Journal of Physiological Anthropology最新文献

The recent Journal of Physiological Anthropology article on polycythemia among Tibetan highlanders (Arima et al., J Physiol Anthropol 43:25, 2024) piqued our interest because we collected similar data in the same Nepali village in Upper Mustang two years later with notably different results (Cho et al., Evol Med Public Health 2017:82-96, 2017; Ye et al., Proc Natl Acad Sci U S A 121:e2403309121, 2024). Arima et al report high prevalences of chronic disease and conclude that Tsarang villagers have poor health. Here, we describe our relevant findings to show that authors' definitions and other research design elements can yield different population health implications. Our study sampled ethnic Tibetan Upper Mustang women 39 Years and older in 2012 who had been married or pregnant and were lifelong residents of this village at 3500m. At our 2019 follow-up study, the women were 46 Years and older. Fifty-five of the 64 eligible Tsarang residents (85%) participated in 2019 study designed to examine the influences of genes and physiology on reproductive success. Arima et al. sampled all Tsarang residents 18 or older in 2017, therefore, our studies include many of the same women in their mid-40s and older. Arima et al reported that 12% of the sample were polycythemic, whereas we found none; they reported 26% obesity whereas we found none; they showed 17% of the sample had hypertension, whereas we found 27%. Factors that may account for the differences in estimates of chronic disease prevalence in Tsarang include age differences in the samples, a wider age range in the currently reported sample, undefined cut-off values for disease categories, while we applied and reported chronic diseases using standard definitions. Because our study did not replicate the findings of Arima et al., we caution against concluding that women in Tsarang have alarming rates of obesity, polycythemia, and hypoxia. Our studies agree that high blood pressure is a public health problem among women in Tsarang. Future use of clear definitions of disease categories will help establish a common understanding of a population's health.

Background: Cold-induced vasodilation (CIVD) reduces the risk of local cold injuries. There are obvious differences in CIVD characteristics among different ethnic groups. This study aimed to compare cold tolerance manifested through CIVD responses in indigenous Tibetans and Han residents in Tibet.

Methods: A total of 12 Tibetans and 10 Han individuals (residence duration at high altitude > 5 years) from high altitudes were recruited in the study. The CIVD test was performed by immersing the participants' middle finger of the non-dominant hand in cold water (0 ℃) for 30 min followed by recovery for 10 min at a temperature of 25 ± 1 ℃. During the CIVD tests, the participants provided perceptual responses for the immersed hand every 5 min. The participants completed their baseline questionnaires and physiological assessments before the start of the CIVD test, and they completed their hematological tests the following morning.

Results: Compared with Hans at high altitude, Tibetans had higher minimum temperature (T_min), maximum temperature (T_max), and Resistance Index for Frostbite (RIF) scores (p < 0.05), and warmer perceptual responses (p < 0.05). We found that red blood cell (RBC) count, hemoglobin (HGB) and hematocrit (HCT) were positively correlated with onset time (Δt_onset), peak time (Δt_peak), frequency of CIVD waves (CIVD_waves), and negatively correlated with T_min, T_max, mean finger temperature (T_mean) in the general population (p < 0.05), whereas these correlations were not observed in the Tibetan and Han populations (p > 0.05). However, the basophil percentage (BAS%), neutrophil percentage (NEU%) and γ-glutamyl transpeptidase (GGT) levels (p < 0.05) correlated with the RIF score in Han population.

Conclusion: Compared with Hans at high altitude, indigenous Tibetans demonstrated superior local cold resistance phenotypes in vasomotor regulation, evidenced by their distinct CIVD and perceptual responses. Hematological and biochemical parameters, erythrocytosis is a critical determinant of local cold tolerance at high altitude in the general population. BAS%, NEU%, and GGT are related to local cold tolerance in Han residents.

Purpose: There are no previous reports investigating the effects of different set numbers in low-intensity resistance exercise with slow movement and tonic force generation (LST) on muscle fatigue using surface electromyography (sEMG). This study aimed to examine muscle fatigue induced by one set and three sets of LST and to compare the impact of set differences on muscle activity by comparing LST with traditional high-intensity resistance exercise (TRAD).

