Journal of Heat Island Institute International Vol. 12-2 (2017)

Academic Article

Measurement of physiological responses ofwalking and standing pedestrians
exposed to changeable thermal environment in outdoor space
1

Takuma Hasegawa*2

Yasuyuki Ishida*

3

Saori Yumino*

2

Tomonobu Goto*

2

Akashi Mochida**1 Engineer for Building Equipments, Takenaka Corporation* Dept. of Architecture and Building Science, Graduate School of Engineering, Tohoku University*3 Technical Research Institute, Kajima Corporation
2

Corresponding author: Yasuyuki ISHIDA, y.ishida@sabine.pln.archi.tohoku.ac.jp
ABSTRACTIn recent years, health hazards during extremely hot summer conditions have increased rapidly with urban
heat islands, severe weather, etc. Previous studies have employed thermal comfort or thermal stress indices, such as
SET*, PET, WBGT, etc., to assess outdoor thermal environment, and the health hazard risk is considered to be very
high at the points where such indices are higher than the threshold values. However, people in outdoor spaces often
walk in real-life situations on urban streets, and do not stay in the same place for prolonged periods of time. Thus,
even when there are extremely hot points in the evaluation area, the health risk may not be high if there are alsocool spots nearby. This study simultaneously measured outdoor thermal environments and human physiologicalresponses to determine the effects of changeable environments (e.g, wind velocity and radiation) on pedestrians
walking and standing in outdoor spaces.
Field measurements were performed in pedestrian spaces within the premises of Tohoku University from
September 26-30, 2014. The subject wore clothes with instruments attached to measure physiological variables(skin surface temperature, core temperature, heat flux at skin surface and blood pressure) and they walked with acart with attached instruments for meteorological variables (air temperature, relative humidity, globe temperature,
wind velocity, and short- and long-wave radiation). In this study, five sets of measurements were carried out toevaluate the influence of four characteristics of the outdoor environment that are not usually found in indoor
environments:(1) wide ranges of wind velocity,(2) wide ranges of radiation,(3) sudden change in the surrounding environment (mostly due to moving to other places) and(4) physiological changes induced by walking.
The results obtained from these measurements were as follows.
(1) When mean wind velocity changed from approx. 0 m/s to 1.4 m/s, skin temperature decreased gradually.
(2) When MRT changed from 20°C to 75°C, skin temperature increased rapidly even though mean wind velocity
was 1.2 m/s.
(3) When environmental condition, especially MRT, changed suddenly, skin temperatures varied greatly at the bodyparts covered without any clothes.
(4) Skin temperature during walking was lower than that during standing.
Key Words : Walking pedestrians, Moving measurements of outdoor thermal environment, Human physiological responses

1. Introduction

weather, etc. Previous studies employed thermal comfort orthermal stress indices, such as SET*(1), PET(2)-(4), WBGT(5), etc.

In recent years, health hazards in extremely hot summer

to assess the outdoor thermal environment(6)-(10), and the healthconditions have increased rapidly with urban heat islands, severe

hazard risk is considered to be very high at the points where- 46 -

such indices are higher than the threshold values. However,determine the effects of changeable environment factors in

people in outdoor spaces are often walking on urban streets, andoutdoor spaces (e.g, wide ranges of wind velocity and radiation)

they do not stay at the same point for a long time.

on pedestrians.

Thus, even though there are very hot points in the evaluationarea, health risks are not high if there are cool spots nearby. For

2.

Field

measurementsofoutdoorthis study, simultaneous measurements were performed ofenvironment and pysiological responses

thermaloutdoor thermal environments and physiological responses ofpedestrians walking and standing in outdoor spaces in order toArea B(Building shade)

Point B
(Building shade)

CP 2
CP 6

CP 5

Course

CP 7

CP 3
CP 1

Area A(Sunny space)

Point A
(Sunny space)

CP 4※ CP : Check Point(1) Each Area or Point name(2) Course for Case 5
Fig. 1: Measurement Areas.

