Ecological risk of metals in Andean water resources: A framework for early environmental assessment of mining projects in Peru.

Metallic contaminants in Andean water resources influenced by mining activities poses risks to aquatic ecosystems and a challenge to regulatory agencies responsible for environmental compliance. In this study, the Ecological Risk Assessment (ERA) framework was adapted to assess dissolved heavy metal concentrations at 283 surface water monitoring stations near to six mining projects during the dry and wet seasons. Reports from OEFA-Peru on Early Environmental Assessment (EEA) were used to apply various criteria and non-parametric statistical tests. They included ecological, ecotoxicological, chemical, and regulatory factors. The main goal of this research was to identify, analyze, characterize, and compare the risks present at different trophic levels. These levels were categorized as T1 (Microalgae), T2 (Zooplankton and Benthic invertebrates), and T3 (Fish). Individual risk (IR) was estimated using the quotient model, while total risk (TR) was assessed using the additive probability rule. Rainbow trout (Oncorhynchus mykiss), representing trophic level T3, showed the highest sensitivity to Fe and Cu. Statistical tests ranked the IR as Fe > Cu > Zn > Mn > Pb (p < 0.01). The TR was more prevalent during the wet season compared to the dry season (p < 0.01). Notably, around 50 % of the monitoring stations (n = 142) were classified as high risk, and 9 % (n = 13) showed extremely high-risk values for Cu and Fe. The adapted ERA framework demonstrated great effectiveness in identifying critical points of metal contamination in high Andean aquatic ecosystems under mining influence. However, specialized studies are suggested that allow the sources of pollution to be associated with specific regulatory actions.

Discipline and punishment in panoptical public goods games.

In Public Goods Games (PGG), the temptation to free-ride on others' contributions poses a significant threat to the sustainability of cooperative societies. Therefore, societies strive to mitigate this through incentive systems, employing rewards and punishments to foster cooperative behavior. Thus, peer punishment, in which cooperators sanction defectors, as well as pool punishment, where a centralized punishment institution executes the punishment, is deeply analyzed in previous works. Although the literature indicates that these methods may enhance cooperation on social dilemmas under particular contexts, there are still open questions, for instance, the structural connection between graduated punishment and the monitoring of public goods games. Our investigation proposes a compulsory PGG framework under Panoptical surveillance. Inspired by Foucault's theories on disciplinary mechanisms and biopower, we present a novel mathematical model that scrutinizes the balance between the severity and scope of punishment to catalyze cooperative behavior. By integrating perspectives from evolutionary game theory and Foucault's theories of power and discipline, this research uncovers the theoretical foundations of mathematical frameworks involved in punishment and discipline structures. We show that well-calibrated punishment and discipline schemes, leveraging the panoptical effect for universal oversight, can effectively mitigate the free-rider dilemma, fostering enhanced cooperation. This interdisciplinary approach not only elucidates the dynamics of cooperation in societal constructs but also underscores the importance of integrating diverse methodologies to address the complexities of fostering cooperative evolution.

Mpox: Fifty-Nine Consecutive Cases from a Mexican Public Hospital; Just the Tip of the STIs Iceberg.

Monkeypox (Mpox) is a zoonotic viral infection endemic to Africa, which has caused a global outbreak since April 2022. The global Mpox outbreak is related to Clade IIb. The disease has primarily affected men who have sex with men. Skin lesions are concentrated in the genital area, with lymphadenopathy as well as concurrent sexually transmitted infections (STIs). This is an observational study of adult patients with a recent development of skin lesions and systemic symptoms, which could not be explained by other diseases present. Fifty-nine PCR-positive patients with prominent skin lesions in the genital area (77.9%), inguinal lymphadenopathy (49.1%), and fever (83.0%) were included. Twenty-five (42.3%) were known to be living with human immunodeficiency virus (HIV), and 14 of the HIV-naïve subjects (51.9%) were found to be positive during workup, totaling 39 (66.1%) patients with HIV. Eighteen patients (30.5%) had concurrent syphilis infections. It is worrisome that Mpox is present in large metropolitan areas of Mexico, but the underlying growth of cases of HIV infection and other STIs has not been well studied and should be evaluated in all at-risk adults and their contacts.

