Changes in thermal comfort, core temperature, and body weight during simulated parcel home-delivery in summer and winter

Abstract

Our aim was to determine differences in thermal comfort during simulated one-day parcel home delivery between summer and winter. Six young healthy males performed experiments in summer (up to 31°C) and winter (up to 8°C). After baseline measurement in a chamber, subjects drove a truck to a prespecified location for outside measurements. They performed 4 sets of 100-m walk with carrying 5-kg plate during the first 50-m walk at 100 m/min, separated by 7-min driving in each of the morning and the afternoon. Subjects could ingest water ad libitum in outside and set the cockpit temperature by themselves during driving. Thermal sensation and comfort were recorded using a subjective scale at the first and the last sets of each morning and afternoon session, while esophageal temperature (Tes) was monitored (thermocouples). Body weight was measured before and the end of experiment. We found that 1) whole-body comfort decreased in summer and the decrease was greater than winter with higher Tes and 2) changes in body weight were 0.7 and 0.3 kg through whole day in summer and winter, respectively. In summary, thermal comfort during working worsened in summer, possibly related with higher core temperature and greater decrease in body weight.

Factors correlated with drug use for constipation: perspectives from the 2016 open Japanese National Database

“…However, the mechanisms through which outside temperature and vigorous exercise affect stimulant laxative use are not clear. In previous reports, internal body temperature has been shown to be synchronized with outside temperature [18,19], increased with metabolic rate in dogs and humans [20,21] and with vigorous exercise [22], and decreased with aging [23]. Additionally, intestinal contraction or transit may affect in low internal temperature in humans, as demonstrated in an ex-vivo study [24] and may improve with vigorous exercise or external body warming using lumbar application of a 40°C hot compress in women with constipation [22,25].…”

Improving building thermal performance through an integration of Passivhaus envelope and shading in a tropical climate

“…Humans worldwide have the same essential physiology and a core temperature of around 36.5°C to 37.5°C, which is conceptualised as a thermodynamic machine in models to benchmark and maintain thermal comfort, regardless of great variety in human metabolism, activities, and cultural and climate differences (Roaf et al, 2005). The thermal sensation is also influenced by seasonal variations and outdoor weather; for instance, the summer temperature causes a higher core temperature and a greater decrease in body weight than winter (Nakayama et al, 2019). A study shows that the Asian groups consistently selected a personal cooling system (PCS) airflow temperature 5°C higher, leading to 1.9°C warmer microclimate temperatures close to the person's chest compared to the European groups; therefore, both the Chinese and the Japanese participants selected significantly warmer temperatures of the PCS than the white, middle-western-Europeans (Havenith et al, 2020).…”

Fundamental Concepts of Human Thermoregulation and Adaptation to Heat: A Review in the Context of Global Warming

“…In contrast, when Tc increases above the set-point, the ANS would stimulate peripheral vasodilation and channel more blood to the skin surface to dissipate heat to the environment [132,133,140]. Higher Tb also promotes heat dissipating behavior to seek cooler environment and to reduce insulation over the skin [141,142]. Physiologically, the skin plays important roles in Tb homeostasis by conserving heat (vasoconstriction) when Tc is below the set-point and by promoting heat dissipation (vasodilation) when Tc is higher than the set-point.…”

“…To avoid the heat from the sun, outdoor activities would likely begin closer to, or soon after sunset, and could extend to the next morning before dawn, or soon after sunrise. This projected shift towards a sub-nocturnal lifestyle could be associated with the limbic system, which drives human behavior to operate in a "comfort zone" [141,142,154]. A higher Tev is also associated with sub-optimal mood, mental functions, and motor skill and physical performances, which compromise occupational health and productivity, and sports performance [85,194,[236][237][238][239].…”