Journal of Physiological Anthropology最新文献

Background: The specific microclimate of alpine waterfalls with high levels of ionized water aerosols has been suggested to trigger beneficial immunological and psychological effects. In the present three-armed randomized controlled clinical study, we focused on effects on (i) immunological reagibility, on (ii) physiological stress responses, and on (iii) stress-related psychological parameters.

Methods: People with moderate to high stress levels (n = 65) spent an active sojourn with daily hiking tours in the National Park Hohe Tauern (Großkirchheim, Austria). Half of the group was exposed to water aerosol of an alpine waterfall for 1 h/day (first arm, n = 33), whereas the other half spent the same time at a distant site (second arm, n = 32). A third arm (control, n = 26) had no intervention (except vaccination) and stayed at home, maintaining their usual lifestyle. The effect of the interventions on the immune system was tested by oral vaccination with an approved cholera vaccine and measuring specific salivary IgA antibody titers. Lung function was determined by peak expiratory flow measurement. Electric skin conductance, heart rate, and adaption of respiration rate were assessed as physiological stress parameters. Psychological stress-related parameters were analyzed by questionnaires and scales.

Results: Compared to the control group, both intervention groups showed improvement of the lung function and of most physiological stress test parameters. Analysis of the mucosal immune response revealed a waterfall-specific beneficial effect with elevated IgA titers in the waterfall group. In line with these results, exposure to waterfall revealed an additional benefit concerning psychological parameters such as subjective stress perception (measured via visual analog scale), the Global Severity Index (GSI), and the Positive Symptom Total (PST).

Conclusions: Our study provides new data, which strongly support an "added value" of exposure to waterfall microclimate when combined with a therapeutic sojourn at high altitude including regular physical activity.

Background: Flight controllers of the International Space Station (ISS) are engaged in shift work to provide 24-h coverage to support ISS systems. The purpose of this study was to investigate the prevalence and associated factors of shift work sleep disorder (SWSD) among Japanese ISS flight controllers.

Methods: A questionnaire study was conducted using the Standard Shiftwork Index to evaluate sleep-related problems and possible associated variables. Among 52 respondents out of 73 flight controllers, 30 subjects were identified as night shift workers who worked 3 or more night shifts per month. Those night shift workers who answered "almost always" to questions about experiencing insomnia or excessive sleepiness in any case of work shifts and days off were classified as having SWSD. Additionally, 7 night shift workers participated in supplemental wrist actigraphy data collection for 7 to 8 days including 3 to 4 days of consecutive night shifts.

Results: Fourteen of 30 night shift workers were classified as having SWSD. Significant group differences were observed where the SWSD group felt that night shift work was harder and reported more frequent insomniac symptoms after a night shift. However, no other variables demonstrated remarkable differences between groups. Actigraphy results characterized 5 subjects reporting better perceived adaptation as having regular daytime sleep, for 6 to 9 h in total, between consecutive night shifts. On the other hand, 2 subjects reporting perceived maladaptation revealed different sleep patterns, with longer daytime sleep and large day-to-day variation in daytime sleep between consecutive night shifts, respectively.

Conclusions: As the tasks for flight control require high levels of alertness and cognitive function, several characteristics, namely shift-working schedule (2 to 4 consecutive night shifts), very short break time (5 to 10 min/h) during work shifts, and cooperative work with onboard astronauts during the evening/night shift, accounted for increasing workloads especially in the case of night shifts, resulting in higher or equal prevalence of SWSD to that among other shift-working populations. Further studies are required to collect more actigraphy data and examine the possibility of interventions to improve SWSD.

Previous research has shown an exaggeration in exercise hyperpnea 2 days after eccentric exercise (ECC). Enhancement in central command has been suggested as one candidate to account for this effect given that ECC-induced neuromuscular dysfunction increases relative exercise intensity, thus resulting in reinforcement of effort sense. The purpose of this study was, therefore, to elucidate whether the degree of alteration in effort sense caused by ECC affects exercise hyperpnea. Ten subjects performed 20-s single-arm extension-flexion exercises with weight strapped to the wrist, and ventilatory response was measured before (Pre) and 2 days after ECC (D2). Relative exercise intensity at Pre was 5 % of maximal voluntary contraction (MVC) of Pre, whereas that at D2 was 9 % MVC of D2 because of decline in muscle strength. Ventilatory responses were significantly exaggerated at D2 with a significant increase in effort sense. Although effort sense was significantly reduced during exercise at D2 when wrist weight was subtracted to match relative exercise intensity at Pre (5 % MVC of D2), ventilatory responses were still significantly higher than those of Pre. After the disappearance of post-ECC muscle damage, subjects performed the same exercise with weight added (9 % MVC of Pre) so that effort was equalized to match that of D2; however, no significant increase in ventilatory response was detected. The fact that the extent of change in effort sense caused by ECC-induced neuromuscular dysfunction did not affect ventilatory response at the onset of exercise after ECC may suggest that the exaggeration of ventilatory response after ECC is caused by mechanisms other than alteration of the central command.