Table 1: Schedules and Factors Considered in Each Case.
Schedule

Factors Considered

Case1

Remain standing at Point B (Building shade, Fig. 1 (1)) for 30 min.

Case2

Remain standing at Point A (Sunny space, Fig. 1 (1)) for 30 min.

Case3

Case4

Case5

Moving from Point A to Point B and Point B to Point A (Fig. 1 (1)),
and remain standing for 10 min. at each point.
Moving from Area A to Area B and Area B to Area A (Fig. 1 (1)),
and remain walking for 10 min. in each area.
Walking along Course (Fig. 1 (2)).

Wide ranges of wind velocity+ Wide ranges of radiation
Wide ranges of wind velocity,
Wide ranges of radiation+ Rapid chang of surrounding environment
Wide ranges of wind velocity,
Wide ranges of radiation,
Rapid chang of surrounding environment,+ WalkingWalking along real outdoor space

Move toPoint A or Point B: measure blood pressure and heat rate

Seated in room with
controlled factors

30 min.

Wide ranges of wind velocity

Remain standing at Point A or Point B

30 min.

Start

End

(1) Cases 1 and 2
Move toPoint A or Area A
Seated in room with
controlled factors

30 min.

Move toPoint B or Area B

Move toPoint A or Area A

Remain standing at Point A
or remain walking in Area A

Remain standing at Point Bor remain walking in Area B

Remain standing at Point A
or remain walking in Area A

10 min.

10 min.

10 min.

Start

End

(2) Cases 3 and 4
Move to Course
CP 1
Seated in room with
controlled factors

30 min.

CP 2

CP 3

CP 4

CP 5

CP 6

CP 7

Walking along Course

about 40 min.

Start(3) Case 5
Fig. 2: Case Schedules.

- 47 -

EndTable 2: Measured Meteorological and Physiological Variables and Instruments Used.
Variables

Interval

HeightWind direction, wind velocity

3D ultrasonic anemometer (R.M. Young, CYG-81000)

Instruments

0.1 s

1.8 m

Air temperature, relative humidity

Thermistor/polymer sensors (T&D,TR-72U) with double blower pipe and sun shield

1s

1.0 m

Globe temperature

Globe ball with thermocouple

1s

1.5 m

Short- and long-wave radiation

Net radiometer (EKO, MR-60)

1s

1.0 m

Skin temperature

Thermocouple (forehead, belly, lower arm, back of the hand, thigh, calf and instep)

1s

Core temperature (tympanic temperature)

Thermopile and thermistor (TECHNO SCIENCE, BL-100)

1s

Heat flux (lower arm)

Heat flux sensor (CAPTEC, HF-D30)

1s

Blood pressure (upper arm), heart rate

Blood pressure monitor (A&D, TM-2431)

Evaporated sweat

Digital weight scale (A&D, GP-100K)

Positional information

Mobile phone

Wind direction,
Wind velocity

Core temperature(Tympanic temperature)

Globe temperature

Blood pressure, Heart rate

Short- and Long-wave
radiation (3D)Heat flux

Temperature,
Relative humidity

Skin temperature(forehead, belly, lower arm,back of the hand, thigh, calf,
instep)Z

XY(1) Cart for measurement of meteorological variables(2) Clothing for measurement of physiological variables

Fig. 3: Cart and Clothing with Attached Instruments.
2.1

Case Settings

2.2

Measured Variables

Field measurements were carried out in the open space within

The measured variables are shown in Table 2. A cart withthe premises of Tohoku University from September 26-30, 2014.

attached instruments was used to measure meteorological

The measurement areas are shown in Fig. 1. The measurement

variables, including relative wind direction and relative wind

start times were 12:35 on 26th in Case 1, 10:40 on 26th in Case

velocity (absolute value of the difference between the wind

2, 10:35 on 28th in Case 3, 12:35 on 28th in Case 4 andvelocity in the area and the moving velocity of the cart),

