Journal of Physiological Anthropology最新文献

Background: Having higher muscle mass in early adulthood is an important factor in preventing sarcopenia. However, university students undergo lifestyle changes compared to their high school years, which may lead to changes in body composition, such as an increase in body fat and a decrease in muscle mass. The study aimed to investigate the association between body composition and lifestyle behaviors, including chronotype, among Japanese female university students, due to the prevalence of underweight among young females in the country.

Methods: The physical activity level (PAL), daily dietary intake status, morningness-eveningness questionnaire (MEQ) score, and body composition of 230 students were assessed in this cross-sectional study. Body composition was measured using a multifrequency bioelectrical impedance analyzer, and body mass index (BMI), body fat percentage (%BF), and skeletal muscle mass index (SMI) were determined.

Results: Individuals who were evening type (ET) had a higher %BF and lower SMI than those who were non-ET, but no differences in body weight or BMI were found. Although ET individuals had lower total energy intake, protein intake, and PALs than non-ETs, the differences were small. However, multiple regression analyses showed that SMI was significantly positively associated with MEQ and PAL, and %BF was significantly negatively associated with MEQ and PAL.

Conclusion: These results suggest that female university students with lateness of chronotype and low physical activity have a body composition imbalance resulting in higher body fat and lower muscle mass. Therefore, young females may need to take chronotype-specific measures (especially ET individuals) to help them maintain an appropriate body composition.

Background: Local alternating heat and cold stimulation as an alternative to contrast bath may cause intermittent vasoconstriction and vasodilation, inducing a vascular pumping effect and consequently promoting increased tissue blood flow and oxygenation. This study aimed to examine the effects of local alternating heat and cold stimulation, using a wearable thermal device, on the hemodynamics of fatigued muscle tissue and autonomic nervous activity.

Methods: Twenty healthy individuals experienced fatigue in the periarticular muscles of the shoulder joint due to a typing task. Local alternating heat and cold stimulations were then applied to the upper trapezius muscle. Muscle hardness was measured using a muscle hardness meter, and muscle tissue hemodynamics and oxygenation were evaluated using near-infrared spectroscopy before and after the stimulation. Autonomic nervous activity was also evaluated using heart rate variability.

Results: Alternating heat and cold stimulation decreased muscle hardness of the fatigued trapezius muscle from 1.38 ± 0.15 to 1.31 ± 0.14 N (P < 0.01). The concentration of total hemoglobin in the trapezius muscle tissue increased from - 0.21 ± 1.36 to 2.29 ± 3.42 µmol/l (P < 0.01), and the tissue hemoglobin oxygen saturation also increased from 70.1 ± 5.4 to 71.1 ± 6.0% (P < 0.05). Additionally, the heart rate variability parameter, which is an index of sympathetic nervous activity, increased from 3.82 ± 2.96 to 6.86 ± 3.49 (P < 0.01). A correlation was found between increased tissue hemoglobin oxygen saturation and increased parameters of sympathetic nervous activity (r = 0.50, P < 0.05).

Conclusions: Local alternating heat and cold stimulation affected the hemodynamic response in fatigued muscle tissue and autonomic nervous activity. This stimulation is more efficient than conventional contrast baths in terms of mobility and temperature control and has potential as a new versatile therapeutic intervention for muscle fatigue.

Trial registration: UMIN-CTR (UMIN000040087: registered on April 7, 2020, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000045710 . UMIN000040620: registered on June 1, 2020, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000046359 ).

Nutritional anthropology is the study of human subsistence, diet and nutrition in comparative social and evolutionary perspective. Many factors influence the nutritional health and well-being of populations, including evolutionary, ecological, social, cultural and historical ones. Most usually, biocultural approaches are used in nutritional anthropology, incorporating methods and theory from social science as well as nutritional and evolutionary science. This review describes approaches used in the nutritional anthropology of past and present-day societies. Issues of concern for nutritional anthropology in the world now include: understanding how undernutrition and food insecurity are produced at local, regional and international levels; how food systems are constructed using social, biological and biocultural perspectives; and obesity from a biocultural viewpoint. By critiquing framings of present-day diet in an evolutionary context, nutritional anthropology asks 'what should be eaten?', rather than 'what can be eaten?', and 'how cheaply can people be fed?'.

Background: Age and reduction in performed physical activity cause physiological changes that include an increase in body fat (BF) and visceral fat (VF) during aging. These parameters, together with increased body mass (BM), are some of the risk factors of several noninfectious diseases. However, changes in body composition can be influenced by regular physical activity. Running is a suitable, accessible, and the most effective physical activity cultivating people. The objective of this study is to investigate the effects of long-term, regular PA, specifically recreational running, on changes in body composition among recreational adult runners covering a weekly distance of at least 10 km, compared with inactive adult individuals within the same age bracket.

