI is

small, and the RRI(n) and RRI(n+1) are almost the

same, the plot is located at the lower left of the graph.

On the other hand, during relaxation or sleep, the

RRI(n) and RRI(n+1) values change signiﬁcantly due

to the large ﬂuctuation of the heart rate sensation, and

the plot position becomes the upper right of the graph.

There are ﬁve factors in the OSA sleep question-

naire, and it is thought that the higher the score, the

better the sleep. Since we are targeting a short nap,

we excluded the values of factors related to dream-

ing. The following are the factors of the OSA sleep

questionnaire:

• Factor 1 Drowsiness when waking up

• Factor 2 Sleep onset and sleep maintenance

• Factor 4 Fatigue recovery

• Factor 5 sleep time

SUS was created based on 10 Things

to Know About the System Usability Scale

@aroma store,@aroma, https://www.at-aroma.com/

store/

BIOSIGNALS 2022 - 15th International Conference on Bio-inspired Systems and Signal Processing

(SUS)(measuringU, 2013). The subjects answered

each item on a 5-point scale. The higher the score,

the higher the evaluation of SUS. The subjects were

asked to answer each item on a 5-point scale. The

higher the score, the higher the assessment of SUS.

At the end of the SUS questionnaire, the subjects

were asked to describe their product impressions.

The following is the scale of the SUS items and

responses.

1. I would like to use this system frequently. (1-not

at all, 2-no, 3-don’t know, 4-yes, 5-very much)

2. It turns out that the system is unnecessarily com-

plicated. (5-easy)

3. I thought it was easy to use. (5-very much)

4. I think you need the support of a technician to use

this system. (5-not at all)

5. It turns out that the various functions of this sys-

tem are well integrated and scattered. (5-very

much)

6. I thought there were too many contradictions in

this system. (5-not at all)

7. I think most people will soon learn how to use this

system. (5-very much)

8. I found this system very difﬁcult to use. (5-not at

all)

9. I was very conﬁdent in using this system.(5-think)

10. Before I started using this system, I needed to

learn a lot. (5-not at all)

5 EXPERIMENTAL RESULTS

5.1 Result of Pulse Interval

Table1 shows the standard deviation of the pulse inter-

val for each time in each experiment. The areas with

a standard deviation of zero are areas with no data.

From the standard deviation, it can be considered

that the standard deviation value of the pulse interval

during napping is smaller than that during free time

in all experiments and that the pulse interval ﬂuctu-

ates less and is calmer. K, the only experiment in

which the standard deviation of the napping time be-

came large, will be discussed later.

When comparing the standard deviations during

napping in the ﬁrst-sleep experiments and ﬁrst-wake

experiments, the standard deviation value in the ﬁrst-

sleep experiment was more petite, suggesting that us-

ing the correct scent resulted in less ﬂuctuation in the

pulse interval and relaxation. However, when com-

paring the ﬁrst-sleep experiment with the no-sleep

experiment, in some cases, the no-sleep experiment

showed less ﬂuctuation in the pulse interval. This will

also be discussed later.

Figure10 shows a Lorenz plot of the pulse inter-

val at the center position every 5 minutes in the ﬁrst-

sleep experiment of subject A. Next, Figure11 shows

a Lorenz plot of the pulse interval at the center posi-

tion every 5 minutes in subject A’s ﬁrst-wake exper-

iment. Finally, Figure12 shows a Lorenz plot of the

pulse interval at the center position every 5 minutes

in Subject A’s no-sleep experiment. If there is a plot

at the upper right of the Lorenz plot, it means that the

subject is relaxed at that timing, and it can be seen

that the subject is relaxed after napping in all experi-

ments. When the positions of the last 55-60 min plots

were compared, the positions were (990.7, 989.1) in

the ﬁrst-sleep experiment, (804, 804.4) in the ﬁrst-

wake experiment, and (742.7, 740.8) in the no-sleep

experiment, indicating that the ﬁrst-sleep experiment

continued to be the most relaxed.

Figure 10: Lorenz plot of subject A’s ﬁrst-sleep experiment.