10:33 on 30th in Case 5, respectively.

temperature, relative humidity, short-wave radiation andIn this study, four factors were identified that affect human

long-wave radiation, and globe temperature. Three net

physiological responses in outdoor spaces:(1) wide ranges ofradiometers were used to measure three-dimensional (3D)

wind velocity, (2) wide ranges of radiation, (3) rapid changes inradiant heat transports. This enabled us to evaluate short- andthe surrounding environment (mainly caused by moving to otherlong-wave radiant heat fluxes from the front, back, right, left,

places) and (4) walking. Five types of measurements weretop, and bottom.

performed to determine how these factors affected pedestrians.

Clothing with attached instruments was used to measure

The schedules and factors considered in each case are shown inphysiological variables, including skin temperature, core

Table1 and Fig. 2. In Cases 1 to 4, the factors considered weretemperature (tympanic temperature), heat flux at the skin surface

added one at a time in order to assess human physiologicalof the arm, blood pressure, and heart rate. Heat resistance value

responses to each factor, while the physiological responses ofby clothes was 0.65 clo. Blood pressure and heart rate werepedestrians walking in real outdoor space were measured inmeasured as follows (Table 1): every five minutes for Cases 1

Case 5. In Case 2 and Case 3, the subject stood at Point A withand 2, just after (and before) leaving area, five minutes before

the front of the body facing in the direction of the sun. Subject

leaving the area in Cases 3 and 4, and when the subject reachedremained sitting for 30 min in a controlled room in Building B,

each check point (CP 1~7 in Fig. 1) in Case 5. The subject

where air temperature was 24 °C, relative humidity was 42 %,remained standing for approximately one minute while

indoor airflow velocity was approximately 0 m/s, mean radiantmeasuring blood pressure and heart rate even in Cases 4 and 5.

temperature (MRT) was 24 °C and all the meteorological factors

The cart and clothing are shown in Fig. 3. Weight was measured

were held constant, before each measurement.

at the beginning and end of each measurement and evaporated- 48 -

sweat was assumed to be their difference. Positional informationfrom 20 °C in the room to 75 °C, the skin temperatures increased

was measured using a global positioning system (GPS) with arapidly even though mean wind velocity was 1.2 m/s. Especially,

mobile phone and the walking speed was kept 1.1 m/s in Case 4

the amount of rise in temperatures of forehead and back of theand Case 5.

hand were large. These results show that the skin temperature

Fig. 3 (2) shows a subject in this measurement. The subject was

fluctuation was large at the parts not covered with clothinga man with age 23, height 1.78 m and weight 60 kg.

where thermal resistance by clothes was low or zero.

SET* at each time was calculated by using mean skin

Blood pressure showed little change, and the values in Case 1

temperature and core temperature computed from iterativeand Case 2 were almost the same, as shown in Fig. 4 (10). Fig. 4

calculation by 2-node model(1) using measured air temperature,(11) shows that heart rate in Case 2 was consistently higher thanrelative humidity, wind velocity and MRT at each time as input

Case 1. It is inferred that heart rate increased to increase blood

data. This method was developed by Nakamura et al.(11)flow due to heat release from the body.

3. Results of Field Measurement

3.3

Case 3 (Alternately standing in sunny space andbuilding shade)
3.1

Case 1 (Standing in building shade)

Results of Cases 3 and 4 are shown in Fig. 5. Skin temperatures

Fig. 4 (6) shows the time variations of skin temperatures ofincreased in sunny spaces and decreased in building shade, as

various parts of body in Case 1. When mean wind velocity

shown in Figs. 5 (6), (7) and (8). Similarly to the results ofchanged from approx. 0 m/s in the controlled room to 1.4 m/s,

