Showing papers in "Journal of Physiological Anthropology in 2013"

Physiological and psychological effects of walking on young males in urban parks in winter.

Abstract: Background Interaction with nature has a relaxing effect on humans. Increasing attention has been focused on the therapeutic effects of urban green space; however, there is a lack of evidence-based field research. This study provided scientific evidence supporting the physiological and psychological effects of walking on young males in urban parks in winter.

Psychological and physiological effect in humans of touching plant foliage - using the semantic differential method and cerebral activity as indicators.

Abstract: Numerous studies have reported on the healing powers of plants and nature, but there have not been so many instances of experimental research. In particular, there are very few psychological and physiological studies using tactile stimuli. This study examines the psychological and physiological effects of touching plant foliage by using an evaluation profile of the subjects’ impressions and investigating cerebral blood flow. The subjects were 14 young Japanese men aged from 21 to 27 years (mean ± standard deviation: 23.6 ± 2.4). With their eyes closed, the subjects touched four different tactile samples including a leaf of natural pothos (Epipremnum aureum). The physiological indices were compared before and after each stimulus. Psychological indices were obtained using a ‘semantic differential’ method. The fabric stimulus gave people ‘soft’ and ‘rough’ impressions, ‘kind’, ‘peaceful’ and ‘pleasant’ feelings psychologically, and a sense of physiological calm. On the other hand, the metal stimulus gave people ‘cold’, ‘smooth’ and ‘hard’ impressions and an image of something ‘artificial’. The metal stimulus caused a stress response in human cerebral blood flow although its evaluation in terms of ‘pleasant or unpleasant’ was neutral. There were no remarkable differences between the stimuli of natural and artificial pothos compared with other types of stimulus psychologically. However, only the natural pothos stimulus showed a sense of physiological calm in the same appearance as the fabric stimulus. This study shows that people experience an unconscious calming reaction to touching a plant. It is to be concluded that plants are an indispensable element of the human environment.

Validity of ultrasound muscle thickness measurements for predicting leg skeletal muscle mass in healthy Japanese middle-aged and older individuals

Abstract: The skeletal muscle mass of the lower limb plays a role in its mobility during daily life. From the perspective of physical resources, leg muscle mass dominantly decreases after the end of the fifth decade. Therefore, an accurate estimate of the muscle mass is important for the middle-aged and older population. The present study aimed to clarify the validity of ultrasound muscle thickness (MT) measurements for predicting leg skeletal muscle mass (SM) in the healthy Japanese middle-aged and older population. MTs at four sites of the lower limb and the bone-free lean tissue mass (LTM) of the right leg were determined using brightness-mode ultrasonography and dual-energy X-ray absorptiometry (DXA), respectively, in 44 women and 33 men, 52- to 78-years old. LTM was used as a representative variable of leg skeletal muscle mass. In the model-development group (30 women and 22 men), regression analysis produced an equation with R2 and standard error of the estimate (SEE) of 0.958 and 0.3 kg, respectively: LTM (kg) = 0.01464 × (MTSUM×L) (cm2) - 2.767, where MTSUM is the sum of the product of MTs at four sites, and L is length of segment where MT is determined. The estimated LTM (7.0 ± 1.7 kg) did not significantly differ from the measured LTM (7.0 ± 1.7 kg), without a significant systematic error on a Bland-Altman plot. The application of this equation for the cross-validation group (14 women and 11 men) did not yield a significant difference between the measured (7.2 ± 1.6 kg) or estimated (7.2 ± 1.6 kg) LTM and systematic error. The developed prediction equation may be useful for estimating the lean tissue mass of the lower extremity for the healthy Japanese middle-aged and older population.