Methods: Twenty-three healthy male students participated in this study. After 1RM testing in each leg was completed, participants were randomly assigned to either a group performing one set of exercises (n = 10) or a group performing three sets (n = 13). Each participant performed the LST protocol (50% 1RM) and the TRAD protocol (80% 1RM) with single leg extension until failure. The LST protocol consisted of a 3-s concentric, a 1-s isometric, and a 3-s eccentric phase. In contrast, the TRAD protocol consisted of a 1-s concentric, a 1-s eccentric, and a 1-s rest phase. For the three-set group, a 2-min rest interval was provided between sets. The outcome measures included maximal isometric knee extension torque (MVC) before and after exercise, root mean square (RMS), and mean power frequency (MPF) values recorded during the exercises.

Results: No significant differences in MVC were observed between the type of exercise or the number of sets. Similarly, no significant differences in the RMS during the exercise were observed across exercise types or number of sets. On the other hand, with the significant interaction of MPF (p = 0.001, η_p² = 0.399), there was a significant difference in three sets of LST compared to one set of LST (p = 0.012, d = 1.16) and three sets of TRAD (p < 0.001, d = 0.93).

Conclusion: Our findings suggest that performing three sets of LST induces significant muscle fatigue. Therefore, we speculate that performing three sets of LST may lead to the accumulation of metabolic stress and thereby cause muscle fatigue.

Introduction: This study aimed to explore the effects of a single mild-dose, acute hyperbaric oxygen (HBO) intervention (1.3 ATA, 100% oxygen, 60 min) on aerobic endurance, cardiac function, pulmonary function, and autonomic nervous system balance in healthy young men.

Methods: Using a randomized crossover design, 14 participants received both the HBO intervention and the control condition (seated rest). For each condition, heart rate variability (HRV), cardiac function, and pulmonary function were assessed before and after the intervention, while aerobic endurance indicators-such as peak oxygen uptake (VO₂peak) and time to exhaustion (TTE)-were measured once following each condition.

Results: HBO significantly decreased resting heart rate (from 63.64 ± 7.75 to 58.79 ± 7.29 bpm, Δ = -7.23%, p = 0.009), with a significant main effect of time (F(1,13) = 7.657, p = 0.016, η²ₚ = 0.371) and a significant time × condition interaction effect (F(1,13) = 4.51, p = 0.048, η²ₚ = 0.268). Root mean square of successive differences (RMSSD) increased from 44.50 [24.50, 59.75] to 54.00 [35.50, 67.50] (Z = 2.261, p = 0.024, r = - 0.604), and standard deviation of successive differences (SDSD) increased from 55.50 [31.75, 76.50] to 71.00 [55.75, 87.75] (Z = 2.701, p = 0.007, r = - 0.722). Both parameters also demonstrated significant differences in condition comparisons (RMSSD: Z = - 2.826, p = 0.005, r = - 0.755; SDSD: Z = - 2.796, p = 0.005, r = - 0.747). No significant changes were observed in aerobic endurance, pulmonary function, or other cardiac function parameters.

Conclusion: A single mild-dose, acute HBO intervention can significantly improve resting heart rate and enhance short-term HRV parameters, suggesting a beneficial effect on parasympathetic activity. However, it does not directly enhance aerobic endurance, and long-term interventions or combined training may be needed to realize its potential benefits.

Background: Excessive fatigue, sleep deprivation, and poor intershift recovery after night shifts are associated with an increased risk of traffic accidents and maladaptive chronic fatigue. However, little is known about whether taking a nap or break immediately after a night shift improves fatigue recovery and sleep among nurses. This study aimed to examine the effects of taking a 30-min nap or break immediately after a 16-h night shift on fatigue recovery and sleep episodes among nurses.

Methods: A quasi-experimental crossover study was conducted with 62 nurses who worked 16-h night shifts. Nurses were randomly assigned to two condition sequences (AB or BA): (A) intervention (the nurses took a 30-min nap or break in a nap environment control system after a night shift) and (B) control (the nurses went home as usual after a night shift). Fatigue was measured immediately after the night shift, after taking a nap or break, and after getting up from nighttime sleep on the day after the night shift. Sleep episodes were assessed using a wearable device. Outcomes were compared between the two conditions.