Methods: The study included 1296 runners and inactive individuals (691 male and 605 female), divided into 5 age groups: 18-25, 26-35, 36-45, 46-55, and 56-65 years. Runners are as follows: ran ≥ 10 km/week, and inactive is as follows: did not follow the WHO 2020 physical activity recommendations. The measured parameters included BM, BF, and VF. To check statistical significance, the Mann-Whitney U-test was used. Practical significance was assessed using the effect of size.

Results: All age groups of runners were selected to include individuals who run at least 10 km per week. In fact, they ran, on average, from 21.6 to 31.4 km per week in relation to age and showed significantly lower values of BM, BMI, BF, and VF (p < 0.05) than inactive individuals. Exceptions included insignificant differences (p > 0.05) in BM and BMI in males in the age category of 18-25 and in females in the age category of 18-25 and 26-35.

Conclusion: The selected runners had to run at least 10 km per week. Their actual average volume was significantly higher (from 21.6 to 31.4 km/week), and the results showed that it could lead to significantly better body composition values. It may lead to significant changes in body mass, body fat, and visceral fat. It may meet the contemporary societal expectations for physical activities that are both achievable and effective at the lowest possible volume.

Background: Older men often experience nocturnal urination difficulties, reflected by diurnal differences in maximum urine flow (Qmax). Since lower urinary tract symptoms and pathological comorbidities are frequent in older men, it remains unclear whether this diurnal variation is a physiological or pathological phenomenon. Our aim was to quantify the diurnal variability of Qmax in healthy young participants under varying daylight conditions in a stable environment to discern potential underlying causes of nocturnal urination difficulties.

Methods: Twenty-one healthy young men were recruited in a 4-day study utilizing daytime (08:00-18:00) exposure with two light conditions in randomized order: dim (< 50 lx) or bright (~2500 lx). Day 1 was for acclimation, and urine flow was assessed from day 2. The participants urinated ad libitum during day 2 and then at fixed 3-4-h intervals thereafter (days 3-4). Regular urination Qmax at late night (04:00) on day 4 was compared with the nearest voided volume during daytime of day 3 (mDay).

Results: Morning Qmax scores (after bed-11:00) on day 2 were significantly lower than evening (17:00-before pre-sleep) in bright conditions and those of daytime (11:00-17:00), evening (17:00-before pre-sleep), and pre-sleep in dim conditions. Pre-sleep Qmax during the ad libitum period was significantly higher in dim than bright conditions. Late-night Qmax values (04:00) on day 4 were significantly lower than Qmax scores of mDay on day 3 in both light conditions.

Conclusions: Healthy young men had a clear diurnal Qmax difference that decreased during late night and morning. In addition, the pre-sleep Qmax values in dim daylight were significantly higher than in bright daylight. Taken together, we conclude that late-night and morning decreases in Qmax are an instinctive physiological phenomenon in humans, and the diurnal difference of Qmax can be influenced by daylight conditions.

Background: Chronotype has gained recognition as a significant factor in enhancing athletic performance. This study aimed to deepen our understanding of athletes' sleep chronotypes and provide a foundation for developing evidence-based training and competition programs. By comprehensively describing and analyzing the chronotype characteristics of Chinese professional athletes, considering individual and sports factors, sleep quality and habits, and mental energy, this research aimed to contribute valuable insights to the field.

Methods: A sample of 1069 professional athletes from sports teams in Shanghai completed the Athlete Sleep Screening Questionnaire and the Athlete Mental Energy Scale to assess chronotype, sleep quality, sleep-influencing habits, and mental energy.

Results: Among athletes, sleep typology fell within the intermediate range, slightly leaning toward morningness. Male athletes and those who engaged in static sports displayed a greater propensity for morningness. Age correlated with a preference for eveningness. High-level athletes exhibited a stronger inclination toward eveningness. Sleep quality issues were associated with an inclination toward eveningness. Daily caffeine intake and the habit of using electronic devices before bedtime are also linked to eveningness. Chronotype demonstrated the ability to predict various dimensions of athletes' mental energy. It was the strongest predictor of vigor, but the loadings were smaller than those of sleep quality.

Conclusion: Chinese athletes' chronotypes primarily exhibit distinct characteristics related to individual factors such as gender, sports discipline, and ranking, as well as habits like caffeine consumption and electronic device use. Moreover, these sleep patterns demonstrate predictive capabilities across all dimensions of athletes' mental energy. This study sheds light on Chinese athletes' unique sleep chronotype attributes, enriching our understanding of sleep patterns among professional athletes under various systems. These insights offer an initial basis for enhancing the effectiveness of athlete scheduling and training management.

Background: Myopia is a common eye disorder that results from gene-environment interactions. The prevalence of myopia varies across populations, and exposure to bright sunlight may prevent its development. We hypothesize that local adaptation to light environments during human migration played a role in shaping the genetic basis of myopia, and we aim to investigate how the environment influences the genetic basis of myopia.