Individual differences in the physiological effects of forest therapy based on Type A and Type B behavior patterns

Abstract: In recent years, the physiological relaxation effects of natural environments have been widely exploited, and although individual differences in the effects of forest therapy are known, assessment methods have not been clearly established. This study used a classification based on Type A and Type B behavior patterns to explain individual differences in physiological responses to forest environments. We performed physiological experiments in 44 forest and urban (controls) areas. In total, 485 male university students (age, 21.8 ± 1.6 years) participated in the study. The subjects were asked to visit forest or urban environments randomly and observe each landscape for 15 min. The subjects’ pulse rates and blood pressures were tested to evaluate their physiological responses. The Kwansei Gakuin daily life questionnaire was used to identify Type A and Type B behavior patterns in subjects. The pulse rate was significantly lower in the Type B group after exposure to forest areas than after exposure to urban areas, whereas no significant difference was observed in the Type A group. In addition, the pulse rate was significantly lower in the low scoring subjects in the Type B group, which was consistent with changes in their diastolic blood pressure. These results suggest that individual differences in pulse rate and blood pressure in response to forest environments can be explained by Type A and Type B behavior patterns.

Evaluation of mental stress by physiological indices derived from finger plethysmography

Abstract: Quantitative evaluation of mental stress is important to prevent stress-related disorders. Finger plethysmography (FPG) is a simple noninvasive method to monitor peripheral circulation, and provides many physiological indices. Our purpose is to investigate how FPG-derived indices reflect on mental stress, and to clarify any association between these physiological indices and subjective indices of mental stress. Thirty-one healthy women (mean age, 22 years ± 2) participated. The participants rested by sitting on a chair for 10 min. They then performed a computerized version of the Stroop color-word conflict test (CWT) for 10 min. Finally, they rested for 10 min. FPG was recorded throughout the experiment. The participants completed a brief form of the Profile of Mood States (POMS) questionnaire before and after the test. Using the FPG data, we conducted chaos analysis and fast Fourier transform analysis, and calculated chaotic attractors, the largest Lyapunov exponent, a high-frequency (HF) component, a low-to-high-frequency (LF/HF) ratio, finger pulse rate and finger pulse wave amplitude. The HF component decreased and the LF/HF ratio increased significantly during the test (P < 0.01), while the confusion subscale of POMS increased after the test (P < 0.05). During testing, finger pulse rate significantly increased (P < 0.001), and the finger pulse wave amplitude decreased (P < 0.001). The attractor size reduced during testing and returned to a baseline level afterwards. Although the largest Lyapunov exponent showed no significant change during testing, significant negative correlation with the tension-anxiety subscale of POMS was observed at the beginning (P < 0.01). A significant negative correlation between the LF/HF ratio and two subscales was also observed in the beginning and middle of the test (P < 0.05). There were no correlations during the rest periods. The physiological indices derived from FPG were changed by mental stress. Our findings indicate that FPG is one of the easiest methods to evaluate mental stress quantitatively. In particular, the largest Lyapunov exponent and the LF/HF ratio might be associated with acute mental stress. Farther examination is needed to find any association between the physiological indices and various types of mental stress.

Oxygen uptake, heart rate, perceived exertion, and integrated electromyogram of the lower and upper extremities during level and Nordic walking on a treadmill

Abstract: The purpose of this study was to characterize responses in oxygen uptake ( ), heart rate (HR), perceived exertion (OMNI scale) and integrated electromyogram (iEMG) readings during incremental Nordic walking (NW) and level walking (LW) on a treadmill. Ten healthy adults (four men, six women), who regularly engaged in physical activity in their daily lives, were enrolled in the study. All subjects were familiar with NW. Each subject began walking at 60 m/min for 3 minutes, with incremental increases of 10 m/min every 2 minutes up to 120 m/min , and HR were measured every 30 seconds, and the OMNI scale was used during the final 15 seconds of each exercise. EMG readings were recorded from the triceps brachii, vastus lateralis, biceps femoris, gastrocnemius, and tibialis anterior muscles. was significantly higher during NW than during LW, with the exception of the speed of 70 m/min (P < 0.01). and HR were higher during NW than LW at all walking speeds (P < 0.05 to 0.001). OMNI scale of the upper extremities was significantly higher during NW than during LW at all speeds (P < 0.05). Furthermore, the iEMG reading for the VL was lower during NW than during LW at all walking speeds, while the iEMG reading for the BF and GA muscles were significantly lower during NW than LW at some speeds. These data suggest that the use of poles in NW attenuates muscle activity in the lower extremities during the stance and push-off phases, and decreases that of the lower extremities and increase energy expenditure of the upper body and respiratory system at certain walking speeds.