Latin American Initiative for Lifestyle Intervention to Prevent Cognitive Decline (LatAm-FINGERS): Study design and harmonization.

INTRODUCTION: Latin American Initiative for Lifestyle Intervention to Prevent Cognitive Decline (LatAm-FINGERS) is the first non-pharmacological multicenter randomized clinical trial (RCT) to prevent cognitive impairment in Latin America (LA). Our aim is to present the study design and discuss the strategies used for multicultural harmonization. METHODS: This 1-year RCT (working on a 1-year extension) investigates the feasibility of a multi-domain lifestyle intervention in LA and the efficacy of the intervention, primarily on cognitive function. An external harmonization process was carried out to follow the FINGER model, and an internal harmonization was performed to ensure this study was feasible and comparable across the 12 participating LA countries. RESULTS: Currently, 1549 participants have been screened, and 815 randomized. Participants are ethnically diverse (56% are Nestizo) and have high cardiovascular risk (39% have metabolic syndrome). DISCUSSION: LatAm-FINGERS overcame a significant challenge to combine the region's diversity into a multi-domain risk reduction intervention feasible across LA while preserving the original FINGER design.

SIR-SI model with a Gaussian transmission rate: Understanding the dynamics of dengue outbreaks in Lima, Peru.

INTRODUCTION: Dengue is transmitted by the Aedes aegypti mosquito as a vector, and a recent outbreak was reported in several districts of Lima, Peru. We conducted a modeling study to explain the transmission dynamics of dengue in three of these districts according to the demographics and climatology. METHODOLOGY: We used the weekly distribution of dengue cases in the Comas, Lurigancho, and Puente Piedra districts, as well as the temperature data to investigate the transmission dynamics. We used maximum likelihood minimization and the human susceptible-infected-recovered and vector susceptible-infected (SIR-SI) model with a Gaussian function for the infectious rate to consider external non-modeled variables. RESULTS/PRINCIPAL FINDINGS: We found that the adjusted SIR-SI model with the Gaussian transmission rate (for modelling the exogenous variables) captured the behavior of the dengue outbreak in the selected districts. The model explained that the transmission behavior had a strong dependence on the weather, cultural, and demographic variables while other variables determined the start of the outbreak. CONCLUSION/SIGNIFICANCE: The experimental results showed good agreement with the data and model results when a Bayesian-Gaussian transmission rate was employed. The effect of weather was also observed, and a strong qualitative relationship was obtained between the transmission rate and computed effective reproduction number Rt.

Caracterización clínica-epidemiológica de quiste de colédoco en la población infantil atendida en el Hospital Materno Infantil

Objetivo: Realizar caracterización clínica-epidemiológica de quiste de colédoco en la población infantil atendida en el Hospital Materno Infantil. Material y Método: Estudio transversal, retrospectivo, descriptivo. La población del estudio consistió en los expedientes con diagnóstico de quiste de colédoco (QC) en el servicio de cirugía pediátrica. Criterios de inclusión: desde el nacimiento hasta los 18 años, operados en este hospital, diagnóstico clínico e imagenológico. Análisis estadístico: base de datos Epi Info.12.0, usando medidas de frecuencia, como la media y varianza. Resultados: Un total de 12 pacientes, la relación entre mujer hombre fue de 3:1, con predominio en mujeres. El grupo etario con mayor frecuencia fue el preescolar con 41,7%. El síntoma más frecuente fue el dolor abdominal con 83,3%; el tipo de QC más frecuente fue el tipo I con 75%, todos fueron resecados y la reconstitución de tránsito más utilizada fue la hepaticoyeyuno anastomosis en Y de Roux (HYYR) con 83,3%. Discusión: El grupo etario, el sexo y el tipo de QC en este estudio, coincide con la literatura citada. El ultrasonido puede ser suficiente para el diagnóstico de QC, la colangiopancreatografia por resonancia magnética permite identificar el subtipo de quiste y planificar la intervención quirúrgica. Conclusión: en nuestro hospital hay poca experiencia en la realización de hepaticoduodeno anastomosis (HD) y ninguna experiencia en la realización de HD y HYYR laparoscópicas, por lo cual, se plantea la necesidad de mejorar las opciones terapéuticas según estándares internaciones. Además, tomando este estudio como base, se deben realizar investigaciones posteriores con mayor complejidad metodológica.

