Analysis of Human Autonomic Nervous Activity Based on Big Data Measurement
Via SmartPhone
Makoto KOMAZAWA
Graduate School of System Informatics, Kobe
University
Rokkodai-cho, Nada-ku, Kobe 657-8501 Japan
makoto.komazawa@winfrontier.com
Kenichi ITAO
WINFrontier Co., Ltd.
247 Shin-Yurakucho Building, 1-12-1 Yurakucho,
Chiyoda-ku, Tokyo, 100-0006 Japan

Abstract—This study used a large amount of autonomic
nervous system data to investigate the relationship between
autonomic nervous system and activity, day of the week, andregion. Data was measured via a heart rate variability analysis
system that utilizes the camera of smartphones [8]. This system
was developed by the authors during previous research. As foras the relationship between autonomic nervous system andactivity, total power and sympathetic nervous activity were
found to rise after waking, while during leisure time, it was
found that total power rises and sympathetic nervous activity
is inhibited. Concerning the relationship between autonomic
nervous system and day of the week, it was found that total
power decreases from the middle through the latter part of theweek (namely, Wednesday, Thursday, and Friday), while itrises on Saturday. What’s more, sympathetic nervous activity
is suppressed on Saturday. Regarding the relationship between
autonomic nervous system and region, it was found that total
power is lower in the Kanto region than in others. Regarding
weather conditions, the results showed a trend in which asignificant decrease was seen in sympathetic nervous activity
the higher the temperature. In addition, a significant increase
was seen in the sympathetic nervous system the higher theatmospheric pressure. Lastly, a significant decrease was seen in
the sympathetic nervous system the more precipitation therewas. These results accord with prior research and with humanbiological phenomena, and we were able to use big data tostatistically demonstrate our hypothesis.
Keywords-Heart rate variability; Autonomic nervous system;
Big Data Measurement; Activity; Day of the Week; Region;
Wether ConditonsI.

INTRODUCTION

It has long been recognized that modern society is stressful.
If human beings are subjected to stress for a long period, thefunctions of autonomic nervous system and the endocrine
system, that controls the adrenocortical hormone, will be
seriously influenced [1]. The autonomic nervous system
controls the balance between the sympathetic nerve activity,
which responses for maintaining the tension and excitement,
and the parasympathetic nerve activity, which responses for

Hiroyuki KOBAYASHIJUNTENDO University
2-1-1 , Hongou, Bunkyou-ku, Tokyo, 113 – 8421 ,Japan

Zhiwei LUO
Organization of Advanced Science and Technology
Kobe University
Nada-ku, Kobe 657-8501 Japan

maintaining relaxation. Therefore, it is very important for
self-management to routinely recognize the state of ourautonomic nervous system during everyday life [2].
The typical non-invasive technique for measuring
autonomic nervous system uses a small, specialized heart
rate sensor [3], or a fingertip pulse wave sensor [4]. These
devices are used to measure RR interval (heartbeat interval)
and peak interval (a value corresponding to the RR intervalthat is detected from the pulse waveform) [5], whereupon
heart rate variability analysis is performed to calculate
sympathetic nervous and parasympathetic nervous activity
indicators [6]. These systems use Fast Fourier Transform(FFT) [7] to calculate the autonomic nervous activity from
RR interval data in one to five minutes.
However, all these products use extremely expensive,
specialized sensors and systems to measure RR intervals andpulse wave peak intervals. Thus, the hurdles to their use by
the general public are high. Because of this, measurement ofautonomic nervous system conditions has been limited to
specialized facilities such as hospitals.
During previous research, authors developed a simple andprecise measurement system that does not rely on specialized
devices, but utilizes the camera of smartphones sold on thegeneral market [8]. In this system, the device camera isplaced on the tip of the finger for a short amount of time (justover 30 seconds), where it detects the pulse waveform peakinterval from luminance changes in blood flow. Then, heart
rate variability analysis is performed to measure the detailed
conditions of the autonomic nervous system, namely, itsbalance and amount of activity (total power).
This system is currently being put to use by approximately
1,000,000 users (as of March 2016)[9] as an App for theiriPhone (Apple Inc.)[10] or Android device (Google Inc.)[11].
Up to this point, autonomic nervous system measurements
have been mainly conducted at hospitals, laboratories, andother facilities, using specialized sensors and equipment.
Thus, the number of possible measurement subjects waslimited to few hundred people at most. And as measurements
were conducted under a particular set of circumstances, theycannot be considered an accurate representation ofautonomic nervous system in daily life.