Figure 11: Lorenz plot of subject A’s ﬁrst-wake experience.

Figure 12: Lorenz plot of subject A’s no-sleep experiment.

AroNap: A Scent-based Nap Promotion System

Table 1: Standard deviation of RRI at the begining, in the middle, and at the end of the nap in each condition (from left to

right: ﬁrst-sleep experiment, ﬁrst-wake experiment, no-sleep experiment).

0-20min 20-40min 40-60min 0-20min 20-40min 40-60min 0-20min 20-40min 40-60min

A 357 281 427 346 299 376 333 292 447

B 377 133 495 - - - 235 102 352

C 326 149 424 247 150 355 261 617 321

D 451 178 462 - - - 447 159 351

E 391 70 440 410 149 428 302 78 441

F 136 88 227 260 106 349 213 95 253

G 389 110 465 369 156 410 390 131 389

H 242 130 357 249 240 355 329 183 394

I 450 174 439 - - - 257 156 365

J 317 112 288 340 208 341 - - -

K 321 145 287 393 408 370 - - -

L 270 99 257 - - - 242 66 208

M 419 125 424 - - - 372 342 397

Table 2: Result of OSA sleep questionnaire (standardized

score).

First sleep First wake up No AroNap

Factor 1 50.89 49.14 45.46

Factor 2 39.86 44.95 37.06

Factor 4 52.95 51.25 48.28

Factor 5 40.59 45.71 41.55

5.2 Result of OSA Sleep Questionnaire

The table 2 is the result of the OSA sleep question-

naire. The numbers in the table are the standardized

scores, and 50 points are the average score.

• Factor 1: drowsiness upon waking, exceeded the

mean score of 50 points only in the ﬁrst sleep ex-

periment, indicating that the correct use of the fra-

grance resulted in a comfortable waking. Com-

paring the results of the experiments with and

without scent, it can be said that sleepiness upon

awakening is more comfortable when the scent is

used, even when it is not used correctly.

• Factor 2: falling asleep and staying asleep, is the

best result of the previous waking experiment.

The questions for factor 2 were ”I was able to

sleep well,” ”I was not in a state of stupor be-

fore falling asleep,” ”I was able to fall asleep eas-

ily,” ”I did not wake up during sleep,” and ”I slept

deeply.” In the ﬁrst-sleep experiment, where the

last 10 minutes of the napping period was the

waking time, the participants felt that they could

have slept a little longer, which is thought to have

made it difﬁcult for them to obtain high scores.

• Factor 4: recovery from fatigue, was higher than

the average score in the experiment with fra-

grance, suggesting that fragrance can provide a

more effective nap.

• Factor 5: sleep duration, the score of the ﬁrst-

sleep experiment was lower than that of the no-

sleep experiment and was the lowest among the

three.

As in Factor 2, the score of the ﬁrst-wake experi-

ment was higher because the participants felt that they

could sleep satisfactorily because they could sleep un-

til just before their nap time. Factors 2 and 5 were

lower than the average scores, indicating that it is dif-

ﬁcult to achieve higher scores than the average during

a 20-minute nap.

From the above results, it can be said that the cor-

rect use of fragrances can suppress sleepiness upon

awaking, recover fatigue, and provide a comfortable

waking. However, even if the fragrance is not used

correctly, it is still possible to wake up comfortably

compared to the case where no fragrance is used. In

addition, the order of the fragrances can be intention-

ally switched depending on the purpose because the

satisfaction with the sleep time increases when the

fragrance for falling asleep is used later.

5.3 SUS Result

Table3 shows the result of SUS evaluation. The score

of each item was the average of the scores of all sub-

jects, and the total value was calculated by the method

of sum of each answer-1 × 2.5. The average score

for AroNap was 84.8 points, which was over 80%.