Objective: To perform a clinical-epidemiological characterization of choledochal cyst in the pediatric population attended at the Hospital Materno Infantil. Material and Methods: Cross-sectional, retrospective, descriptive study. The study population consisted of records with a diagnosis of choledochal cyst (CC) in the pediatric surgery service. Inclusion criteria: from birth to 18 years of age, operated in this hospital, clinical and imaging diagnosis. Statistical analysis: Epi Info.12.0 database, using frequency measures, such as mean and variance. Results: A total of 12 patients, female to male ratio was 3:1, with female predominance. The age group with the highest frequency was preschool with 41.7%. The most frequent symptom was abdominal pain with 83.3%, the most frequent type of CC was type I with 75%, all of them were resected and the most frequent reconstruction was Roux-en-Y hepaticojejunostomy (HJ) with 83.3%. Discussion: The age group, sex and type of CC in this study coincides with the literature cited. Ultrasound may be sufficient for the diagnosis of CC, magnetic resonance cholangiopancreatography allows identification of the subtype of cyst and planning of surgical intervention. Conclusion: In our hospital there is little experience in performing hepaticoduodenostomy (HD) and no experience in performing laparoscopic HD and HJ, therefore, there is a need to improve the therapeutic options according to international standards. Furthermore, taking this study as a basis, further research with greater methodological complexity should be carried out.

Active warm-up and time-of-day effects on repeated-sprint performance and post-exercise recovery.

PURPOSE: This study investigated the effects of both an active warm-up and the time-of-day variation on repeated-sprint performance. A second objective was to compare the post-exercise recovery between the experimental conditions. METHODS: Eleven male participants performed ten maximal cycling sprints (6 s each, with a 30-s interval between them) in the morning and late afternoon, either after a warm-up or control condition. The warm-up consisted of cycling for 10 min at 50% of the peak aerobic power. RESULTS: Rest measurements of rectal, muscle, and skin temperatures were higher in the afternoon compared to the morning (p < 0.05), with no significant differences in heart rate (p = 0.079) and blood lactate concentration (p = 0.300). Warm-up increased muscle temperature, heart rate, and lactate, and reduced skin temperature (all p < 0.001), though no significant differences were observed for rectal temperature (p = 0.410). The number of revolutions (p = 0.034, ηp2 = 0.375), peak (p = 0.034, ηp2 = 0.375), and mean (p = 0.037, ηp2 = 0.365) power of the first sprint (not the average of ten sprints) were higher in the afternoon compared to the morning, regardless of warm-up. However, beneficial performance effects of warming up were evident for the first (p < 0.001) and the average of ten sprints (p < 0.05), regardless of time of day. More remarkable changes during the 60-min post-exercise were observed for rectal temperature (p = 0.005) and heart rate (p = 0.010) in the afternoon than in the morning. CONCLUSION: Warming-up and time-of-day effects in enhancing muscular power are independent. Although warm-up ensured further beneficial effects on performance than the time-of-day variation, a faster post-exercise recovery was observed in the late afternoon.

A critical assessment of the detailed Aedes aegypti simulation model Skeeter Buster 2 using field experiments of indoor insecticidal control in Iquitos, Peru.