The system utilized in this study, however, is able to easily
measure large amount of data at any time, any location, andafter any activity, giving researchers an understanding ofautonomic nervous system conditions under everyday
circumstances.
The authors used this system in previous research toinvestigate the relationship between autonomic nervous
system and age and BMI, based on approximately 100,000
entries of autonomic nervous system data. This study foundthat the autonomic nervous activity decreases significantly as
age and BMI increases [12]. The authors also published astudy on the diurnal variation of autonomic nervous system,
based on approximately 100,000 entries of autonomic
nervous system data [13]. The results of these studies are
consistent with results obtained using specialized sensors andmeasurement equipment. While there is a comparatively
high volume of research [14] [15] on the correlation between
atmospheric temperature (one aspect of weather) andchanges in the human body, there remains little research into
other factors like atmospheric pressure and precipitation.
Studies on all of these factors have involved small samples
sizes, so there was as yet no research that utilized a big data
set of several hundreds of thousands of entries to analyze therelationship of weather to the autonomic nervous system.
This research uses big data on the autonomic nervous
system and analyzes it according to the six parameters below.












The relationship between autonomic nervous system
and activity
The relationship between autonomic nervous systemand day of the week
The relationship between autonomic nervous system
and region
The relationship between autonomic nervous system
and atmospheric temperature
The relationship between autonomic nervous system
and atmospheric pressure
The relationship between autonomic nervous systemand precipitationII.

METHODSThis study used a heart rate variability analysis systemutilizing the camera of smartphones [8]. In this system, thesmartphone camera is placed against the tip of the finger,
where it continuously acquires data on the luminance of theskin. A pulse wave is derived from the changes in luminance,
and the peak interval (corresponds to the RR interval) is
detected from that pulse waveform. Then, frequency analysis
is performed on peak interval fluctuations to calculate theautonomic nervous system indicator. This system is outlinedin Figure 1.
The frequency analysis conformed to the proceduredescribed in [6], with the low frequency component (LF)
calculated as 0.04 Hz–0.15 Hz, and the high frequency
component (HF) calculated as 0.15 Hz–0.4 Hz.
LF/HF values are used as indicators of sympathetic nervous
activity, as well as indicators of tension, stimulation, andstress [6].The sum of the LF and HF values are called thetotal power (TP), and it serves as an indicator of theautonomic nervous activity [6]. The total power is said to becorrelated with fatigue, with smaller values indicating higher
levels of fatigue [16].

Figure 1. System Outline

This paper analyzes the autonomic nervous system data of
27,307 subjects, 130,648 data about behavior, daily andreginal changes and analyzes the autonomic nervous systemdata of 53,800 subjects, 241,185 data about weather
conditions.
Measurement data was used with the consent of the subjects,
in accordance with the ethics regulations of WIN FrontierCo., Ltd.
IBM SPSS Statics Version 22 was used for this study’s
statistical processing. The significance level was set to 5%.
III.