Effects of a late supper on digestion and the absorption of dietary carbohydrates in the following morning

Abstract: Our previous experiment showed that the light intensity exposed on the subjects during evening time had no effect in the following morning on the efficiency of the digestion and absorption of dietary carbohydrates ingested at a usual suppertime. People who keep late hours usually have a late suppertime; thus, we examined the effects of a late suppertime on gastrointestinal activity in the following morning in comparison to that of a usual suppertime. Twelve female university students volunteered as paid participants. The breath hydrogen test was carried out to estimate the amount of unabsorbed dietary carbohydrates and the percentage of the total amount of dietary carbohydrates in the breakfast that were unabsorbed, as well as to estimate oro-cecal transit time. The respiratory quotient was also measured to find the ratio of carbohydrates/lipid metabolism in the post-breakfast state. Subjects’ peripheral blood glucose concentration was measured by a blood glucose meter. The subjects participated under two different experimental conditions: with a usual suppertime (having supper at 18:00) and a late suppertime (having supper at 23:00). The efficiency of the digestion and absorption of dietary carbohydrates in the breakfast under late suppertime conditions was higher than that under usual suppertime conditions. Usual or late suppertime had no effect on the ratio of carbohydrates to lipids oxidized after the subjects had breakfast. There were significant differences in the blood glucose level between the two conditions at 30, 60, 120, 150, and 180 minutes after having breakfast, whereas the mean blood glucose level under late suppertime conditions was significantly higher than under usual suppertime conditions. Having a late supper showed a worse effect on postprandial serum glucose profiles the following morning. This study confirmed that keeping our usual meal timing is important for our health.

Clothing insulation and temperature, layer and mass of clothing under comfortable environmental conditions

Abstract: This study was designed to investigate the relationship between the microclimate temperature and clothing insulation (Icl) under comfortable environmental conditions. In total, 20 subjects (13 women, 7 men) took part in this study. Four environmental temperatures were chosen: 14°C (to represent March/April), 25°C (May/June), 29°C (July/August), and 23°C (September/October). Wind speed (0.14ms-1) and humidity (45%) were held constant. Clothing microclimate temperatures were measured at the chest (Tchest) and on the interscapular region (Tscapular). Clothing temperature of the innermost layer (Tinnermost) was measured on this layer 30 mm above the centre of the left breast. Subjects were free to choose the clothing that offered them thermal comfort under each environmental condition. We found the following results. 1) All clothing factors except the number of lower clothing layers (Llower), showed differences between the different environmental conditions (P<0.05). The ranges of Tchest were 31.6 to 33.5°C and 32.2 to 33.4°C in Tscapular. The range of Tinnermost was 28.6 to 32.0°C. The range of the upper clothing layers (Lupper) and total clothing mass (Mtotal) was 1.1 to 3.2 layers and 473 to 1659 g respectively. The range of Icl was 0.78 to 2.10 clo. 2) Post hoc analyses showed that analysis of Tinnermost produced the same results as for that of Icl. Likewise, the analysis of Lupper produced the same result as the analysis of the number of total layers (Ltotal) within an outfit. 3) Air temperature (ta) had positive relationships with Tchest and Tscapular and with Tinnermost but had inverse correlations with Icl, Mtotal, Lupper and Ltotal. Tchest, Tscapular, and Tinnermost increased as ta rose. 4) Icl had inverse relationships with Tchest and Tinnermost, but positive relationships with Mtotal, Lupper and Ltotal. Icl could be estimated by Mtotal, Lupper, and Tscapular using a multivariate linear regression model. 5) Lupper had positive relationships with Icl and Mtotal, but Llower did not. Subjects hardly changed Llower under environmental comfort conditions between March and October. This indicates that each of the Tchest, Mtotal, and Lupper was a factor in predicting Icl. Tinnermost might also be a more influential factor than the clothing microclimate temperature.

Relationship between adult height and body weight and risk of carotid atherosclerosis assessed in terms of carotid intima-media thickness: the Nagasaki Islands study.