Results: In the intervention condition, fatigue immediately after the night shift was significantly reduced by taking a nap or break, with a large effect size. Recovery from "local pain or dullness," one of the symptoms of work-related fatigue, was significantly higher in the intervention than control condition. Compared to the control condition, the intervention condition significantly delayed the timing of the first sleep episode, whereas no significant differences were observed in the main sleep parameters.

Conclusions: Taking a nap or break immediately after the night shift could be a countermeasure to address fatigue/sleep-related problems among nurses. For nursing managers, encouraging nurses to take a nap or break immediately after the night shift could be a viable option in comprehensive fatigue risk management. Therefore, appropriate napping environments should be installed in clinical settings.

Trial registration: UMIN000038444 (date of registration: 30 Oct 2019).

Background: Stunting in early life is associated with increased morbidity and mortality among children under 5, as well as impaired health and educational and economic performance in later life. However, few studies have investigated risk factors associated with stunting using nationwide representative data in Lao People's Democratic Republic (Lao PDR). The present study investigated the association of the household wealth index with stunting among children under 5 in Lao PDR using data from the Lao Social Indicator Survey II (LSIS II).

Methods: The present cross-sectional study used secondary data from the LSIS II in 2017. The survey used multi-stage stratified cluster sampling, covering all 18 provinces with 1170 clusters (village), resulting in a sample size of 23,400 households. The final analysis included 11,339 (weighted) children under 5. Multivariable logistic regression analysis was performed to examine associated factors.

Results: Risk factors significantly associated with stunting were no health insurance coverage, minority ethnic groups, having ≥ 7 family members in the household, a poor household wealth index, having ≥ 2 children under 5 in the household, living in rural areas, living in the southern part, and low birth weight. Among them, household wealth index was significantly associated with stunting, independent of other socioeconomic risk factors.

Conclusions: The household wealth index was significantly associated with child stunting. Given the high prevalence of stunting in Lao PDR, there may be a need for the government to implement programs to improve household socioeconomic status in order to address stunting in Lao PDR.

Background: Vitamin D deficiency is highly prevalent among Japanese female university students. Vitamin D deficiency is associated with physical and mental health problems, including sleep disorders. This study aimed to clarify the relationship between vitamin D deficiency and sleep and mental health problems among Japanese female university students.

Methods: Participants were 224 female university students. Blood levels of 25-hydroxyvitamin D [25(OH)D] were measured using liquid chromatography-tandem mass spectrometry for vitamin D assessment. Mental health was assessed using the K6. Sleep-wake status as a factor related to mental health was assessed using the Athens Insomnia Scale (AIS) and Munich ChronoType Questionnaire. Loneliness was assessed using the Three-Item Loneliness Scale. Factors predicting mental health problems with a K6 score ≥ 5 were explored using the Mann-Whitney U test, Fisher's exact probability test, and classification and regression tree (CART) analysis.

Results: The median (interquartile range) serum 25(OH)D concentration was 14.5 (11.8-18.3) ng/mL. Of the participants, 80.8% had vitamin D deficiency (25(OH)D < 20 ng/mL), and 26.3% had severe vitamin D deficiency (25(OH)D < 12 ng/mL). In total, 41.1% had mental health problems with a K6 score of ≥ 5. Although there was no significant association between vitamin D deficiency and sleep-wake problems, vitamin D deficiency was more prevalent among those with K6 scores ≥ 5 (P = 0.02). Compared to those with K6 < 5, those with K6 ≥ 5 had significantly higher Loneliness and AIS scores (P < 0.001), greater social jetlag (P = 0.03), shorter sleep duration on weekdays (P = 0.03), and lower serum 25(OH)D concentration (P = 0.02). In the CART analysis, the algorithm was set in the order of Loneliness score ≥ 6, AIS score ≥ 7, social jetlag ≥ 150 min, and serum 25(OH)D concentration < 14 ng/mL, and the target accuracy (95% confidence interval: CI) was 76.5 (70.3-81.9)%, and sensitivity and specificity (95% CI) were 62.2 (51.4-72.2)% and 86.3 (79.2-91.6)%, respectively.

Conclusions: Loneliness, insomnia symptoms, social jetlag, and vitamin D deficiency were associated with mental health problems among Japanese female university students.