THE RELATIONSHIP BETWEEN AUTONOMICNERVOUS SYSTEM AND ACTIVITY

In this section, a relationship (under everyday
circumstances) between autonomic nervous system andactivity is shown. In the research conducted up to this point,
there have been few reports analyzing trends (based on alarge amount of data) in autonomic nervous system fordifferent activities of everyday life.
A. The Relationship between Total Power and Activity
In this section, the relationship between total power andactivity is investigated. It is said that performing logarithmictransformation on total power (an indicator of autonomic
nervous system) increases its normality [17], so logarithmictransformation was performed on the total power values(LnTP) for all the measurement data. The resulting values
were then divided into eight groups based on activity, andthe differences between groups were investigated by
performing a Games-Howell multiple comparison procedure.
The results are given in Figure 2. Total power was found tobe significantly higher after waking and during leisure time,a trend that was also observed when analyzing data
separately by sex.
It has been observed in previous research that the amount ofautonomic nervous system rises before and after waking due
to diurnal variation in autonomic nervous system [18], atrend that is consistent with observations made in this study.
What’s more, total power was found to rise during leisuretime, suggesting that leisure is effective in increasing
autonomic nervous system and function. Conversely, total
power was found to be low during housework.

Figure 2. The Relationship between LnTP and Activity

B. The Relationship between LF/HF and Activity
In this section, the relationship between LF/HF (anindicator of sympathetic nervous activity) and region isinvestigated. It is said that performing logarithmictransformation on LF/HF increases its normality [17], so
logarithmic transformation was performed on the LF/HF
values (LnLF/HF) for all the measurement data. A GamesHowell multiple comparison procedure was then performedon these values, the results of which are given in Figure 3.
Sympathetic nervous activity was found to rise significantly
after waking and during work, while during leisure time, it
was found that sympathetic nervous activity is inhibited.
These trends were also observed when analyzing data
separately by sex.
It has been observed in previous research that sympathetic
nervous activity rises before and after waking [18], a trendthat is consistent with observations made in this study.
It was also observed that during leisure time, sympathetic
nervous activity is inhibited and subjects are relaxed.

there have been few reports analyzing trends (based on alarge amount of data) in autonomic nervous system (under
everyday circumstances) for different days of the week.
A. The Relationship between Total Power and Day of the
Week
In this section, the relationship between total power and dayof the week is investigated. .
Data was divided into seven groups based on day of theweek, and the differences between groups were analyzed by
performing logarithmic transformation on the TP values(LnTP) for all the measurement data, and then performing a
Games-Howell multiple comparison procedure. The results
are given in Figure 4.
Total power was found to significantly decrease from the
middle through the latter part of the week (namely,
Wednesday, Thursday, and Friday), while it significantly
increases on Saturday. These trends were also observed
when analyzing data separately by sex.
While there is believed to be some dispersion based onregion and workplace, according to information reported by
the Ministry of Health, Labour, and Welfare on industrial
accident occurrence by day of the week [19], accumulating
fatigue, decreasing concentration, and other factors
contribute to a high incidence of industrial accidents aroundThursday (with the weekend approaching). In the report, thework week starts on Monday.
Most people have likely experienced increasing fatigue
from the middle through the latter part of the week, a trendthat is consistent with the current study’s finding that total
power decreases during the same period of the week.

Figure 4. The Relationship between LnTP and Day of the Week

Figure 3. The Relationship between LnLF/HF and Activity

IV. THE RELATIONSHIP BETWEEN AUTONOMICNERVOUS SYSTEM AND DAY OF THE WEEKIn this section, a relationship (under everyday
circumstances) between autonomic nervous system andactivity is shown. In the research conducted up to this point,

B. The Relationship between LF/HF and Day of the Week
In this section, the relationship between LF/HF (anindicator of sympathetic nervous activity) and day of theweek is investigated. Logarithmic transformation was
performed on the LF/HF values (LnLF/HF) for all themeasurement data, and then a Games-Howell multiple
comparison procedure was performed. The results are given
in Figure 5. Sympathetic nervous activity was found to
decrease significantly on Saturday, a trend that was also
observed when analyzing data separately by sex. As
mentioned previously, total power was found to be high on

Saturday. It can be said that, compared to other days of theweek, autonomic nervous system is extremely good on
Saturday.
This may be influenced by the cycle of the days of the week.
the sympathetic nervous activity of many people increases
during weekdays as they are kept busy with work,
housework, and other duties, and this increase is seen again
on Sunday as peoples’ tension and emotions rise in
anticipation of the coming week.