The importance of mosquitoes in human pathogen transmission has motivated major research efforts into mosquito biology in pursuit of more effective vector control measures. Aedes aegypti is a particular concern in tropical urban areas, where it is the primary vector of numerous flaviviruses, including the yellow fever, Zika, and dengue viruses. With an anthropophilic habit, Ae. aegypti prefers houses, human blood meals, and ovipositioning in water-filled containers. We hypothesized that this relatively simple ecological niche should allow us to predict the impacts of insecticidal control measures on mosquito populations. To do this, we use Skeeter Buster 2 (SB2), a stochastic, spatially explicit, mechanistic model of Ae. aegypti population biology. SB2 builds on Skeeter Buster, which reproduced equilibrium dynamics of Ae. aegypti in Iquitos, Peru. Our goal was to validate SB2 by predicting the response of mosquito populations to perturbations by indoor insecticidal spraying and widespread destructive insect surveys. To evaluate SB2, we conducted two field experiments in Iquitos, Peru: a smaller pilot study in 2013 (S-2013) followed by a larger experiment in 2014 (L-2014). Here, we compare model predictions with (previously reported) empirical results from these experiments. In both simulated and empirical populations, repeated spraying yielded substantial yet temporary reductions in adult densities. The proportional effects of spraying were broadly comparable between simulated and empirical results, but we found noteworthy differences. In particular, SB2 consistently over-estimated the proportion of nulliparous females and the proportion of containers holding immature mosquitoes. We also observed less temporal variation in simulated surveys of adult abundance relative to corresponding empirical observations. Our results indicate the presence of ecological heterogeneities or sampling processes not effectively represented by SB2. Although additional empirical research could further improve the accuracy and precision of SB2, our results underscore the importance of non-linear dynamics in the response of Ae. aegypti populations to perturbations, and suggest general limits to the fine-grained predictability of its population dynamics over space and time.

A comparison of rural-urban differences in out-of-pocket expenses among older Mexicans with diabetes.

Objective: To compare total out-of-pocket expenses for physician visits and medications among older adults living with diabetes in Mexico from urban, semi-urban, and rural areas. Methods: The sample included 2,398 Mexicans aged 65 years and older with self-reported diabetes from the 2018 Mexican Health and Aging Study. Out-of-pocket expenses for physician visits and medications were regressed on locality, controlling for several factors. Results: The profile of those with higher out-of-pocket medication expenditures included rural localities, higher education, unmarried, depressive symptoms, participation in Seguro Popular, and lacking insurance. In the multivariate analysis, rural older adults with diabetes paid a higher amount in medication expenditures compared with other localities. Conclusion: Differences in locality are closely tied to the effective implementation of Seguro Popular. Although this program has improved access to care, participants have higher out-of-pocket expenditures for medications than those on employer-based plans across all localities. Among all groups, the uninsured bare the highest burden of expenditures, highlighting a continued need to address health inequities for the most underserved populations.

Don't take the context out of the picture: Contextually shaped parents' and children's obesogenic behaviors in a marginalized area of Mexico City.

Santa Fe Gully zone is a marginalized area of Mexico City where nearly 39% of children live with either overweight or obesity. Despite the extensive research on obesogenic behaviors, studies frequently overlook the contexts where such behaviors occur. This qualitative study described individual and familial obesogenic behaviors among children with obesity from Santa Fe Gully, and explained how these behaviors might be contextually shaped. We used a grounded theory approach to investigate the process of development/maintenance of obesity in our sample. Fifteen participants (seven 10-year-olds with overweight or obesity and their parents) participated in nine art-based focus groups, and parents completed individual semi-structured interviews. Data were analyzed using a structured thematic content analysis. Results showed children's weight status was part of their identity, providing children with a familial 'fitting' sense while increasing psychosocial difficulties, leading to emotional overeating as a coping strategy. Parents' use of controlling and low-structured parenting practices reinforced children's emotional overeating and failed to regulate children's dietary and physical activity behaviors. Some low-structured parenting practices were guilt-motivated or fostered by socioeconomic and cultural factors (e.g., limited food access, unhealthy food exposure, community unsafety). Future interventions in Santa Fe Gully aimed at modifying obesogenic behaviors should incorporate systemic and ecological approaches to help participants navigate through contextual obstacles, as their behaviors should be analized considering the context where they occur.