Abstract: Previous studies have reported an inverse association between height and risk of cardiovascular disease. However, evidence is limited for the association between risk of atherosclerosis and height. Further, although the association between atherosclerosis and body mass index (BMI) is reportedly positive, there have been no reports of studies on associations between height and atherosclerosis in relation to BMI. We conducted a cross-sectional study of Japanese men aged 30 to 89 years undergoing general health check-ups. Of the 1,337 men, 312 were diagnosed with carotid atherosclerosis (carotid intima-media thickness (CIMT) ≥ 1.1 mm), but no significant association was found between height and carotid atherosclerosis for the entire study group. Stratification by BMI status of those analytical findings disclosed a significant inverse association between height and carotid atherosclerosis among overweight (BMI ≥ 25 kg/m2) but not among non-overweight (BMI < 25 kg/m2) men. The classical cardiovascular risk factors-adjusted odds ratio (OR) and 95% confidence interval (CI) of carotid atherosclerosis for an increment of one SD (standard deviation) in height (6.70 cm) were 0.71 (0.54 to 0.94) for overweight (BMI ≥ 25 kg/m2) and 1.05 (0.87 to 1.27) for non-overweight (BMI < 25 kg/m2) men. Independent from classical cardiovascular risk factors, height was found to be inversely associated with carotid atherosclerosis for overweight but not for non-overweight men.

Physiological relaxation induced by horticultural activity: transplanting work using flowering plants

Abstract: Background Despite increasing attention and a growing volume of research data, little physiological evidence is available on the benefits of horticultural activity and the different effects on individuals. Therefore, the aim of the present study was to investigate the physiological effects of horticultural activity and to examine how differences in personality alter these effects.

Association between alkaline phosphatase and hypertension in a rural Japanese population: the Nagasaki Islands study.

Abstract: Although serum alkaline phosphatase (ALP) levels have been associated with hypertension, and ALP is known as an enzyme affected by alcohol consumption, no study has been published on the associations between ALP and the risk of hypertension in relation to drinking status. We conducted a cross-sectional study of 2,681 participants (837 men and 1,846 women) aged 30 to 89 years undergoing a general health check-up to investigate the associations between ALP and hypertension in relation to drinking status. Of the 2,681 participants, 1,549 (514 men and 1,035 women) were diagnosed with hypertension. A sex difference was observed for the relationship between ALP and hypertension. While no significant association was observed for men, the association was significantly positive for women. The multivariable adjusted odds ratio and 95% coincidence interval (CI) of hypertension per increment of 1-log ALP were 0.95 (95% CI: 0.56 to 1.59) for men and 1.57 (95% CI: 1.07 to 2.33) for women. When this analysis was restricted to nondrinkers, a significantly elevated risk of hypertension was observed for men and remained significant for women; that is, 3.32 (95% CI: 1.38 to 8.02) for men and 1.68 (95% CI: 1.11 to 2.55) for women. ALP is associated with hypertension for both male and female nondrinkers, but not for drinkers. For analyses of associations between ALP and blood pressure, alcohol consumption should thus be considered a potential confounder.

Association between melanopsin gene polymorphism (I394T) and pupillary light reflex is dependent on light wavelength

Abstract: Background Our aim was to determine the association between melanopsin gene polymorphism and pupillary light reflex under diverse photic conditions, including different intensities and wavelengths.

Sexual dimorphism in digital dermatoglyphic traits among Sinhalese people in Sri Lanka.

Abstract: The purpose of this study was to evaluate gender-wise diversity of digital dermatoglyphic traits in a sample of Sinhalese people in Sri Lanka. Four thousand and thirty-four digital prints of 434 Sinhalese individuals (217 males and 217 females) were examined for their digital dermatoglyphic pattern distribution. The mean age for the entire group was 23.66 years (standard deviation = 4.93 years). The loop pattern is observed more frequently (n = 2,592, 59.72%) compared to whorl (n = 1,542, 35.53%) and arch (n = 206, 4.75%) in the Sinhalese population. Females (n = 1,274, 58.71%) have a more ulnar loop pattern than males (n = 1,231, 56.73%). The plain whorl pattern is observed more frequently in males (n = 560, 25.81%) compared to females (n = 514, 23.69%).The double loop pattern is observed more frequently on the right and left thumb (digit 1) of both males and females. Pattern intensity index, Dankmeijer index and Furuhata index are higher in males. Ulnar loop is the most frequently occurring digital dermatoglyphic pattern among the Sinhalese. All pattern indices are higher in males. To some extent, dermatoglyphic patterns of Sinhalese are similar to North Indians and other Caucasoid populations. Further studies with larger sample sizes are recommended to confirm our findings.