Figure 6. The Relationship between LnTP and Region

B. The Relationship between LF/HF and Region
In this section, the relationship between LF/HF and region
is investigated. Logarithmic transformation was performedon the LF/HF values (LnLF/HF) for all the measurement
data, and then a Games-Howell multiple comparison
procedure was performed. The results are given in Figure 7.
No significant difference in LF/HF was observed between
regions.

Figure 5. The Relationship between LnLF/HF and Day of the Week

V.

THE RELATIONSHIP BETWEEN AUTONOMICNERVOUS SYSTEM AND REGION

In this section, a relationship (under everyday
circumstances) between autonomic nervous system andregion is shown. In the research conducted up to this point,
there have been few reports analyzing regional trends (basedon a large amount of data) in autonomic nervous system
under everyday circumstances.
A. The Relationship between Total Power and Regions
In this section, the relationship between total power andregion is investigated. Data was divided into eight groups
based on prefecture, and the differences between groups
were analyzed by performing logarithmic transformation on
the TP values (LnTP) for all the measurement data, and thenperforming a Games-Howell multiple comparison procedure.
The results are given in Figure 6. The total power of the
Kanto region was found to be significantly lower than inother regions, a trend that was also observed when analyzing
data separately by sex. In general, the incidence ofautonomic neuropathy is said to be higher in the capital (with
its higher stress levels) than in the provinces. This may becorrelated with the results of this study.

Figure 7. The Relationship between LnLF/HF and Region

VI.

THE RELATIONSIP BETWEEN AUTONOMICNERVOUS SYSTEM AND ATMOSPHERICTEMPERATURE

In this section, we surveys the relationship of atmosphericpressure to autonomic nervous system. Data on atmospherictemperature averages was downloaded from the Japan
Meteorological Agency's website [20] and the date ofmeasurements and data from each prefecture tied tomeasured values by city as grouped by ordinance-designatedcity. The temperature intervals were grouped around days
measuring 25 degrees Celsius, or what is called a "summer'sday" [21], with categories for days below 25 degrees andabove 25 degrees, respectively.
It has been reported that treating LF/HF, an index of
sympathetic nervous activity, as a logarithm normalizes data[17], so LF/HF for each data entry was converted to the
LnLF/HF logarithm, and the difference in population mean
between each was analyzed. Results are seen in Figure 8.

Figure 8. The Relationship between LnLF/HF and Atmospheric
Temperature

The results show a trend in which there is a significant drop
in sympathetic nervous activity the higher the temperature is(P value: < statistical significance 0.05)．
In general, it is understood that in cold weather, the effectsof the sympathetic nervous system constrict the bloodvessels and prevent the body from dispersing heat; in warm
weather, the parasympathetic nervous system expands the
blood vessels and causes the body to perspire, thereby
decreasingbodytemperature.[22]This
research
hypothesized that a similar biological phenomenon would bepresent in the autonomic nervous system and manifest
similar heat- and cold-prevention mechanisms. We were able
to utilize a large set of 200,000 entries of data to statisticallydemonstrate this.
We believe this represents an extremely useful set ofreference data that can be used for adjusting day-to-day
lifestyles to account for temperature increases, to control
health, et cetera.
VII. THE RELATIONSIP BETWEEN AUTONOMICNERVOUS SYSTEM AND ATMOSPHERIC PRESSURE
In this section, we examine the relationship between
atmospheric pressure and the autonomic nervous system.
Data on atmospheric pressure averages was downloaded
from the Japan Meteorological Agency's website [20] andthe date of measurements and data from each prefecture tied
to measured values by city as grouped by ordinancedesignated city. The pressure intervals were grouped aroundreadings of 1013hPa for one unit of pressure, with categories
for days below 1013Hpa and above 1013Hpa, respectively.
LF/HF for each entry was converted to the LnLF/HF
logarithm, and the difference in population mean between
each was analyzed. Results are seen in Figure 9.