Social capital in Mexico moderates the relationship of uncertainty and cooperation during the SARS-COV-2 pandemic.

This study proposes that, given the coronavirus disease 2019 pandemic, its sanitary restrictions, and the associated economic effects, citizens perceive higher uncertainty and tend to reduce their willingness to cooperate with others. Community social capital refers to a set of norms of reciprocity, trust, and civic engagement networks that promote trust, reciprocal help, and cooperation for mutual benefits. It is also suggested that it can help alleviate negative effects of the pandemic in communities, by reducing uncertainty and its harmful effects on cooperation. These hypotheses were tested in a sample of 565 inhabitants of Mexico, who answered an online survey with measurements of social capital, uncertainty, and willingness to cooperate in the face of the pandemic. The relationships between variables were analyzed in two structural equation models, which show adequate goodness of fit, where higher levels of uncertainty generated by the pandemic were associated with a greater disposition to noncooperation with others, while social capital moderated this relation decreasing negative effects of uncertainty on noncooperation. The value of social capital is discussed as a resource worth preserving and promoting in communities to strengthen them, so that they are better able to face health or economic contingencies.

Social isolation after acquired brain injury: Exploring the relationship between network size, functional support, loneliness and mental health.

Social isolation can be a consequence of acquired brain injury (ABI). Few studies have examined the relationship between social isolation and mental health after ABI. In this cross-sectional and case-control study, we compared 51 ABI survivors and 51 matched healthy controls on measures of social isolation (network size, social support and loneliness) mental health and mental health problems. We explored the relationship between structural, functional and subjective components of social isolation and examined whether they were associated with mental health outcomes. No group differences were found on size of the network and perceived social support. The ABI group exhibited marginally higher levels of loneliness. The ABI group presented higher levels of depression, lower levels of quality of life and emotional wellbeing. In both groups, perception of social support was inversely related to subjective experience of loneliness. The relationship between network size and loneliness was only significant in the ABI group. Only loneliness significantly predicted quality of life, emotional wellbeing, depression and anxiety in people with brain injury. The relationship between social isolation variables in ABI is discussed, as well as the theoretical and clinical implications of focusing on loneliness to improve mental health after brain injury.

Quantification and health risk assessment of heavy metals in residual floor dust at an indoor firing range: A case study in Trinidad, WI.

Residual floor dust at an indoor firing range was investigated for the presence of selected heavy metals, and the associated health risks (non-carcinogenic and carcinogenic) were explored. Average heavy metal concentrations decreased in the following order: Pb >> Cu >> Zn > Mn > Cr > Ni > Cd. For the examined floor dust, moderate to significant degrees of enrichment were observed for Ni, Cd, Cr and Zn while extremely high degrees of enrichment were reported for Cu and Pb. Lead was the only heavy metal that exceeded the Hazard Index value of 1 and the potential carcinogenic risks for Cd and Ni were considered acceptable. A potential carcinogenic risk existed for Cr, as denoted by a total lifetime cancer risk value greater than 10-4.

Determining the Arterial Occlusion Pressure for Blood Flow Restriction: Pulse Oximeter as a New Method Compared With a Handheld Doppler.

