To investigate how illuminance and color temperature in illumination affect the autonomic nervous system and central nervous system in conditions tending to lower physiological activity, and with an ordinary residential setting in mind, we performed an experiment on 8 healthy male subjects. The experimental conditions consisted of 4 conditions provided by a combination of 2 levels of color temperature (3000 K, 5000 K) and 2 levels of illuminance (30 lx, 150 lx). Physiological measurement was carried out during a process of 22 minutes of light exposure followed by 20 minutes of sleep in darkness. Heart rate variability (HRV) was used as an index of the autonomic nervous system, and alpha attenuation coefficient (AAC) and mean frequency of EEG were used as indices of the central nervous system. Subjective evaluation of drowsiness during the experiment was also carried out immediately following the 20 minutes sleep. No effect on HRV from illumination was noted, but significantly (p<0.05) lower values for AAC were obtained under 3000 K conditions than 5000 K conditions in measurements during the first half of light exposure (Session 1). During alpha attenuation testing, significantly (p<0.05) lower values for mean frequency in the θ-β EEG bandwidth were also obtained under 3000 K conditions than 5000 K conditions, but that pattern persisted in measurement during the second half of light exposure (Session 2). Subjective drowsiness was also higher under 3000 K conditions than 5000 K conditions. These results suggest that low color temperature light creates a smooth lowering of central nervous system activity, and that low color temperature illumination can be used effectively in a bedroom or other such environment where it is desirable to facilitate lowered physiological activity.
The objective of this study was to determine the change in elite dinghy sailor’s knowledge and use of sport science, three years after the adoption of a sport science support (SSS) programme by Yachting New Zealand for its elite dinghy sailors. A questionnaire was administered to 28 (22 male, six female) elite sailors in April 1994 and to 33 (24 male and nine female) in March 1997 during a training camp for elite sailors. 15 of the sailors participated in 1994 and 1997. The questionnaire asked whether or not the sailors used a training race diary and inquired about their knowledge and use of sport science in the areas of nutrition, psychology and physical conditioning. In 1997, additional questions enquired about sailor’s perception of sport science and its affect on their racing performance. Between April 1994 and March 1997, sailors received sport science support in nutrition, psychology and physical conditioning. Sailors reported a greater amount of fluid drunk on a four-hour sail in 1997 than in 1994 and a greater proportion of sailors ate a high carbohydrate meal after a race in 1997 than in 1994. In 1997, sailors reported feeling less anxiety before a race, and the sailors common to 1994 and 1997 reported feeling less sick before a race in 1997 than in 1994. Increases were observed in volume and intensity of physical training, and improvements were noticed in the chosen type of aerobic training in 1997. Most sailors believed that their knowledge and use of sport science has increased and that their increased use of sport science has led to improvements in racing performance. The results suggest that elite New Zealand sailors’ use of sport science improved in the areas of nutrition, sports psychology and physical conditioning between 1994 and 1997. However, when the results were compared with those of Legg and Mackie (1999), it was evident that greater physical conditioning improvements had occurred between 1994 and 1995 than had been sustained since, while the majority of sailor’s sport psychology improvements occurred between 1995 and 1997. Sailors reported fluid intake between 1994 and 1997 had steadily improved. The reason for sailor’s change in emphasis on different areas of sport science over time may be a result of their adopting ideas with which they were most familiar (physical conditioning and nutrition) first, and then adopting the less widely understood discipline of sport psychology once they felt that they had mastered their use of physical conditioning and nutrition. This study indicates that sailors are beginning to understand the importance of personal preparation using sport science principles.
A heated full-scale hand model has been used to determine indirectly hand and finger heat losses of human subjects exposed to four ambient cold conditions (0, 4, 10 and 16°C, air velocity =0.3 m/s). Heat transfer coefficients determined with the hand model, were used to calculate heat flux based on measured skin to ambient temperature gradients. The responses of eight subjects from a previous study were used for the analysis. The measurements were carried out in a small climate chamber which was cooled by evaporating liquid carbon dioxide. The thermal hand was put into the chamber in a vertical position with the thumb up. The surface temperature of the thermal hand was controlled at 21, 25, 28, 31 and 34°C under each of the four ambient cold conditions, in order to investigate possible temperature dependence of the calculated combined convective and radiate heat transfer coefficient (hCR). The value of hCR varied between approximately 9-13 W/m2°C for fingers and palm and back of hand, respectively. Calculated heat losses showed significant individual variation, corresponding to the maintained skin to ambient temperature gradient. Individual values from about 50 to more than 300 W/m2 were calculated. Several subjects showed CIVD and heat fluxes associated with this phenomenon were sometimes doubled. The measurement results showed realistic and comparable with literature date. The advantages of the thermal hand model can be counted as easy to use; directly measures the heat loss; highly reproducible and no interruption. It appears that a heated hand model provides a useful methods for analysis and quantification of hand heat loss.
This research clarified the changes in body shape among Japanese women aged in their 20’s, by measuring the subcutaneous fat distribution over the whole body and its circumference at certain points. The subjects, 13 healthy women, were measured twice, once in their early 20’s and 5 years later in their late 20’s. Subcutaneous fat thickness was measured at 14 points on the body using the B-mode ultrasound method and the body size was measured directly at 8 points on the body using a steel measure. Subcutaneous fat thickness tends to increase with age, except at the cheek, neck, bust and leg. Significant increases were detected especially at lower parts of the trunk such as the waist and infragluteal region. Meanwhile, despite the significant change in subcutaneous fat thickness, the circumferences measured did not change, and also weight tended to decrease with age. Based on this finding, except for fat, body mass, such as muscle and bone, decreases with age due to decreased exercise and changes in calorie intake. Cluster analysis of the accumulation patterns of subcutaneous fat indicated that there were the following 3 patterns of subcutaneous fat accumulation from the early 20’s to the late 20’s. I. Accumulation on the whole trunk (bust, abdomen, waist and back) and upper arm - trunk/upper arm accumulation pattern II. Significant accumulation around waist - waist accumulation pattern III. Even accumulation at abdomen, side abdomen, hip and lower hip - abdomen/hip accumulation pattern