|Takafumi Maeda||Last modified date：2018.09.04|
Field of Specialization
Physiological Anthropology, Environmental Ergonomics, Thermal Physiology
Research InterestsMembership in Academic Society
- Physiological Polymorphism of Cold-induced Thermogenesis and Vasoconstriction in Human
keyword : Physiological Anthropology, Environmental Adaptability, Cold Tolerance, Physiological Polymorphism
- Evaluation method for the actibity of Brown Adipose Tissue
keyword : Environmental Adaptability, Cold Tolerance, Brown Adipose Tissue
- Evaluation of Thermoregulation Ability and its modifying factors
keyword : Environmental Adaptability, Thermoregulation Ability, Lifesyle, Living Environment
- Effects of Humidity on Human Immno Function
keyword : Humidity, Immuno Function, Stress
- Effects of Indoor Environmental Factors (Air Temperature, Air Movement, Humidity, Air Quality) and Local Thermal Stimuli on Mental Task Performance
keyword : Task Performance, Cold, Hot, Local Heating, Local Cooling, CO2, air velocity, relative humidity
|1.||Takafumi Maeda, Relationship between maximum oxygen uptake and peripheral vasoconstriction in a cold environment, Journal of Physiological Anthropology, https://doi.org/10.1186/s40101-017-0158-2, 36, 42, 2017.12, Various individual characteristics affect environmental adaptability of a human. The present study evaluates the relationship between physical fitness and peripheral vasoconstriction in a cold environment.
Seven healthy male students (aged 22.0 years) participated in this study. Cold exposure tests consisted of supine rest for 60 min at 28 °C followed by 90 min at 10 °C. Rectal and skin temperatures at seven sites, oxygen consumption, and the diameter of a finger vein were measured during the experiment. Metabolic heat production, skin heat conductance, and the rate of vasoconstriction were calculated. Individual maximum oxygen consumption, a direct index of aerobic fitness, was measured on the day following the cold exposure test.
Decreases in temperature of the hand negatively correlated with the changes in rectal temperature. Maximum oxygen consumption and the rate of vasoconstriction are positively correlated. Furthermore, pairs of the following three factors are also significantly correlated: rate of metabolic heat production, skin heat conductance, and the rate of vasoconstriction.
The results of this study suggested that the capacity for peripheral vasoconstriction can be improved by physical exercise. Furthermore, when exposed to a cold environment, fitter individuals could maintain metabolic heat production at the resting metabolic level of a thermoneutral condition, as they correspondingly lost less heat..
|2.||Takafumi Maeda, Tetsuhito Fukushima, Keita Ishibashi, Shigekazu Higuchi, Involvement of Basal Metabolic Rate in Determination of Type of Cold Tolerance, Journal of Physiological Anthropology, http://doi.org/10.2114/jpa2.26.415, 26, 3, 415-418, 2007.07, This study aimed to assess the relationship between basal metabolic rate (BMR) and metabolic heat production, and to clarify the involvement of BMR in determining the phenotype of cold tolerance. Measurements of BMR, maximum oxygen uptake, and cold exposure test were conducted on ten males. In the cold exposure test, rectal (Trec) and mean skin temperatures (Tms), oxygen uptake, and blood flow at forearm (BFarm) were measured during exposure to cold (10°C) for 90 min. Significant correlations were observed between BMR and increasing rate of oxygen uptake, as well as between decreasing rate of BFarm and increasing rate of oxygen uptake at the end of cold exposure. These findings suggested that individuals with a lower BMR were required to increase their metabolic heat production during cold exposure, and that those with a higher BMR were able to moderate increased metabolic heat production during cold exposure because they were able to reduce heat loss. This study showed that BMR is an important factor in determining the phenotype of cold tolerance, and that individuals with a low BMR showed calorigenic-type cold adaptation, whereas subjects with a high BMR exhibited adiabatic-type cold adaptation by peripheral vasoconstriction..|