Background: Perceptual load is a major determinant of visual attentional selection patterns, and dynamic stimuli are salient bottom-up distractors. The present study investigated how dynamic stimuli, presented under different perceptual loads, impact the process of visual attentional selection.

Methods: Fourteen participants (8 females and 6 males) were measured on task performance (reaction time and correctness) and event-related potentials while searching for visual exploratory task in a perceptual load paradigm.

Results: In terms of behavioral performance, longer reaction times were required for the visual exploratory task under high perceptual load, whereas a trend suggestive of attentional capture reversal emerged under low perceptual load. Regarding ERP components, the P1 amplitude was more positive in the response to dynamic stimuli, while the N1 amplitude was more negative when dynamic stimuli were absent. The P3 amplitude was more positive in the presence of dynamic stimuli than in their absence and was also more positive under low perceptual load than under high perceptual load.

Conclusions: This study found that N1 and P1 components were more sensitive to dynamic stimuli and insensitive to perceptual loads, while the P3 component effectively assessed both perceptual loads and dynamic stimuli. These variations reflect differential attentional allocation. Based on these findings, adapting interface displays according to gaze direction and perceptual load level can inform the design of user interfaces, such as those in navigation systems, educational materials, and assistive devices.

Trial registration: This study was approved by the Ethics Committee of Chiba University Graduate School of Engineering (acceptance number: R4-20, Acceptance date: March 22, 2023).

Background: Sleep deprivation and irregular sleep patterns can adversely affect physical and mental health. The COVID-19 pandemic presented a naturalistic opportunity to examine how reduced social time restrictions influence sleep behavior. This study aimed to investigate both group-level and individual-level changes in sleep patterns among Japanese university students before and during the pandemic and to explore how individual characteristics may contribute to these changes.

Methods: Twenty-two female university students wore waist-worn actigraphy devices for approximately 16 weeks in both 2019 and 2020. Objective sleep data were collected alongside questionnaire assessments of chronotype, personality traits, and subjective sleep feeling.

Results: In total, 4,432 valid days of actigraphy data were analyzed. Compared with the pre-pandemic year, sleep timing was delayed by approximately 20 min for bed-in time and 40 min for bed-out time in 2020. Time in bed (TIB) increased by about 20 min, while total sleep time (TST) remained largely unchanged. Sleep efficiency declined, but subjective sleep feeling remained stable. Individual-level analyses revealed substantial variability: 9 of 22 participants showed significant changes in TST, with both increases and decreases observed. Increased TIB was associated with later bed-out time, shorter baseline sleep duration, and lower neuroticism. A later bed-in time was associated with reduced TST.

Conclusions: These findings suggest that while social time restrictions can influence sleep timing and duration, the effects vary considerably across individuals. Earlier bedtimes may be more effective than simply extending TIB in promoting adequate sleep. Furthermore, individual characteristics such as personality traits may play a role in sleep adaptation under changing social contexts. Given the diversity of responses observed, both group- and individual-level perspectives are essential for understanding sleep behavior in real-world settings.

Background: Metabolic syndrome (MetS) is a cluster of metabolic abnormalities that increase the risk of cardiovascular disease and type 2 diabetes. High-sensitivity C-reactive protein (hs-CRP) is a biomarker of systemic inflammation, but its relationship with MetS and its components remains unclear. This study investigates the association between hs-CRP and MetS in a representative Korean population.

Methods: Using data from the 2022 Korea National Health and Nutrition Examination Survey (KNHANES), we analyzed 4,823 adults. MetS was defined according to revised NCEP-ATP III criteria. Multivariate analyses were conducted, adjusting for confounders such as sex, age, income, education, smoking, alcohol consumption, physical activity, and waist circumference.

Results: Among the study population, 1,784 participants (37.0%) were diagnosed with MetS. hs-CRP levels were significantly higher in individuals with MetS (1.06 mg/L vs. 0.79 mg/L, p < 0.001) and increased with the number of MetS components (p for trend < 0.001). Significant associations were observed between hs-CRP and all MetS components. However, after adjusting for waist circumference, these associations lost statistical significance.

Conclusion: This study confirms a strong association between hs-CRP and MetS, primarily influenced by central obesity. The findings highlight abdominal obesity as a key contributor to systemic inflammation in MetS. Further longitudinal studies are needed to explore the causal relationship and underlying mechanisms.