ABSTRACT: Lima-Soares, F, Pessoa, KA, Torres Cabido, CE, Lauver, J, Cholewa, J, Rossi, FE, and Zanchi, NE. Determining the arterial occlusion pressure for blood flow restriction: Pulse oximeter as a new method compared with a handheld Doppler. J Strength Cond Res 36(4): 1120-1124, 2022-In laboratorial and clinical settings, the use of Doppler ultrasound equipment has been considered the gold standard method to determine arterial occlusion pressure (AOP). However, the use of Doppler equipment is inherently limited to the technical expertise needed to perform AOP measurements. To overcome the technical difficulties of the use of Doppler equipment use in the determination of AOP, a simpler and less subjective methodology would be helpful for blood flow restriction (BFR) practitioners. In this regard, portable pulse oximetry has been largely used in clinical practice for measuring systolic pressures, as well as loss or recovery of pulse, with results similar to those observed with the use of Doppler equipment. For such purposes, the AOP from young male and female subjects was evaluated after different body positions (standing, seated, and supine positions). Loss of capillary blood flow or AOP was readily determined by simple visual inspection for the pulse oximeter and loss of sound for the Doppler equipment. The results presented herein strongly suggest the use of the portable pulse oximetry equipment as reliable, when compared with the handheld Doppler (seated k = 0.962, standing k = 0.845, and supine k = 0.963 and seated rs = 0.980, standing rs = 0.958, and supine rs = 0.955). Because AOP measurement by pulse oximetry is relatively easier to perform and financially more accessible than handheld Doppler equipment, BFR practitioners may benefit from this new methodology to measure AOP, thus determining individualized restriction pressures.

A Novel Theoretical Probabilistic Model for Opportunistic Routing with Applications in Energy Consumption for WSNs.

This paper proposes a new theoretical stochastic model based on an abstraction of the opportunistic model for opportunistic networks. The model is capable of systematically computing the network parameters, such as the number of possible routes, the probability of successful transmission, the expected number of broadcast transmissions, and the expected number of receptions. The usual theoretical stochastic model explored in the methodologies available in the literature is based on Markov chains, and the main novelty of this paper is the employment of a percolation stochastic model, whose main benefit is to obtain the network parameters directly. Additionally, the proposed approach is capable to deal with values of probability specified by bounded intervals or by a density function. The model is validated via Monte Carlo simulations, and a computational toolbox (R-packet) is provided to make the reproduction of the results presented in the paper easier. The technique is illustrated through a numerical example where the proposed model is applied to compute the energy consumption when transmitting a packet via an opportunistic network.

Water footprint in gold extraction: A case-study in Suárez, Cauca, Colombia.

This research deepens the analysis of the mineral water footprint, especially that of gold, in regions that are understudied and where mining has been an intensified extractive activity since the colonial era, as is the case in the northern part of department of Cauca in Colombia. Thus, the purpose was to estimate the water footprint indicators in gold mining in Suárez (Cauca, Colombia), to quantify the impacts generated by the non-returned water in the production process and the levels of pollutants in the wastewater, aimed to strength public policies, control strategies and mitigation that generates reductions in the impacts from mining activities on the environment. The blue water footprint was estimated in 79.91 m3 per kg of gold extracted and the gray water footprint was found to be in the range of 272,125.39 to 404,825.11 m3 per kg of gold extracted. The water footprint values obtained were compared with other mines with similar operations. These results generate a baseline for decision making, providing elements for environmental strategic planning, regulations and showing the great environmental pressure that gold activity exerts on water resources and the territories.

Couples extrinsic emotion regulation questionnaire: Psychometric validation in a Chilean population.

The way couples regulate their emotions affects the quality of their relationship. Despite this, no evidence-based scales of validity and reliability can measure the intention to regulate emotions in the romantic dyad. In order to address this gap, we developed the Couples Extrinsic Emotion Regulation (CEER) questionnaire. First, we adapted the "Others" subscale from the Emotion Regulation of Others and Self questionnaire (EROS) for any close relationship to measure the intention to regulate emotions in couples; second, the psychometric properties of the CEER questionnaire were studied. For the content validity assessment, 23 experts (47.8% of whom worked in social and health psychology and the psychology of emotions, 17.4% in couples' therapy, and 34.8% in social science methodologies) participated. A total of 528 Chileans completed the online CEER questionnaire, the relationship satisfaction scale (RAS) and dyadic adjustment scale (DAS): 27.8% were male, age M = 38.7, SD = 10.05, and time of the relationships M = 11.27, SD = 9.82. The content-based validity study made it possible to determine which items to include in the final version. Two unrelated first-order factors structure of the original test fit (RMSEA = .052, GFI = .97, AGFI = .95; CFI = .99; NFI = .98; and NNFI = .98). The CEER+ and CEER- factors presented adequate internal consistency (α = .79; ω = .80 and α = .85; ω = .85, respectively). The discrimination index of the factors were excellent (CEER+ = .55 and CEER- = .63). Validity evidence based on the relations to other variables showed a direct positive relation between CEER+, RAS and overall DAS, as well as their factors; and a negative relation between CEER-, RAS overall DAS, as well as their factors. The use of this instrument is recommended for the identification of Chilean couples where at least one of the partners has a less favorable opinion of their relationship, providing relevant data for couple's therapy.

