Journal of Physiological Anthropology最新文献

Introduction: Exposure to short-wavelength light (i.e., blue light) has been shown to enhance cognitive function in humans. While most prior studies have focused on visuospatial working memory, the effects of blue light on auditory working memory, particularly tasks involving the phonological loop, remain underexplored. This study investigated both the during- and post-exposure effects of blue light on auditory memory performance.

Methods: Fifteen healthy university students (13 males, 2 females; 21.47 ± 1.06 years old) participated in a randomized crossover design. Each participant was exposed to three lighting conditions for approximately 20-min: blue (λ_max = 476 nm, illuminance = 21.84 lx, 13.8 log photons/s-1.cm-2, melanopic EDI = 169.68 lx), amber (λ_max = 580 nm, illuminance = 61.65 lx, 13.5 log photons/s-1.cm-2, melanopic EDI = 2.87 lx) and dim light (baseline; illuminance < 5.00 lx). Each session was separated by a one-week washout period. To mitigate order effects, the sequence of light conditions was randomized across participants. The modified version of the Sternberg working memory task was performed during light exposure and after a 10-min break (i.e., During- vs Post-exposure phase). The accuracy, reaction time, subject anxiety and subject sleepiness were measured.

Results: In the post-exposure phase, blue light significantly improved accuracy compared to amber (p < 0.01, d = 0.66) and dim light (p < 0.01, d = 0.67). No significant differences were observed during exposure or in reaction time across three light conditions. Anxiety levels were significantly higher during blue light exposure (vs. amber: p = 0.013, d = 0.96; vs. dim: p = 0.027, d = 0.83), while sleepiness remained unchanged.

Conclusions: Blue light exposure may enhance auditory working memory accuracy with a delayed effect, independent of vigilance or processing speed. While these findings are promising, the observed effects are preliminary and require validation in larger and more diverse populations.

Background: Papuan people inhabiting the island of New Guinea are the most ancient population living outside Africa, having resided in the region for at least 50,000 years. The arrival of Austronesian speakers and other group from mainland Asia around 3000 years or so created a peculiar genetic mixture, particularly in lowland/coastal areas. We investigated the anthropometric and blood chemical differences alongside the population structure of the ABCG2 rs2231142 genetic variant of West Papuans from lowland/coastal and highland areas to understand metabolic risk differences between these two populations.

Results: We studied West Papuan students from lowland/coastal areas (n = 78, 45 males, 33 females) and from highland areas (n = 65, 40 males, 25 females). We found the following: (1) The lowland/coastal Papuans were taller, with lower BMI, central obesity, and triceps. Contrarily, highland Papuans have a more gynoid body shape, with higher WC, HC, WHR, and WHtR. The skinfolds were significantly thicker in women from the highlands. (2) There was actually a negative correlation between BMI and central adiposity with UA and FBG to those from the highlands. The lowland/coastal Papuans indicated an Asian-type metabolic traits, with higher fasting glucose levels at lower BMI and lower central adiposity. (3) UA concentration and DBP were strongly correlated with obesity of the Papuans from lowlands/coasts and not in the Papuans from highlands. (4) There was a striking difference in the ABCG2 rs2231142 > T allele frequency in those from the lowlands/coasts (22%) compared to those from the highlands of West Papua (7%). The T variant in the latter is all heterozygous.

Conclusions: The higher adiposity and thicker skinfolds observed in highland Papuans are thought to be adaptive responses to the high-altitude environment, enabling greater adipose tissue expandability and energy storage capacity while maintaining metabolic homeostasis. In contrast, the lowland/coastal Papuans exhibit an Asian metabolic phenotype, which is more prone to metabolic derangements at lower adiposity. Our findings on the population distribution of the ABCG2 rs2231142 > T variant support the idea that its presence in the Papuan highlands is through demic diffusion of the variant from ISEA, indicating that the two populations are separate entities displaying differences in metabolic risks.

Background: Respiratory modulation is generally observed in the inferior vena cava (IVC). If similar respiratory modulation exists in peripheral superficial veins, it would be possible to dilate the vein diameter by respiratory control. This may improve the success rate of venipuncture in clinical practices. Hence, the present study aimed to investigate the respiratory modulation in peripheral superficial veins.