Association between body mass index and muscularity in healthy older Japanese women and men.

Abstract: Background: Body mass index (BMI), expressed as the ratio of body mass to height squared (kg/m 2 ), involves not only fat but also lean mass. The present study aimed to clarify how BMI is associated with total muscle mass (TMM) in older Japanese women and men. Findings: Using a B-mode ultrasound apparatus, muscle thickness was measured at nine sites (forearm, upper arm anterior and posterior, thigh anterior and posterior, lower leg anterior and posterior, abdomen, and subscapular) for 346 women (BMI 16.40 to 33.11 kg/m 2 ) and 286 men (BMI 16.86 to 31.18 kg/m 2 ) aged 60.0 to 79.5 yrs. TMM was estimated using the product of the sum of the muscle thicknesses at the nine sites with height as an independent variable. For both sexes, the estimated TMM relative to height squared was significantly correlated with BMI (r = 0.688, P<0.0001 for women; r = 0.696, P<0.0001 for men), but the percentage of the estimated TMM in body mass was not. Conclusion: These results indicate that, for older Japanese women and men, BMI is a simple and convenient index for assessing total muscularity.

Sustaining biological welfare for our future through consistent science

Abstract: Physiological anthropology presently covers a very broad range of human knowledge and engineering technologies. This study reviews scientific inconsistencies within a variety of areas: sitting posture; negative air ions; oxygen inhalation; alpha brain waves induced by music and ultrasound; 1/f fluctuations; the evaluation of feelings using surface electroencephalography; Kansei; universal design; and anti-stress issues. We found that the inconsistencies within these areas indicate the importance of integrative thinking and the need to maintain the perspective on the biological benefit to humanity. Analytical science divides human physiological functions into discrete details, although individuals comprise a unified collection of whole-body functions. Such disparate considerations contribute to the misunderstanding of physiological functions and the misevaluation of positive and negative values for humankind. Research related to human health will, in future, depend on the concept of maintaining physiological functions based on consistent science and on sustaining human health to maintain biological welfare in future generations.

Age-related, interindividual, and right/left differences in anterior-posterior foot pressure ratio in preschool children

Abstract: Background This study aimed to examine age-related, interindividual, and right/left differences in anterior-posterior foot pressure ratio in 764 preschool children (364 boys and 400 girls) aged 3.5-6.5 years.

Influence of maturation on anthropometry and body composition in Japanese junior high school students

Abstract: The purpose of this study was to examine maturity-related differences in anthropometry and body composition in Japanese youth within a single year Two hundred and ten Japanese youth aged from 13 to 1399 years participated in this study Their maturity status was assessed using a self-assessment of stage of pubic hair development Bioelectrical impedance analysis was used to estimate percent body fat and lean body mass (LBM) Muscle thickness of the anterior thigh, posterior lower leg and rectus abdominis muscles were measured by ultrasound For boys, height, body weight, and LBM in less mature groups were lower than that in more mature groups The maturity-related differences were still significant after adjusting for chronological age On the other hand, muscle thickness values in the lower extremity and abdomen differed among the groups at different stages of pubic hair development, whereas there was no maturity-related difference in the relative values corrected by LBM, except for those thickness values measured at the abdomen For girls, only the muscle thickness at the anterior thigh and muscle thickness relative to LBM1/3 at the posterior lower leg was significantly affected by maturity status, but significant maturity-related difference was not found after adjusting for chronological age At least for Japanese boys and girls aged 13 years, maturity status affected body size in boys, but not in girls, and the influence of maturation on the muscularity of the lower extremity and trunk muscles is less in both sexes

The relationship between consumption of tyrosine and phenylalanine as precursors of catecholamine at breakfast and the circadian typology and mental health in Japanese infants aged 2 to 5 years

Abstract: Background This study aims to examine the relationship between tyrosine and phenylalanine intake at breakfast as precursors of dopamine, and scores on the Torsvall-Akerstedt Diurnal Type Scale and of mental health in Japanese infants aged 2 to 5 years.