However, the mean score for the item ”I was conﬁ-

dent in using the system” was particularly low, sug-

gesting that the system was not easy for users to use

at ﬁrst sight. The mean scores for ”I would like to

use this system frequently,” ”I found it easy to use,”

and ”I found the various functions of this system well

integrated” were also low, although they exceeded 4

points, suggesting that the desire to use the system

BIOSIGNALS 2022 - 15th International Conference on Bio-inspired Systems and Signal Processing

Table 3: SUS result (average score).

Question Number Result

1 4.15

2 4.54

3 4.15

4 4.46

5 4.15

6 4.62

7 4.69

8 4.54

9 3.85

10 4.77

Calculation result 84.81

needs to be increased by making it easier to use. On

the other hand, the mean scores for ”I think most peo-

ple will learn how to use this system quickly” and ”I

needed to learn a lot of things before I started using

this system” were high. In particular, the latter score

was 4.8, indicating that AroNap can be used without

any particular knowledge required.

5.4 Comments in the Free Description

Column

We received many opinions on the impression of us-

ing AroNap, which was conducted together with the

SUS questionnaire. Positive feedback included com-

ments such as ”I woke up feeling good” and ”I felt re-

laxed,” as well as words on the system such as ”easy

to use” and ”just the right amount of fragrance.” Neg-

ative comments included ”difﬁcult to change position

as it seems to block the lid of the AroNap,” ”surprised

by the sound of the system,” and ”heavy.” One com-

ment was, ”Instead of the wake-up scent being emit-

ted 10 minutes before, could the wake-up scent be

emitted 3 minutes before?” We will keep these com-

ments in mind for future reference.

6 CONSIDERATION

From the standard deviation of the pulse interval, it

can be considered that in all experiments, the pulse

interval during napping is calmer with less ﬂuctuation

in the pulse interval than the free time. However, in

K of the wake-up experiment, the only experiment in

which the standard deviation of the napping time be-

came large, an incident such as the M5StickC falling

during the experiment occurred, and it is thought that

the standard deviation became prominent due to sur-

prise. In response to the fall of the M5StickC, we took

measures such as taping the M5StickC to the box and

lid, but it turned out that the M5StickC would fall de-

pending on how the AroNap user slept. In addition,

when comparing the ﬁrst-wake experiment with the

no-sleep experiment, it is thought that the pulse inter-

val may have ﬂuctuated due to the surprise caused by

the operating noise of the AroNap system, as the pulse

interval ﬂuctuated less in the no-sleep experiment in

some cases.

From the results of the pulse interval, it was found

that the correct use of AroNap resulted in a state of

calmness and that the state of relaxation lasted for a

long time. The questionnaire results indicate that the

introduction of sleep by fragrance is practical for a

good sleep in terms of sleepiness upon waking and the

degree of recovery from fatigue. However, only a few

subjects took a nap, and it was difﬁcult to fall asleep

within 20 minutes. From the Lorenz plot, the subjects

were relaxed regardless of the presence or absence of

sleep, and the subjects were relaxed because the plot

position after napping was in the upper right corner of

the graph. Even if it is difﬁcult to sleep, it is possible

to improve work efﬁciency by relaxing the body and

mind so that AroNap can improve work efﬁciency.

7 CONCLUSION

In this study, we developed ”AroNap,” which uses fra-

grances to assist in falling asleep and waking up for

short naps. As a result of evaluation experiments, it

was conﬁrmed that the correct use of the scent had a

long-lasting, relaxing effect. In addition, the reduc-

tion of drowsiness and recovery from fatigue upon

waking was conﬁrmed, indicating that it is possible

to take a good nap. As a whole, we received the opin-

ion that the scent makes us feel relaxed and easy to

sleep. However, some people believe that the sys-

tem is heavy and the operating noise is anxious, and

there are some parts where such a reaction appears

in the results of the measured pulse interval. In the

future, while collecting opinions and data from more

test subjects, we would like to improve the fact that

AroNap restricts the sleeping position, the operating

noise, and the weight. AroNap is expected to be used

to improve work efﬁciency even if it does not lead to

napping, but we would like to enhance its functions

as a system that can introduce napping.

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BIOSIGNALS 2022 - 15th International Conference on Bio-inspired Systems and Signal Processing