Methods: This study included 21 healthy female volunteers (mean age 21.8 ± 0.9 years). Participants performed spontaneous breathing (SB) and paced breathing (PB). B-mode ultrasound imaging was used to continuously monitor the cutaneous veins of the left elbow fossa for 50 s.

Results: Vein diameter demonstrated a clear modulation consistent with paced breathing, and the amplitude of vein diameter modulation was greater at 10 s-PB than at 3 s-PB. Additionally, PB affected the baseline of modulation (mean vein diameter). The baseline exhibited the largest diameter in SB, followed by 3 s-PB and 10 s-PB. The baseline for SB and 10 s-PB demonstrated a statistically significant difference (p = 0.03). Respiratory modulation was confirmed in peripheral superficial veins; however, tonic change in baseline diameter was dominant over phasic modulation. Even when vein diameter was most dilated at 10 s-PB, the diameter at that time was smaller than the mean diameter at SB.

Conclusions: This study demonstrated that the peripheral superficial vein diameter exhibited respiratory modulation, similar to the IVC. Although respiratory modulation of the IVC has been well documented in previous studies, the present findings provide novel evidence of this phenomenon in the peripheral superficial veins. Additionally, this study identified tonic changes in the mean vein diameter, which were more dominant than phasic modulations. Furthermore, the mean vein diameter during SB was greater than the maximum diameter observed during 10 s-PB. These findings suggested that PB for 50 s during venipuncture did not enhance venous access.

Background: Dietary fiber (DF) is beneficial for preventing constipation, and the metabolites produced by gut microbiota fermentation are suggested to positively influence on depression and sleep. Additionally, constipation has been reported to affect mental health and health-related quality of life (HRQoL). This study aimed to increase DF intake and examined its effects on daily DF and β-G consumption using two types of waxy barley (WB), rich in DF with varying β-glucan (β-G) content. Additionally, this study examined the effects of WB consumption on defecation, sleep, mental health, and HRQoL.

Methods: A randomized double-blind parallel-group comparison study was conducted on 68 young Japanese women, using Kirarimochi (Group K) as common WB cultivar and Fukumi Fiber (Group F) as high-β-G WB cultivar. Participants consumed WB rice for 4 weeks, targeting 3 g/day of β-G (48 g/day of WB). We estimated the intake of WB and DF including β-G from the daily records. Defecation was evaluated through daily records and Rome IV criteria-based surveys. Sleep, mental health, and HRQoL were evaluated using PSQI-J, J-PHQ-9, and SF-36, respectively.

Results: Both groups consumed about 40 g/day of WB. DF and β-G intakes from barley were 6.3 g/2.5 g in Group K and 10.7 g/4.3 g in Group F. Regarding defecation, both groups showed increases defecation days, defecation frequency and stool amount, with no differences between groups. Regarding sleep, Group F showed a decrease (improvement) in the PSQI global score, with improvements noted between groups. Regarding mental health, both groups showed decreases (improvements) in the PHQ-9 score, with Group F showing improvement between groups. Regarding HRQoL, summary scores showed improvements: physical health in Group K and mental health in Group F.

Conclusion: To increase β-G intake, high-β-G WB cultivars are effective; however, WB cultivars overall can potentially serve as excellent sources of DF. Effects on defecation may be expected not only from high-β-G WB but also from common WB with β-G intake below the target of 3 g/day. Although high β-G WB may have more beneficial for sleep and mental health, additional studies are required.

Brown adipose tissue (BAT) is a site of non-shivering thermogenesis (NST) in mammals. Since the rediscovery of BAT in adult humans, there has been a remarkable advance in human BAT researches, revealing the significant roles of this thermogenic tissue in cold-induced NST and cold adaptation. Cold stress influences BAT in various time spans: acute cold exposure promptly activates BAT to induce NST, which contributes to immediate maintenance of body temperature. Prolonged cold exposure recruits BAT, resulting in increased capacity of NST and improved cold tolerance. Such BAT adaptation not only occurs in the exposed individual but also is passed on to the next generation, probably via the paternal lineage. As such, BAT plays a role in acute, chronic, and transgenerational adaptation to cold environment in humans.