Case2 mentioned in Section 3.2, a clear relationship was

the skin temperatures of all parts decreased as time proceeded,

observed between the skin temperature and thermal resistance by

although the rate of change was diverse. Fig. 4 (9) shows theclothes.

heat flux at skin surface in Cases 1 and 2. Here, the positive signmeans the heat flux incoming to the skin surface. The heat flux

3.4

outgoing from the skin surface moderately decreased between 5building shade)and 30 minutes after measurement started in Case1. It is

Skin temperatures increased in sunny spaces and decreased inprobably because the convective heat transfer was suppressed bybuilding shade, as shown in Figs. 5 (7) and (8). However, thethe decrease in skin temperature.

range of the increase in Case 4 (walking) was smaller than that

Mean skin surface temperature was calculated from seven skinof Case 3 (standing) for the following reasons: latent heat releasesurface temperatures (the forehead, the belly, the lower arm, theby evaporation of sweat and partial increase of relative windback of the hand, the thigh, the calf and the instep) by weighted

velocity from the arms and legs while walking. In Case 4, theaveraging based on the seven-point method developed by Hardy

metabolic rate and the relative wind velocity were higher than(12)

and DuBois.

Case 4 (Alternately walking in sunny spaces andthose in Case 3, therefore, there was no obvious difference in

Fig.4 (8) shows that mean skin temperatures decreased gradually

SET* between the two cases. Fig. 5 (9) shows that heat flux inin building shade in Case 1. In the controlled room environment,

sunny spaces also changed intricately in Case 4. It is inferred

meteorological variables were almost equal to those measured atthat heat flux was positive because the heat flow plate attached

Point B except the wind velocity, and mean skin temperature

to the left lower arm was exposed to solar radiation when thewas kept constant; therefore, we concluded that the decrease insubject walked from east to west, while that flux became

the skin temperature was caused by the wide ranges of wind

negative because the left arm fell into the shadow of body whenvelocity in the outdoor space.

the subject walked from west to east. Moreover, the absolute

3.2

to west was smaller than that in Case 3. This is considered partly

value of heat flux in Case 4 when the subject walked from east
Case 2 (Standing in a sunny space)

Figs. 4 (1),(2),(3) and (4) show that the meteorological variables

due to increase in convective heat transfer by arm swinging

in Case 2 were almost the same as those measured in Case 1,

while walking.

except MRT. The tendency of the time variation of SET* wasFig. 5 (10) shows that blood pressure in Case 3 and Case 4 weresimilar to that of MRT, as shown in Figs. 4 (4) and (5). Figs. 4

almost the same and constant. The tendency that the heart rate in(4),(7),(8) and (9) show that heat flux became positive (surface

sunny space became higher than that in the building shade wasof the skin gained heat) and skin temperatures increased in Casethe same in both Case 3 and Case 4, although the value of Case

2 when MRT was high; 0-8 and 18-24 minutes after

4 was overall lower than that of Case 3, as shown in Fig. 5 (11).

measurement started.

Under this experimental condition, no increase in heart rate

Fig. 4 (7) presents that the tendency of each skin tempareturecaused by an increase in metabolic rate was measured.

change varied depending on the body part. When MRT changed- 49 -

(1) Air temperature(2) Relative humidity
MRT was high(3) Relative wind velocity(4) MRT

MRT was high38
36

forehead
#REF!
belly
#REF!
instepback of hand
#REF!
#REF!
thigh
#REF!
#REF!

lower arm
#REF!
calf

Skin temperatures [°C]

Skin temperatures [°C](5) SET*
40

34
32

30
28
26

0

5

10

15

20

time [min]

25
25

30
30

35
35

40
40

40

38

Case 2

0

5

10

32
30
28

26

25

30

MRT was high035Case 1

70
MRT was high15

20

time [min]

25

35

40

30

35

40

30

35

40

MRT was high

0

5

10

15

20

time [min]25(9) Heat flux at skin surface

90

10

30

Case 2-200

Case 2

5

25

0

85

110

0

20

-100
-300

40

130

50

15

time [min]100Heart rate[/min]