Asynchronous dentofacial development and dental crowding: a cross-sectional study in a contemporary sample of children in France.

Abstract: Background The causes of dental crowding are not fully understood, but it may result from an evolutionary trend towards reduced facial volume, without a proportional reduction in tooth sizes. Most previous studies conducted among modern humans have revealed a very low or non-existent correlation between tooth size and jaw size. Cross-comparison between dental age and facial skeletal age could help to provide better knowledge of the dynamic process of dental crowding. The primary objective of this research was to study the synchronism of dental maturation and skeletal facial growth in a sample of modern children living in France. The secondary objective was to assess the link between dentofacial asynchronism and dental crowding.

Ocular blood flow decreases during passive heat stress in resting humans

Abstract: Background Heat stress induces various physiological changes and so could influence ocular circulation. This study examined the effect of heat stress on ocular blood flow.

Adaptation changes in dynamic postural control and contingent negative variation during repeated transient forward translation in the elderly.

Abstract: Background Adaptation changes in postural control and contingent negative variation (CNV) for the elderly were investigated during repeated forward floor translation.

Visual information without thermal energy may induce thermoregulatory-like cardiovascular responses

Abstract: Human core body temperature is kept quasi-constant regardless of varying thermal environments. It is well known that physiological thermoregulatory systems are under the control of central and peripheral sensory organs that are sensitive to thermal energy. If these systems wrongly respond to non-thermal stimuli, it may disturb human homeostasis. Fifteen participants viewed video images evoking hot or cold impressions in a thermally constant environment. Cardiovascular indices were recorded during the experiments. Correlations between the ‘hot-cold’ impression scores and cardiovascular indices were calculated. The changes of heart rate, cardiac output, and total peripheral resistance were significantly correlated with the ‘hot-cold’ impression scores, and the tendencies were similar to those in actual thermal environments corresponding to the impressions. The present results suggest that visual information without any thermal energy can affect physiological thermoregulatory systems at least superficially. To avoid such ‘virtual’ environments disturbing human homeostasis, further study and more attention are needed.

The core interthreshold zone during exposure to red and blue light.

Abstract: Background: This study tested the hypothesis that the core interthreshold zone (CIZ) changes during exposure to red or blue light via the non-visual pathway, because it is known that light intensity affects the central nervous system. We conducted a series of human experiments with 5 or 10 male subjects in each experiment. Methods: The air temperature in the climatic chamber was maintained at 20 to 24°C. The subjects wore suits perfused with 25°C water at a rate of 600 cm 3 /min. They exercised on an ergometer at 50% of their maximum work rate for 10 to 15 minutes until sweating commenced, and then remained continuously seated without exercise until their oxygen uptake increased. The rectal temperature and skin temperatures at four sites were monitored using thermistors. The sweating rate was measured at the forehead with a sweat rate monitor. Oxygen uptake was monitored with a gas analyzer. The subjects were exposed to red or blue light at 500 lx and 1000 lx in both summer and winter. Results: The mean CIZs at 500 lx were 0.23 ± 0.16°C under red light and 0.20 ± 0.10°C under blue light in the summer, and 0.19 ± 0.20°C under red light and 0.26 ± 0.24°C under blue light in the winter. The CIZs at 1000 lx were 0.18 ± 0.14°C under red light and 0.15 ± 0.20°C under blue light in the summer, and 0.52 ± 0.18°C under red light and 0.71 ± 0.28°C under blue light in the winter. A significant difference (P <0.05) was observed in the CIZs between red and blue light at 1000 lx in the winter, and significant seasonal differences under red light (P <0.05) and blue light (P <0.01) were also observed at 1000 lx. Conclusions: The present study demonstrated that dynamic changes in the physiological effects of colors of light on autonomic functions via the non-visual pathway may be associated with the temperature regulation system.

Effect of maintaining neck flexion on anti-saccade reaction time: an investigation using transcranial magnetic stimulation to the frontal oculomotor field

Abstract: Background Reaction time for anti-saccade, in which the gaze is directed to the position opposite to an illuminated target, shortens during maintenance of neck flexion. The present study applied transcranial magnetic stimulation (TMS) to the frontal oculomotor field, and investigated the effect of maintaining neck flexion on information processing time in the anti-saccade neural pathway before the frontal oculomotor field.