Background: Real-time ultrasound imaging is a valid method in the field of rehabilitation. The ultrasound imaging allows direct visualization for real-time study of the muscles as they contract over the time. Measuring of the size of each abdominal muscle in relation to the others provides useful information about the differences in structure, as well as data on trunk muscle activation patterns. The purpose of this study was to assess the size and symmetry of the abdominal muscles at rest in healthy adults and to provide a reference range of absolute abdominal muscle size in a relatively large population.

Method: A total 156 healthy subjects with the age range of 18-44 years were randomly recruited. The thickness of internal oblique, external oblique, transverse abdominis, and rectus abdominis muscles was measured at rest on both right and left sides using ultrasound. Independent t test was used to compare the mean thickness of each abdominal muscle between males and females. Differences on side-to-side thicknesses were assessed using paired t test. The association between abdominal muscle thicknesses with gender and anthropometric variables was examined using the Pearson correlation coefficient.

Results: A normal pattern of increasing order of mean abdominal muscle thickness was found in both genders at both right and left sides: transverse abdominis < external oblique < internal oblique < rectus abdominis. There was a significant difference on the size of transverse abdominis, internal oblique, and external oblique muscles between right and left sides in both genders. Males had significantly thicker abdominal muscles than females. Age was significantly correlated with the thickness of internal oblique, external oblique, and rectus abdominis muscles. Body mass index was also positively correlated with muscle thickness of rectus abdominis and external oblique.

Conclusions: The results provide a normal reference range for the abdominal muscles in healthy subjects and may be used as an index to find out abnormalities and also to evaluate the effectiveness of different interventions.

Background: Insensible body mass loss (IBL) from the human body continuously occurs, which is an important component in body heat exchange. The purpose of this study was to examine the relevance of IBL to anthropometric characteristics and self-identified thermal tolerance.

Methods: A total of 289 healthy young Korean males were chosen and sorted into the following three groups: heat tolerable only (HTO, N = 79), cold tolerable only (CTO, N = 104), neither heat nor cold tolerable (NHC, N = 106). They weighed before and after a 30-min rest under lightly clothed condition at an air temperature of 23 ± 1 °C with a relative humidity 55 ± 5 %RH.

Results: (1) The IBL of 289 males had a mean of 90 ± 75 g h(-1) (48 ± 40 g h(-1) m(-2)); (2) No significant difference in IBL among the three groups were found; (3) Significant differences in body weight and body mass index (BMI) among three groups were found (P < 0.05), but insignificance was found for height (P = 0.726) or body surface area (P = 0.059); (4) CTO was approximately 4.1 kg heavier in body weight (P < 0.05) and higher in BMI (P < 0.01) than in HTO; (5) Only for the group CTO, IBL (g h(-1)) showed a positive relationship to BMI (P < 0.05, R (2) = 0.056), but there was no relationship between IBL and body surface area.

Conclusions: For healthy young males within normal anthropometric ranges in Korea, IBL was positively related to BMI, and individuals with greater BMI showed greater self-identified cold tolerance, but no direct relationship was found between IBL and self-identified cold tolerance. This suggests that body physique (e.g., BMI) could be an explanatory factor between insensible body heat loss and subjective cognition on cold tolerance.

Background: Adaptation changes in postural muscle activity and anticipatory attention were investigated with the ankle joint fixed to change postural control strategies during transient floor translation.

Methods: For 15 healthy young adults, 40 transient floor translations (S2) in the anterior direction were applied 2 s after an auditory warning signal (S1), under conditions with or without fixation of the ankle. Activity of the frontal postural muscles (tibialis anterior (TA), rectus femoris (RF), rectus abdominis) and contingent negative variation (CNV, brain potential) were analyzed for 20 trials each of the early and latter halves under each fixation condition.

Results: With fixation, peak amplitude of muscle activity after S2 was significantly decreased in TA and increased in RF. These muscles showed marked adaptive decreases. The early component of CNV reduced with adaptation, particularly under fixation condition. Only in RF, background activity increased just before S2, with adaptation under fixation. A significant correlation was found between timings of CNV peak and RF activation just before S2 only after adaptation under fixation.