|3.||Takafumi Maeda, Mitsuhiro Ohta, Shin-Ya Kaneko, Hideyuki Kanda, Tetsuhito Fukushima, Relationships between heatstroke symptoms and lifestyles in Japanese forestry workers, Journal of the Human-Environment System, http://doi.org/10.1618/jhes.13.1, 13, 1, 1-6, 2011.07, Several risk factors for heatstroke among forestry workers were previously reported, but the effects of lifestyles of the workers on heatstroke symptoms remain unknown. This study examines the effects of lifestyles on heatstroke symptoms among Japanese forestry workers during the summer. We distributed a questionnaire to 97 forestry workers about heatstroke symptoms, hydration, hotness in workplace, lifestyles including food consumption, sleep duration, exercise, alcohol consumption, and smoking, age, and years of forestry service, and measured physical characteristics. The total health score was used as an index of healthy habits. Thirty-seven workers (38.1%) experienced heatstroke symptoms. Heatstroke and asymptomatic groups significantly differed in terms of age, years of forestry service, frequency and volume of hydration, frequency of urination, and perceived hotness. Logistic regression analysis selected the following key variables associated with the development of heatstroke symptoms: years of forestry service, frequency of hydration adjusted by frequency of urination, and total health score. In conclusion, the present study revealed that one third of forestry workers develop some early symptoms of heatstroke during work, and healthy habits reduce the risk of heatstroke in forestry workers..|
|4.||Takafumi Maeda, Shin-Ya Kaneko, Mitsuhiro Ohta, Kazuko Tanaka, Akihiko Sasaki, Tetsuhito Fukushima, Risk factors for heatstroke in Japanese forestry workers, Journal of Occupational Health, http://doi.org/10.1539/joh.48.223, 48, 4, 223-229, 2006.08, We examined the risk factors for heatstroke among forestry workers in Japan during the summer. We distributed a questionnaire to 124 forestry workers to determine heatstroke symptoms, degree of sweating and hydration, as well as perceived hotness and amount of sunlight at work sites. Forty of the workers (32.3%) reported experiencing heatstroke symptoms. Thirteen and 21 of them reported such symptoms during July and August, respectively. Eleven workers experienced heatstroke at around 14:00; 5 and 4 developed symptoms at around 11:00 and 10:00, respectively. Groups with and without heatstroke symptoms significantly differed in terms of perceived hotness (p<0.05), sunlight (p<0.05), degree of sweating (p<0.01) and frequency of hydration (p<0.05) while working. Heatstroke symptoms developed in 60.6% of workers aged up to 50 yr, but in only 22.0% of those over the age of 51 (p<0.01). Multiple regression analysis selected the following key variables associated with the development of heatstroke symptoms (R2=0.236 and p=0.006): frequency of urination, hotness, BMI and years of forestry work (standard coefficients: +0.229, +0.194, +0.280 and -0.162, respectively). The results of the present study showed that one third of forestry workers developed some symptoms of early heatstroke during summer forestry work. Furthermore, the results indicate that a short duration of forestry service was one of the risk factors contributing to the onset of heatstroke, in addition to heat stress, loss of body water and electrolytes, and obesity..|
|5.||Takafumi Maeda, Akiko Sugawara, Tetsuhito Fukushima, Shigekazu Higuchi, Keita Ishibashi, Effects of Lifestyle, Body Composition, and Physical Fitness on Cold Tolerance in Humans, Journal of Physiological Anthropology and Applied Human Science, http://doi.org/10.2114/jpa.24.439, 24, 4, 439-443, 2005.08, [URL], In the present study, we attempted to clarify the effects of lifestyle and body compositions on basal metabolism and to clarify the effects of physical training on thermoregulatory responses to cold. Basal metabolism, body compositions, and questionnaires regarding lifestyle were evaluated in 37 students. From multiple linear regression analysis, sex, muscle weight, fat intake, and diurnal temperature were selected as significant explanatory variables. In a second experiment, rectal and the skin temperature at 7 different points as well as the oxygen uptake of eight males were measured at 10°C for 90 min before and after training. The decline in rectal temperature that was observed before training was not observed after training. In addition, rectal temperature was significantly higher at post-training than at pre-training. These results suggest that some lifestyle factors affect cold tolerance; in particular, daily activity might improve our ability to control heat radiation and basal heat production..|