Background: Acute physical exercise, even at a very-light-intensity, potentiates prefrontal cortex activation and improves executive function. The underlying circuit mechanisms in the brain remain poorly understood, though we speculate a potential involvement of arousal-related neuromodulatory systems. Recently, our rodent study demonstrated that exercise, even at light-intensity, activates the midbrain dopaminergic neurons. Resting-state spontaneous eye blink rate is linked to brain-arousal neural circuits, and potentially to those modulated by dopaminergic system. We hypothesized that neural substrates linked to resting-state eye blink rate contribute to the cognitive impact of acute very-light-intensity exercise.

Method: We analyzed data from a previous study with a renewed focus on resting-state eye blink rate. Twenty-four healthy young adults completed both 10 min of cycling (very-light-intensity exercise: 30% peak oxygen uptake) and rest conditions. Resting-state eye blink rate and Stroop task performance were measured before and after both exercise and resting control.

Results: Results showed no significant differences in eye blink rate changes between conditions. However, correlation analyses revealed that exercise-induced changes in resting-state eye blink rate were significantly associated with individual variations in Stroop task performance enhancement.

Conclusion: Very-light-intensity exercise does not elicit a consistent increase in eye blink rate after exercise. This finding does not support the involvement of a blink increase-linked neural substrate in enhancing executive function through very-light-intensity exercise. However, resting-state eye blink rate that is altered by exercise is predictive of executive function enhancement levels; this may serve as a novel contactless biomarker for predicting exercise benefits for brain health and cognition.

Introduction: Low-intensity physical activity plays a key role in weight regulation, and reduced engagement in such activities is associated with rising obesity rates. This study explored the relationship between body fat distribution and exercise efficiency during low-intensity cycling, comparable to everyday life, focusing on adiposity in men and women.

Methods: Thirty participants (50% women and 50% men) underwent basal metabolic rate (BMR) measurements after an overnight fast. Following 500 ml water intake, they cycled at 60 rpm for 5 min at four intensities (20 W, 40 W, 60 W, 80 W), with respiratory parameters (i.e., energy expenditure (EE)) recorded using an indirect calorimeter system. Spearman correlations were used to assess the relationships among BMI, total body and trunk fat percentages, and delta efficiency (DE), which quantifies the energy cost associated with incremental work output during exercise.

Results: A linear increase in EE with increasing power output was observed in both men and women, with men showing a slightly higher EE across all power levels. The linear regression equations for power between 20 and 80 W were highly predictive, with R² values of 0.999 for men and 0.995 for women. Additionally, significant positive correlations were observed between BMI, fat percentage, trunk and limb fat percentages, and delta efficiency (DE) in women, explaining 45.7%, 34.7%, 34.1%, and 29.7% of the variance in DE, respectively. No significant correlations were found between these variables in men.

Conclusion: This study demonstrated that body fat distribution, particularly in women, is significantly associated with exercise efficiency during low-intensity cycling. These findings highlight the need for larger studies that incorporate gender-specific considerations in exercise and targeted interventions.

Background: Bioelectrical impedance analysis (BIA) is widely used as a convenient method of measuring body composition. The validity of the phase angle (PhA), impedance rate (IR), and resistance rate (RR) as indices of muscle quality using BIA has been suggested. This study aimed to investigate the relationship between these muscle quality indices and age, and to clarify their characteristics.

Methods: The appendicular muscle mass (AMM), AMM corrected for body mass index (AMM/BMI), PhA, IR, and RR were determined using BIA in 1376 Japanese individuals (532 males and 844 females) aged 15-95 years. The PhA was determined from a 50-kHz current, and the IR and RR were determined from the impedance and resistance ratios between the 250- and 5-kHz currents.

Results: AMM/BMI showed greater age-related changes than the other indices of muscle mass. Significant differences in PhA, IR, and RR were found for the whole body at age ≥ 50 years and for the lower limbs at age ≥ 30 years, compared to those in their 20 s. For the arms, age-related changes were small, and significant differences in PhA of females were only observed at aged ≥ 85 years, whereas significant differences in IR and RR were observed at aged ≥ 75 years, compared to those in their 20s.