Blood pressure [mmHg]

Case 110200(8) Mean skin temperature
1505(7) Skin temperatures of Case 2

MRT was high15
20
time [min]lower arm
calf

34

300

Heat flux [W/m2]

Mean skin temperatures [°C]

Case 1back of hand
thigh

36

(6) Skin temperatures of Case 1
40
38
36
34
32
30
28
26

foreheadbelly
instep3035(10) Systolic blood pressure and diastolic blood pressure

Case 2

MRT was high

75
70
65
60
55

40

Case 1

80

0

5

10

15
20
time [min]25(11) Heart rate

Fig. 4: Results of Case 1 (standing in building shade) and Case 2 (standing in a sunny space).

- 50 -

sunny spacebuilding shadesunny spacesunny space(1) Air temperaturesunny spacebuilding shadebuilding shadesunny space(2) Relative humidity

sunny spacesunny space(3) Relative wind velocity
sunny spacebuilding shadebuilding shadesunny space(4) MRT

sunny space

38

back of handthighlower arm
calf

Skin temperatures [°C]

Skin temperatures [°C](5) SET*
foreheadbelly
instep

40

36
34
32

30
28
26

sunny space

05

building shade

10

15

20

time [min]sunny space

25

30

35

40

38

Case 3

32

30
28
26

building shadesunny space

36

34
32

30
28
26

0

5

10

15

20

time [min]25

30

sunny space

0

35

90
70
5

10

15

20

time [min]sunny space

25

Case 3

40

35

40

35

40

Case 4sunny space

05

building shade

10

30

35

15

20

time [min]sunny space

25

30

Case 4sunny spacebuilding shade

70
65
60
0

5

10

15

20

time [min](11) Heart rate

Results of Case 3 (alternately standing in sunny spaces and building shade) andCase 4 (alternately waking in sunny spaces and building shade).

- 51 -

sunny space

75

55

40

Case 380(10) Systolic blood pressure and diastolic blood pressure
Fig. 5:35(9) Heat flux at skin surface

110

0

30

-200

85

building shade

time [min]sunny space

25

0Case 4sunny space

20

-100

-300

40

130

50

15

100

Heart rate[/min]

Blood pressure [mmHg]

Case 3

building shade

10

200

(8) Mean skin temperature
1505(7) Skin temperatures of Case 4

Case 4sunny spacelower arm
calf

34

300

Heat flux [W/m2]

Mean skin temperatures [°C]38back of hand
thigh

36

(6) Skin temperatures of Case 3
40

foreheadbelly
instep40

2530

(1) Air temperature(2) Relative humidity(3) Relative wind velocity(4) MRT

foreheadbelly
instep38
36

back of handthighMean skin temperatures [°C]

Skin temperatures [°C](5) SET*40

lower arm
calf

34

32
30
28
26

0

5

10

15

20

time [min]

25

30

35

40
38
36
34
32
30
28
26

40

Case 50Case 5

130
110

90
70

50

0

5

10

15

20

time [min]

25

30

10

15

20

time [min]

25

30

35

40

30

35

40

(7) Mean skin temperature
85
Heart rate[/min]

Blood pressure [mmHg](6) Skin temperatures of Case 5
150

5

35

75
70
65
60
55

40

Case 580

05(8) Systolic blood pressure and diastolic blood pressure

10

15

20

time [min]25(9) Heart rate

Fig. 6: Results of Case 5 (walking along a course).
unsteady environment and did not remain in a hot or cold
3.5

Case 5 (Walking along a course)

environment for prolonged periods of time. However, only theFig. 6 summarises the results of Case 5, walking along a course.

skin tempareture of the back of the hand had a high response to

Fig. 6 (6) presents that only the skin tempareture of the back of

the thermal environment.

the hand changed intricately while that of other parts had small

The diastolic blood pressure was maintained almost constantchange. The range of variation in mean skin temperature waswhile the systolic blood pressure decreased as time passed, as

smaller in Case 5 than in other Cases, as shown in Fig. 6 (7).

shown in Fig. 6 (8).