|6.||Takafumi Maeda, Perspectives on Environmental Adaptability and Physiological Polymorphism in Thermoregulation, Journal of Physiological Anthropology and Applied Human Science, http://doi.org/10.2114/jpa.24.237, 24, 3, 237-240, 2005.06, [URL].|
|7.||Takafumi Maeda, Akira Yasukouchi, Blood Lactate Disappearance during Breathing Hyperoxic Gas after Exercise in Two Different Physical Fitness Groups: on The Work Load Fixed at 70%VO2max, Applied Human Science, http://doi.org/10.2114/jpa.16.249, 16, 6, 249-256, 1997.10, The purpose of this study is to evaluate effects of breathing hyperoxic gas on blood lactate disappearance after submaximal exercise in two different physical fitness groups and to clarify the most effective oxygen concentration in each group. Fourteen healthy male students participated as subjects in this study. They were divided in two groups by difference in their anaerobic threshold (AT). Seven males were treated as Higher AT group and the others as Lower AT group. Subjects wore a T-shirt, short pants and sports shoes and performed three sessions; each consisting of five minutes of exercise and six minutes of rest, at a workload of 70% VO2max On a bicycle ergometer. Hyperoxic gas was breathed only during recovery periods. Oxygen rates of 21, 30, 40, 60, 80 and 100% in inspired gas were employed. According to the results of blood lactate (BLA), the most effective oxygen condition on BLA disappearance was obtained over 60% in Higher AT group and at 30% oxygen in Lower AT group. Thus, it was especially noteworthy that the effects of hyperoxic gas in Higher AT group were different from those of Lower AT group. It is thought that the effects of breathing hyperoxic gas were dependent on physical fitness, which have caused many reports to be in conflict hitherto..|
|8.||Takafumi Maeda, Akira Yasukouchi, Blood Lactate Disappearance during Breathing Hyperoxic Gas after Exercise in Two Different Physical Fitness Groups: on The Work Load Fixed at 130%AT, Applied Human Science, http://doi.org/10.2114/jpa.17.33, 17, 2, 33-40, 1998.02, This study aimed to investigate the effects of hyperoxic gas breathing on the disappearance of blood lactate after exercise in two groups having different physical fitness and to determine the most effective O2 concentration in consideration of workload. Our previous study has demonstrated that hyperoxic gas breathing brought out different effects among subjects. In respect of these effects, it was thought necessary to pay attention to exercise intensity. Therefore, the exercise intensity of this study was set by using relative workload of anaerobic threshold (AT) from the aspect of blood lactate. Ten healthy male students participated as subjects and were divided into 2 groups; a group consisting of 5 active students whose mean AT was 60.4% VO2max (Higher AT group) and the other group consisting of 5 inactive students having the mean AT of 48.8% VO2max (Lower AT group). All subjects underwent three cycles of ergometer exercise on a bicycle (workload; 130% AT) for 5 min and recovery session for 6 min. The hyperoxic gas breathing was given only for the recovery session. The conditions of breathing were air, 30, 40, 60 or 80% O2. Blood for determination of the blood lactate level was taken only in the recovery session. When compared with air-breathing, the blood lactate level was significantly reduced in the condition of more than about 60% O2 breathing in Higher AT group, but not in Lower AT one. Together with the previous findings, it was found that the blood lactate level was markedly reduced by more than 60% O2 breathing in Higher AT group without relation to the workload in the range of about 70 to 80% VO2max. In Lower AT group, however, the effects of hyperoxic gas breathing were dependent on the exercise intensity; 30% and 40% O2 breathings were effective for the subjects with more than about 65% VO2max, but not in a lower intensity than it. These results indicate that the effects of hyperoxic gas breathing on the disappearance of blood lactate are dependent on the exercise intensity and the physical capacity..|
- Japan Society of Physiological Anthropology
- Japan Ergonomics Society
- Japanese Society of Human-Environment System
- Japanese Society of Biometeorology
- Japan Society for Occupational Health
- Japanese Society of Physical Fitness and Sports Medicine
- Japanese Society for Hygiene