Effects of Indoor Thermal Environment on Human Food Intake, Productivity, and Comfort: Pilot, Randomized, Crossover Trial

Abstract

Objective: We hypothesized that exposure to mild temperatures above the human thermoneutral zone would decrease caloric intake in a sedentary office environment. Methods: Women (n = 25) were randomized in a crossover design to perform seated office work for 7 hours in a thermoneutral condition (control; 19–20°C) and a condition above the thermoneutral zone (warm; 26–27°C). Food intake was estimated by weight and bomb calorimetry, peripheral temperature by thermal imaging, and thermal comfort and productivity by questionnaires. Mixed effects models were used to examine the effects of thermal condition on caloric intake. Results: Participants ate on average 357 kcal less in the warm condition, adjusting for body mass index and peripheral temperature (p=0.0219). According to the survey results at midday (after 3.5 hours of exposure), 96% of the participants in the warm condition reported being comfortable (n=24) compared with 32% in the control condition (n=8). More participants reported being as productive or more productive than usual in the warm condition (n=22, 88%) than in the control condition (n=12, 48%). Conclusions: This line of research is worthy of further exploration. Untightening climate control towards warmer conditions during summer to increase comfort and productivity while decreasing caloric intake may prove both effective and comfortable.

Impact of Indoor Air Quality and Multi-domain Factors on Human Productivity and Physiological Responses: A Comprehensive Review

“…In examining the demographic aspects, we discovered that 93 out of 420 papers included data on participant gender. Among these, 18% (e.g., [132][133][134][135][136][137][138][139][140][141][142][143][144]) were exclusively male, while 6% (e.g., [94,[145][146][147][148]) were solely femalefocused. The remaining majority (e.g., [37,149,150]) carried out research involving both genders.…”

“…As for racial demographics, only a handful of studies [148,161] have specified this information. Since many studies recruit their participants locally, we also examined regional distribution, as depicted in Figure 6.…”

“…Many studies have unbalanced samples in terms of age, gender, and occupation, or focused on specific demographics (e.g., young, healthy college students, or female subjects) that did not represent office workers as a whole, which can introduce bias and limit the applicability of results [36,132,191,203,253,254]. These studies limited the generalizability of their findings [145,148]. The proper simple size depends on several factors including number of impact factors, variability, level of significance, and feasibility of resources.…”

Biomimetic Aligned Micro-/Nanofibrous Composite Membranes with Ultrafast Water Transport and Evaporation for Efficient Indoor Humidification

“…Environmental humidity has aroused more concern for its effects on indoor air quality, human comfort, and health. − The optimum ambient relative humidity (RH) for a healthy and comfortable environment ranges from 40 to 60%. − Low RH can enhance viral transmission, cause respiratory problems, damage electronic equipment, and even lead to explosions in industrial workshops. − Considering the significance of humidity, environmental humidity management has been introduced to ensure a safe and healthy environment for human life and meet the needs of industrial production processes. , Various humidification methods have been reported to effectively control the ambient RH, such as centrifugal, ultrasonic, direct steam, and wet film humidification. − Among them, evaporative humidifiers with porous membranes as core elements have been widely used due to their advantages of low energy consumption, simple process, and wide humidification range. When dry air passes through the water-soaked humidifying element in this humidifier, water fully absorbs the heat of dry air and then evaporates from the porous wetted membrane to increase the humidity in air. , …”