Local economies and household spacing in early chiefdom communities.

Archaeological research has by now revealed a great deal of variation in the way early complex societies, or chiefdoms, developed. This variation is widely recognized, but our understanding of the forces that produced it remains relatively undeveloped. This paper takes aim at such understanding by exploring variation in the local economies of six early chiefdoms; it considers what implications this variation had for trajectories of chiefdom development, as well as the source of that variation. Economic exchange is a primary form of local interaction in all societies. Because of distance-interaction principles, closer household spacing within local communities facilitated more frequent interaction and thus encouraged productive differentiation, economic interdependence, and the development of well-integrated local economies. Well-integrated local economies, in turn, provided ready opportunities for aspiring leaders to accumulate wealth and fund political economies, and pursuit of these opportunities led to societies with leaders whose power had a direct economic base. Wider household spacing, on the other hand, impeded interaction and the development of well-integrated local economies. In such contexts, aspiring leaders were able to turn to ritual and religion as a base of social power. Even when well-integrated local economies offered opportunities for wealth accumulation and a ready source of funding for political economies, these opportunities were not always taken advantage of. That variation in the shapes of early chiefdoms can be traced back to patterns of household spacing highlights the importance of settlement and interaction in explaining not just chiefdom development, but societal change more generally.

Physiological responses during the long-distance race in the warm environment in runners: a pilot-study.

BACKGROUND: This study investigated the effects of warm temperature in the external environment on physiological response in self- pace during the long-distance race in runners and the association between the physiological index of endurance performance (i.e., speeds at ventilatory anaerobic threshold [VVAT], respiratory compensation [VRCP], maximum oxygen uptake [VVO2max], and running economy) and average pace for each 3-km during the 21-km race. METHODS: Five male recreational runners (mean±SE age 36.6±6.1 years; VO2 max: 59.2±7.9) were submitted to a 21-kilometers race in the outdoor environment using a portable metabolic analyzer. RESULTS: Our results showed a reduction in speed to kilometers 12, 15, 18 and 21 than kilometer 3 (P<0.05). The runners showed a decrease in both VO2 (mL/kg/min) and RER from kilometer 15 (P=0.001 and P=0.003, respectively). Regarding cardiovascular response, our data demonstrated a steady HR response from kilometer 6 to 21 (P=0.99). Otherwise, the runners showed a decrease in oxygen pulse from kilometer 9 than both kilometers 3 and 6 (P=0.001). During the race, the runners demonstrated a significant increase in body temperature compared to rest (P=0.001). The results of the correlation analysis between physiological index of endurance performance and average pace for each 3-km during the 21-km race showed significant correlation between VVAT and average pace for: 12-km (r=0.95; P=0.01), 15-km (r=0.89; P=0.05) and 21-km (r=0.86; P=0.04); VRCP and average pace for 3-km (r=0.88; P=0.05). CONCLUSIONS: Our findings demonstrated that the increase in body temperature in a warm environment during the 21-km race is associated with both cardiovascular and metabolic strain in runners. Concerning physiological markers of endurance performance, VVAT appears to be the best predictor of the average pace throughout the 21-km race in a warm environment in recreational runners.