Conclusion: These results suggest that the main activation muscle changes from TA to RF with fixation. Under such condition, attention would be focused on the knee with adaptation, and the need for heightening attention in the early stage may have declined. Correspondingly, the timing to heighten stiffness of the RF became later, and attention would have been paid to RF activation just before S2.

Background: Seasonal variations in physiology and behavior have frequently been reported. Light is the major zeitgeber for synchronizing internal circadian rhythms with the external solar day. Non-image forming effects of light radiation, for example, phase resetting of the circadian rhythms, melatonin suppression, and acute alerting effects, depend on several characteristics of the light exposure including intensity, timing and duration, spectral composition and previous light exposure, or light history. The aim of the present study was to report on the natural pattern of diurnal and seasonal light exposure and to examine seasonal variations in the circadian change of melatonin and cortisol concentrations for a group of Swedish office workers.

Methods: Fifteen subjects participated in a field study that was carried out in the south of Sweden. Ambulatory equipment was used for monthly measurements of the daily exposure to light radiation across the year. The measurements included illuminance and irradiance. The subjects collected saliva samples every 4 h during 1 day of the monthly measuring period.

Results: The results showed that there were large seasonal differences in daily amount of light exposure across the year. Seasonal differences were observed during the time periods 04:00-08:00, 08:00-12:00, 12:00-16:00, 16:00-20:00, and 20:00-24:00. Moreover, there were seasonal differences regarding the exposure pattern. The subjects were to a larger extent exposed to light in the afternoon/evening in the summer. During the winter, spring, and autumn, the subjects received much of the daily light exposure in the morning and early afternoon. Regarding melatonin, a seasonal variation was observed with a larger peak level during the winter and higher levels in the morning at 07:00.

Conclusions: This study adds to the results from other naturalistic studies by reporting on the diurnal and seasonal light exposure patterns for a group living at a northern latitude of 56° N, with large annual variations in photoperiod length. It seems to be seasonal variation in the lighting conditions, both concerning intensities as well as regarding the pattern of the light exposure to which people living at high latitudes are exposed which may result in seasonal variation in the circadian profile of melatonin.

Background: Very little is known about the neural circuitry underlying anger processing among alcoholics. The purpose of this study was to examine the altered brain activity of alcoholic individuals during transient anger emotion.

Methods: Using functional magnetic resonance imaging (fMRI), 18 male patients diagnosed with alcohol dependence in an inpatient alcohol treatment facility and 16 social drinkers with similar demographics were scanned during the viewing of anger-provoking film clips.

Results: While there was no significant difference in the level of experienced anger between alcohol-dependent patients and non-alcoholic controls, significantly greater activation was observed in the bilateral dorsal anterior cingulate cortex (dACC) and the right precentral gyrus among alcoholic patients compared to the normal controls.

Conclusions: In summary, specific brain regions were identified that are associated with anger among patients with alcohol dependency.

Background: This study compared the effects of barefoot policy, a policy instructing preschool children to go without shoes, on untouched-toes, which do not touch the ground while standing normally, of preschool children attending kindergartens that follow this rule, to preschooler in kindergartens where they must wear shoes, i.e., no-barefoot policy.

Methods: The study used longitudinal data from measurements taken 2 years apart of the amount of times. The subjects were 59 children (34 boys and 25 girls) who went to a kindergarten that followed barefoot policy and 179 children (103 boys and 76 girls) who went to a kindergarten that did not follow barefoot policy. Images were taken of the contact surface area of the soles of the children's feet by having them stand on the measurement device with their bare feet.

Results: The number of untouched-toes in children participating in the study was determined from the pictures. In boys who attended kindergartens following barefoot policy, the ratio of the children without untouched-toes significantly increased for 2 years of childhood (35.3-64.7 %). The number of untouched-toes were significantly fewer in boys from kindergartens following barefoot policy than in boys from kindergartens not following the policy, and the magnitude of the difference grew for the two study years (ES: 0.41-0.63). In girls, there were no significant differences between the two groups in the ratio of girls without untouched-toes and the number of untouched-toes.

Conclusions: In conclusion, the ground contact of the toes becomes better for boys in kindergarten with a barefoot policy. The results were inconclusive with regard to girls, and other factors may need to be examined. In the future, it will be necessary to increase the number of the subjects and perform detailed examinations.