This was likely because the subject was exposed to a very

- 52 -

3.6

Amount of evaporated sweat

outdoor thermal comfort, Energy and Buildings, 34(2002),

Table 3 shows the amount of evaporated sweat of each Case.

pp.661–665.

Comparing Case 1 and Case 2 conducted on the same day, the(5)

C.P. Yaglou, D. Minard, Control of heat casualties atamount of evaporated sweat increased due to solar radiation. The

military training centers, A.M.A. Arch. Ind.

more sweating occurred by walking in Case 4 compared with

Health,16-4(1957), pp.302-316

Case 3.

(6)
Table 3: Amount of Evaporated sweat

Hong Huang, Ryozo Ooka, Shinsuke Kato, Urban thermal
environment measurements and numerical simulation for

Case

Evaporated sweatDate

an actual complex urban area covering a large district

1

36 g

26 th

heating and cooling system in summer, Atmospheric

2

191 g

26 th

Environment, 39(2005), pp.6362-6375(7)

Akashi Mochida, Hiroshi Yoshino, Satoshi Miyauchi,

3

15 g

28 th

4

46 g

28 th

Teruaki Mitamura, Total analysis of cooling effects of

5

55 g

30 th

cross-ventilation affected by microclimate around abuilding, Solar Energy, 80(2006), pp.371-382(8)

4. Conclusions

Jutta Holst, Helmut Mayer, Urban human-biometeorology:
Investigations in Freiburg (Germany) on human thermal(1)

Simultaneousenvironments
performed

andmeasurements
human

of

physiologicaloutdoorcomfort, International Association for Urban Climate,thermalresponses

38(2010), pp.5-10

were
(9)

to determine how changeable environmental

Yingli Xuan, Guang Yang, Qiong Li, Akashi Mochida,conditions in outdoor space affected pedestrians.

Optimal building arrangement to maximize thermal(2) The results of these measurements were as follows.

acceptance of outdoors under different climates,(a) When mean wind velocity changed from approx. 0 m/s to 1.4
m/s, skin temperature decreased gradually.
(b) When MRT changed from 20 °C to 75 °C, skin temperature

Proceedings of 8th International Conference on Urban
Climates (2012), p.291.
(10) Saori Yumino, Taiki Uchida, Kiyoshi Sasaki, Hikaru

increased rapidly even though mean wind velocity was 1.2 m/s.

Kobayashi, Akashi Mochida, Total assessment for various(c) When environmental condition, especially MRT, changed

environmentally conscious techniques from threesuddenly, skin temperatures varied greatly at the body parts

perspectives, Mitigation of global warming, mitigation ofcovered without any clothes.

UHIs, and adaptation to urban warming, Sustainable Cities
and Society, 19 (2015), pp.236-249.

(d) Skin temperature during walking was lower than that during(11) Yasuhiro Nakamura, Daisuke Ida, Minoru Mizuno,

standing.

Evaluation of thermal comfort of unsteady andInhomogeneous thermal environment in the outdoors,

Acknowledgements

Transactions of the Society of Heating, Air-conditioning
This work was supported by the JSPS Grant-in-Aid for

and Sanitary Engineers of Japan,93(2004), pp.1-10

Scientific Research (B) (Grant number 26289200), and by the(12) J. D. Hardy, E. F. DuBois, The technic of measuring

joint research project of the Wind

radiation and convection, The Journal of Nutrition 15-5

Engineering Joint(1938), pp.461-475.

Usage/Research Center, Tokyo Polytechnic University.

(Received Apr. 30, 2017, Accepted Jul. 7, 2017)

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