Recent topics on the scope of physiological anthropology.

Abstract: Two years have passed since the Journal of Physiological Anthropology (JPA) adopted an open-access policy. The Editorial issued in 2012 provided an overview of the scope of the JPA[1] and reviewed the biological adaptations accomplished by Homo sapiens during the hunter-gatherer period, which spans most of human history, against the speed at which mankind has created artificial environments through the development of new technologies. In light of this, attention must be paid to how different the environmental pressures of today are compared with those of the past and what sort of impact this difference has on human adaptability. The discipline of physiological anthropology focuses on assessing exactly this human adaptability to the environment. The diversity and mechanisms of environmental adaptability, including techno-adaptability, are investigated from the perspective of physiological polytypism, whole-body coordination and functional potentiality, three major keywords in physiological anthropology [2]. Based on these keywords and the scope of the JPA, this article reviews selected studies published in the JPA in 2012. The major adaptation that enabled Homo sapiens to establish its unique abilities is bipedalism. This form of locomotion allowed for longer migration distances and improved visibility through providing a higher eye level, making hunting and gathering easier. However, an upright posture comes with the risks of having to increase blood pressure to pump blood even higher to the brain while venous return to the heart, which is situated relatively high within the body, tends to decrease against gravitational stress. Compared with quadrupeds, uprightness is a more challenging gravity-defying posture because high blood pressure must be maintained during any postural change. This is achieved via orthostatic cardiovascular responses, which are regulated by the autonomic nervous system and endocrine system as highly advanced coordinating reactions. However, today’s more sedentary lifestyle, due largely to modern transportation and office-based work, is thought to be weakening our orthostatic tolerance. Consequently, even in the field of physiological anthropology, many studies have investigated circulatory dynamics [3,4] and the orthostatic responses [5,6] in relation to postural change. In a recent JPA article by Ishibashi et al. [7], the authors proposed a novel method to evaluate orthostatic cardiovascular responses by using lower body negative pressure [7]. Compared with the conventional method, this method utilizes sinusoidal negative pressure to accurately simulate the blood shift to the lower body. By measuring the effect of the constant load component during oscillatory lower body negative pressure, it is possible to elucidate the frequency characteristics of each function involved in the regulation of orthostatic responses and to visualize temporal changes in the whole-body coordination of blood pressure regulation. This study falls within the scope of the JPA since the method can be used to investigate physiological polytypism in the relation between today’s living-related environmental factors and orthostatic tolerance in humans. Physiological anthropologists began the full-scale study of environmental adaptation in the second half of the 20th century [8,9]. In particular, the study of adaptation to thermal environments has a long history in Japan, as well as in the United States [10-12]. The International Biological Program (IBP) launched in 1964 was a large field study involving researchers from many countries, which was set up to investigate diverse environmental adaptations seen from an ecological point of view. In the late 1960s, Japan also started to investigate hypobaric and thermal adaptabilities using climate chambers in experimental studies. Some studies have been performed on thermal adaptability when reviewed in light of ‘functional potentiality’, one of the keywords of physiological anthropology. By defining heat tolerance as the ability to maintain body temperature under heat stress, these studies showed that heat tolerance varies among the residents of the United States, Europe, Africa and Asia [13]. Even among Asian populations, the ability to maintain body temperature differs between Japanese residing mainly in the temperate zone and Malaysians acclimatized to a tropical zone. Moreover, heat tolerance has been shown to improve in Malaysians who repeatedly perform physical work in a hot environment [14], demonstrating that even the inhabitants of tropical areas have sufficient functional potentiality remaining in the thermoregulatory mechanism. However, the functional potentiality of residents in tropical Asian countries is modified once they move into a temperate zone. In a comparison of Japanese men and south-east Asian men residing in Japan, Wijayanto et al. [15] revealed that south-east Asian men who had resided in Japan for a long time had an earlier sweating onset time and higher sweat rate than south-east Asian men who had resided in Japan for a shorter time, demonstrating the decay of acclimatization in the sweating response [15]. From the perspective of physiological anthropology, this study is interesting in that high heat tolerance acquired through long-term heat acclimatization to a tropical is decayed (an augmentation of functional potentiality) by residing in a temperate climate. In other words, the physiological polytypism observed among different communities is plastic to climatic conditions. It is known that adaptability to cold environments also exhibits physiological polytypism. For example, a previous study of physiological polytypism as a coordinated response to cold exposure showed that the Inuit people responded with an elevated metabolism, whereas the highland Quechua population of the Andes responded with increased thermal insulation. However, to fully understand the different phenotypic expressions, it is necessary to investigate environmental and nutritional factors; for example, whether consuming a high-calorie diet makes it possible to maintain an elevated metabolism in a given environment. Similarly, it is possible that in the study by Wijayanto et al. [15] environmental factors had more profound effects on heat adaptability than genetic factors. At present, it is unclear if and how genetic factors affect functional adaptability to the environment, and this is the current focus of study in physiological anthropology. Despite the human genome having been sequenced [16], physiological research on genetic adaptations has been delayed, partly because a relatively short time has elapsed since the official release of the International HapMap database [17,18] and because techniques and technologies are not yet sufficient to identify the link between functional phenotype and genes or genotype. Against this background, the JPA published an interesting article [19] on the involvement of mitochondrial DNA (mtDNA) polymorphism in cold adaptation from the viewpoint of human migration. The authors focused on mtDNA haplogroup D, the predominant haplogroup among Japanese, and investigated the association between physiological polytypism and seasonal variation in thermoregulation against a cold environment to reveal the involvement of mtDNA polymorphism in cold adaptation. This kind of experimental study often has a limited number of subjects and additional studies are needed before we can come to any conclusion on the influence of genetic factors. Nonetheless, the study is interesting in that thermoregulation against cold stress, especially in summer, was clearly different between the haplotype D and non-haplotype D groups. This study warrants attention because it is the first physiological anthropological study of its kind to demonstrate objectively the relation between physiological polytypisms and genetic factors. Here we have briefly introduced selected studies on physiological polytypism from the perspective of whole-body coordination and functional potentiality, both keywords in physiological anthropology, with the aim of helping JPA readers to understand the research aims and scope of the journal. It should be noted, however, that the JPA also publishes a large number of articles whose content has no direct association with these key concepts: we also welcome articles on the morphological and physiological characteristics of populations, in terms of age, sex and different regions, due to the variability of environmental adaptations in people today and those of the past. We look forward to receiving articles on various approaches for investigating environmental adaptability in mankind.

