Outdoor thermal physiology along human pathways: a study using a wearable measurement system

• Published in: International journal of biometeorology Vol. 59; no. 5; pp. 503 - 515
• Main Authors: Nakayoshi, Makoto, Kanda, Manabu, Shi, Rui, de Dear, Richard
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.05.2015; Springer Nature B.V
• Subjects: Acclimatization - physiology; Activities of Daily Living; Adult; Aged; Ambient temperature; Animal Physiology; Biological and Medical Physics; Biophysics; Body size; Body Temperature Regulation - physiology; Canyons; Climate; Earth and Environmental Science; Environment; Environmental Health; Environmental Monitoring - methods; Female; Heat exchange; Humans; Japan; Male; Meteorology; Microclimate; Middle Aged; Monitoring, Ambulatory - methods; Original Paper; Outdoors; Pedestrians; Physiological responses; Physiology; Plant Physiology; Skin; Spatio-Temporal Analysis; Studies; Temperature; Walking - physiology; Wind speed; Young Adult; Japan; Sweat rate; Mobile observation; Mean radiant temperature; Outdoor thermal comfort; Outdoor thermal physiology; Globe thermometer
• ISSN: 0020-7128; 1432-1254
• DOI: 10.1007/s00484-014-0864-y

An outdoor summer study on thermal physiology along subjects’ pathways was conducted in a Japanese city using a unique wearable measurement system that measures all the relevant thermal variables: ambient temperature, humidity, wind speed ( U ) and short/long-wave radiation ( S and L ), along with some physio-psychological parameters: skin temperature ( T skin ), pulse rate, subjective thermal sensation and state of body motion. U , S and L were measured using a globe anemo-radiometer adapted use with pedestrian subjects. The subjects were 26 healthy Japanese adults (14 males, 12 females) ranging from 23 to 74 years in age. Each subject wore a set of instruments that recorded individual microclimate and physiological responses along a designated pedestrian route that traversed various urban textures. The subjects experienced varying thermal environments that could not be represented by fixed-point routine observational data. S fluctuated significantly reflecting the mixture of sunlit/shade distributions within complex urban morphology. U was generally low within urban canyons due to drag by urban obstacles such as buildings but the subjects’ movements enhanced convective heat exchanges with the atmosphere, leading to a drop in T skin . The amount of sweating increased as standard effective temperature (SET*) increased. A clear dependence of sweating on gender and body size was found; males sweated more than females; overweight subjects sweated more than standard/underweight subjects. T skin had a linear relationship with SET* and a similarly clear dependence on gender and body size differences. T skin of the higher-sweating groups was lower than that of the lower-sweating groups, reflecting differences in evaporative cooling by perspiration.