one feels depressed [23] [24]; in high pressure systems
associated with fair weather, there is increased sympathetic
nervous activity, with exacerbated release of dopamine in the
corpus striatum, exacerbated release of peripheral
catecholamine, et cetera, causing one to feel comfortable andat ease. [23] [25] In this way, this research shows similar
trends to those found in prior research, and we were able tosuccessfully use the data set of approximately 200,000
entries to statistically demonstrate this autonomic nervous
system function. We believe this represents an extremely
useful set of reference data that can be used for adjusting
day-to-day lifestyles to account for atmospheric pressurechanges, to control health, et cetera.
VIII. THE RELATIONSIP BETWEEN AUTONOMICNERVOUS SYSTEM AND PRECIPITATIONIn this section, we examine the relationship between
precipitation and the autonomic nervous system. Data on
atmospheric pressure averages was downloaded from theJapan Meteorological Agency's website [20] and the date ofmeasurements and data from each prefecture tied tomeasured values by city as grouped by ordinance-designatedcity.
The precipitation intervals were grouped around 10mm ofprecipitation in a 24-hour period, with categories for days
below 10mm and above 10mm, respectively.
LF/HF for each entry was converted to the LnLF/HF
algorithm, and the difference in population mean between
each was analyzed. Results are seen in Figure 10.
The results show a trend in which there is a significant
increase in sympathetic nervous activity the more rain thereis. (P value < statistical significance 0.05).
In general, it is understood that on days with fair weather,
there is more oxygen in the atmosphere, and this increases
oxygen pressure in the bloodstream, causing the body toprioritize sympathetic nervous activity; by contrast, on
cloudy days with poor weather, there is less oxygen, and thisdecreases oxygen pressure in the bloodstream, causing the
body to prioritize parasympathetic nervous activity. [23] [24][25]. This research hypothesized that a similar biologicalphenomenon would be present in the autonomic nervous
system. We believe this represents an extremely useful setof reference data that can be used for adjusting day-to-day
lifestyles to account for precipitation changes, to control
health, et cetera.

Figure 9. The Relationship between LnLF/HF and Atmospheric Pressure

The results show a trend in which there is a significant
increase in sympathetic nervous activity the higher thepressure is (P value < statistical significance 0.0.5)
According to prior research, low pressure systems
associatedwithweatherirregularity
increaseparasympathetic nervous activity, such as in bradycardia,
decreased granulocytes, increased lymphocytes, decreased
urinary adrenaline, et cetera. The body becomes sluggish andFigure 10. The Relationship between LnLF/HF and Precipitation

IX.

CONCLUSION

This study used a large amount of autonomic nervous
system data
to investigate the relationship between
autonomic nervous system and activity, day of the week, andregion. Data was measured via a heart rate variability
analysis system that utilizes the camera of smartphones [8].
This system was developed by the authors during previous
research. As for as the relationship between autonomic
nervous system and activity, total power and sympathetic
nervous activity were found to rise after waking, whileduring leisure time, it was found that total power rises andsympathetic nervous activity is inhibited.
Concerning the relationship between autonomic nervous
system and day of the week, it was found that total power
decreases from the middle through the latter part of the week
(namely, Wednesday, Thursday, and Friday), while it rises
on Saturday. What’s more, sympathetic nervous activity issuppressed on Saturday. Regarding the relationship between
autonomic nervous system and region, it was found that total
power is lower in the Kanto region than in others.
Regarding weather conditions, the results showed a trend inwhich a significant decrease was seen in sympathetic
nervous activity the higher the temperature. In addition, asignificant increase was seen in the sympathetic nervous
system the higher the atmospheric pressure. Lastly, asignificant decrease was seen in the sympathetic nervous
system the more precipitation there was. These results accord
with prior research and with human biological phenomena,
and we were able to use big data to statistically demonstrate
our hypothesis.
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