Higher ventilatory responses during and after passive walking-like leg movement in older individuals

Abstract: Minute ventilation ( ) during walking has been shown to be higher in older individuals than in young individuals, but the mechanisms underlying the higher ventilatory response is unclear. Central command and peripheral neural reflex are important neural control mechanisms underlying ventilatory response during exercise. Passive leg movement has been used to exclude the influence of central command due to the lack of voluntary activation of muscles. The aim of the present study was to compare the ventilatory response during and after passive walking-like leg movement (PWM) in young and older individuals. Eight young subjects (20 ± 2 years) and seven older subjects (70 ± 1 years) participated in this study. Subjects spent 7 minutes in a quiet standing (QS) position. Thereafter, they performed 14-minute rhythmic PWM at 1 Hz and this was followed by 7 minutes of QS. values during pre-PWM QS were calculated as 1-minute averages using data obtained between 5 and 6 minutes. values at pre-PWM QS in the young and older groups were 8.4 ± 2.1 and 7.5 ± 1.2 l/minute, respectively. values increased significantly at the first minute of PWM to 11.4 ± 2.2 and 10.4 ± 2.5 l/minute in the young and older groups, respectively (P <0.001). In the young group, at the last minute of PWM (9.2 ± 2.0 l/minute) was not significantly different from that at pre-PWM QS due to a decline in , whereas at the last minute of PWM in the older group (9.4 ± 2.2 l/minute) was still significantly higher (P <0.01). On the other hand, at the first minute of post-PWM QS (7.2 ± 1.8 l/minute) was significantly lower than that during pre-PWM QS in the young group (P <0.05) but not in the older group. Ventilatory response during and after PWM is higher in older individuals than in young individuals. This may be associated with a mechanism(s) other than central command. Our findings may explain part of the higher response while walking in older individuals.