Method: We utilized the whole-genome variant data of the 1000 Genomes Project for analysis. We searched myopia-associated loci that were under selection in Europeans using population branch statistics and the number of segregating sites by length statistics. The outliers of these statistics were enriched in the Kyoto Encyclopedia of Genes and Genomes pathways and the gene ontology biological process terms in searching for pathways that were under selection. We applied Bayesian inference to estimate the correlation between environmental factors and allele frequencies of the selected loci and performed causal inference of myopia using two-sample Mendelian randomization analysis.

Results: We detected signatures of adaptation in vision and light perception pathways, supporting our hypothesis of sunlight adaptation. We discovered a strong correlation between latitude and allele frequencies in genes that are under significant selection, and we found pleiotropic effects of pigmentation or circadian rhythm genes on myopia, indicating that sunlight exposure influences the genetic diversity of myopia.

Conclusions: Myopia genes involved in light perception showed signs of selection. Local adaptation during human migration shaped the genetic basis of myopia and may have influenced its global prevalence distribution.

Background: Surface electromyography (sEMG) is primarily used to analyze individual and neighboring muscle activity. However, using a broader approach can enable simultaneous measurement of multiple muscles, which is essential for understanding muscular coordination. Using the "bull's-eye electrode," which allows bipolar derivation without directional dependence, enables wide-area multipoint sEMG measurements. This study aims to establish a multipoint measurement system and demonstrate its effectiveness and evaluates forearm fatigue and created topographic maps during a grasping task.

Methods: Nine healthy adults with no recent arm injuries or illnesses participated in this study. They performed grasping tasks using their dominant hand, while bull's-eye electrodes recorded their muscle activity. To validate the effectiveness of the system, we calculated the root mean squares of muscle activity and entropy, an indicator of muscle activity distribution, and compared them over time.

Results: The entropy analysis demonstrated a significant time-course effect with increased entropy over time, suggesting increased forearm muscle uniformity, which is possibly indicative of fatigue. Topographic maps visually displayed muscle activity, revealing notable intersubject variations.

Discussion: Bull's-eye electrodes facilitated the capture of nine homogeneous muscle activity points, enabling the creation of topographic images. The entropy increased progressively, suggesting an adaptive muscle coordination response to fatigue. Despite some limitations, such as inadequate measurement of the forearm muscles' belly, the system is an unconventional measurement method.

Conclusion: This study established a robust system for wide-area multipoint sEMG measurements using a bull's-eye electrode setup. This system effectively evaluates muscle fatigue and provides a comprehensive topographic view of muscle activity. These results mark a significant step towards developing a future multichannel sEMG system with enhanced measurement points and improved wearability.

Trial registration: This study was approved by the Ethics Committee of Chiba University Graduate School of Engineering (acceptance number: R4-12, Acceptance date: November 04, 2022).

Background: Heat application before peripheral intravenous catheterization is recommended for venous dilation. Hot pack application enlarges the venous diameter in healthy adults; however, hot towels (moist and dry heat) are used often in some medical cases. However, it is unclear whether hot towel application promotes venous dilation better than hot pack application. This study compared the venous dilation effect of using a hot towel (moist and dry heat) to a hot pack before applying the tourniquet at an access site for peripheral intravenous catheterization.

Methods: Eighty-eight healthy females aged 18-29 years were recruited for this quasi-experimental study. They underwent three types of heat applications (hot pack, moist hot towel, and dry hot towel [moist hot towel wrapped in a dry plastic bag], all of which were warmed to 40 ± 2 °C and performed for 7 min) to their forearm and tourniquet application for 30 s after each heating. Venous diameter and depth were measured using ultrasonography, and venous palpability and visibility (venous assessment score) was observed as venous dilatation effects. In addition, the skin temperature, stratum corneum hydration, and subjective evaluation of the warmth were measured.

Results: There were no significant differences in venous diameter and assessment scores after intervention between the dry hot towel and the hot pack groups, and the effect size was negligible (Cohen's d < 0.20). However, these measurements were significantly lower for the moist hot towel than for the other two heat applications (P < .001). Although there was no significant difference in skin temperature and warmth rating score between the dry hot towel and the hot pack, these were significantly lower for the moist hot towel than for the other two heat applications (P < .001). The amount of change in stratum corneum hydration of the dry hot towel was not significantly different from that of the hot pack; however, that of the moist hot towel was significantly larger than that of the other two heat applications (P < . 001.) CONCLUSIONS: A method in which a towel warmed in hot water is wrapped in a dry barrier may be an alternative to a hot pack.

Trial registration: This study was registered with University Hospital Medical Information Network in Japan (Registration No.: UMIN000048308. Registered on July 7, 2022).