gyoon Chun

A Study on Bedroom Environment and Sleep Quality in Korea

The purpose of this study was to investigate both the sleep environment and sleep quality in bedrooms. It was also to reveal the relationship between sleep environment and sleep quality, and to study its seasonal changes in winter, spring, and summer. The subjects for this study were 24 women who lived in apartments in Seoul and its environs. We conducted two groups of measurements. One group considered elements of the sleep environment: mean radiant temperature, air temperature, relative humidity, carbon dioxide (CO2) concentration, illumination, and equivalent noise level. The other looked at elements of sleep quality: the apnea— hypopnea index, and inspiratory flow limitation (as %FL), which were measured simultaneously while subjects were asleep. Results showed first, that people were exposed to a variety of problems when asleep, related to their sleep environment such as too low or high air temperatures, or relative humidity and high CO2 concentrations. Second, these were seasonally dependant and people slept best during spring, then winter, and then summer. Third, the effect of the sleep environment on sleep quality varied with age.

Predicting indoor thermal sensation for the elderly in welfare centres in Korea using local skin temperatures

This study aims to develop a method to predict thermal sensation in elderly people. To identify the point on the body where skin temperature can best predict thermal sensation in elderly people aged 65 or older and develop a thermal comfort measurement model that can replace the psychological scale, experiments were conducted in a stainless steel wall finish climate chamber and at the seven senior welfare centres in Korea. The results of the climate chamber experiment with 30 healthy elderly people (15 males, 15 females) showed that there was a correlation between thermal sensation and local skin temperature on the back of the hand, the upper arm, the top of the foot and the cheek. This developed thermal sensation prediction model was then applied in a field study at senior welfare centres to verify whether the model could be applied to a large number of elderly subjects in different locations. The field study with 294 elderly people (111 males, 183 females) shows that cheek and back of the hand skin temperatures were useful in predicting thermal sensation in the elderly, and predicted thermal sensation based on the skin temperature of the cheek had the strongest correlation with thermal sensation among the participants.

Discrepancies between Physiological and Psychological Measures of Stress Associated with Indoor Temperature

To assess stress levels associated with thermal comfort, this study measured stress levels in different Predicted Mean Vote (PMV) conditions using verbal vote, electroencephalographic (EEG), and salivary α-amylase assessments. This study was conducted in a climate chamber to regulate and experimentally manipulate PMV conditions. Environmental factors were set to 7 different PMV levels, from −3 to +3 by units. EEGs were measured for each subject using 8 electrodes covering the frontal, temporal, and parietal lobes, for 65 min for each PMV condition. Following EEG collection, saliva samples (for alpha (α)-amylase quantification) and a verbal report were gathered for each subject. The EEG and salivary α-amylase responses were similar, in that both tests showed the 0 to +2 conditions were relatively non-stressful compared to other conditions. On the other hand, the verbal reports indicated that the −1 to +1 conditions were relatively non-stressful.