Conclusion: These results suggest that although PhA, IR, and RR in the whole body and lower limbs showed age-related changes, the change in PhA in the upper body was small, especially in females. However, IR and RR in the upper limbs of females reflected age-related changes more than PhA.

This review aims to update our understanding of human cold adaptation. First, an overview of the thermoregulatory response to cold is provided, with some recent updates in human brown adipose tissue (BAT). Variation in BAT activity and multiorgan contributions to cold-induced thermogenesis were introduced. We found that individuals with less BAT activity rely more on shivering to compensate for less non-shivering thermogenesis (NST). The mechanisms of cold-induced vasoconstriction are summarized, including the role of arteriovenous anastomoses, adrenergic neural function, and inhibition of the nitric oxide vasodilator pathway. In addition, cold-induced vasodilation (CIVD) during cold immersion of the distal extremities is summarized with some recent updates in physiological mechanism. Furthermore, the cold shock response at the onset of cold immersion is introduced. Next, categorization of cold acclimatization/acclimation into habituation of shivering and metabolic and insulative adaptation are provided, with some recent updates. Especially, the rediscovery of human BAT has clarified metabolic acclimation, where increased NST replace shivering. Then, a greater CIVD response in populations in cold regions has been reported, whereas recent laboratory studies suggest no increase in CIVD after repeated cold exposure. To prevent cold injuries, individuals should not rely on habituation through repeated cold exposure. In addition, habituation to the cold shock response after repeated cold water immersion could help reduce the number of drownings. Furthermore, cross-adaptation between cold and nonthermal factors in the thermoregulatory response is summarized. Recent studies explored the relationship between exercise training and BAT activity, although this remains unresolved, depending on the exercise intensity and environmental conditions. The effects of exercise with cold exposure on the thermoregulatory response to cold are summarized in studies including divers working in cold water. We investigated the effect of exercise training in cold water, which resulted in increased muscle deoxygenation during submaximal exercise and greater anerobic power. Moreover, the effects of a hypoxic environment on cold adaptation are summarized. Elevated basal metabolism and higher distal skin temperature in highlanders could improve their cold tolerance. Finally, factors affecting cold adaptation are discussed. The type of cold adaptation may depend on the specific thermoregulatory responses repeated during the adaptation process.

Background: Prediction of sports success (sports talent) based on individual genetic characteristics is the main goal of sports genetics/genomics. Most often, markers of predisposition to speed-strength sports, or endurance, are single-nucleotide variants in various parts of DNA. One of the most studied variants is the C/T variant in the ACTN3 gene. The accumulated data on the association of this variant with success in various sports is sufficient to conduct a meta-analysis. The purpose of the present review is to analyze the prognostic utility of the data presented in the literature on molecular genetic markers of genetic predisposition to achieve outstanding sports results using the example of the C > T variant of ACTN3 (rs1815739).

Main body: A total of 42 studies were included in the analysis, with a total number of 41,054 individuals (of which 10,442 were in the athlete group and 30,612 in the control group). For each study included in the analysis, the agreement of genotype frequencies with Hardy-Weinberg equilibrium was tested, as well as the presence of an excess or deficit of heterozygotes. Prediction intervals for the overall effect size (OR-odds ratio) was estimated. Both in the subgroups of athletes and controls, a significant difference F_IS from zero was found, suggesting inbreeding or outbreeding, as well as a very wide 95% CI for F_IS. A meta-analysis was conducted for dominant, codominant, and recessive inheritance models. The obtained ORs and their 95% CIs were in the range of almost negligible values or have very wide CIs. The evaluation for the recessive model showed 95% PI for the OR lies between 0.74 to 1.92. Statistically, it does not differ from zero, which means that in some 95% of studies comparable to those in the analysis, the true effect size will fall in this interval.

Conclusion: Despite numerous attempts to identify genetic variants associated with success in elite sports, progress in this direction remains insignificant. Thus, no sports or sports roles were found for which the C > T variant of the ACTN3 gene would be a reliable prognostic marker for assessing an individual predisposition to achieve high sports performance. The results of the present meta-analysis support the conclusion that neutral gene polymorphism-from evolutionary or adaptive point of view-is not a trait that can be selected or used as a predictive tool in sports.