Mercúrio e Amálgama Odontológico: Implicações para a Saúde Coletiva

Environmental pollution and occupational exposures by Mercury have been associated with many health problems since the fetal life. Since amalgam is widely used in dentistry due to its ease use and lower cost, the objective of this work was to elaborate a review regarding Mercury pollution and environmental, occupational and health aspects. A review covering 2010 to 2014 period using Medline, ISI, and LILACS databases were done. Mercury is associated with reduction of physical growth and cognitive development in children as well as psycho-affective disturbancies, autism, Alzheimer’s disease, male infertility, and cardiometabolic problems. Although the amagalm contribution to Mercury release is not so relavant as compared to gold-mining and other sources its use should beggin to be restricted in order to reduce Mercury emissions.A contaminação ambiental e as exposições ocupacionais por mercúrio estão relacionadas a diversos problemas de saúde desde o período fetal. Pelo fato do amálgama ser um material restaurador amplamente usado em odontologia, em virtude da sua facilidade de utilização e do baixo custo, o objetivo deste trabalho foi elaborar uma revisão bibliográfica sobre os aspectos ambientais, ocupacionais e toxicológicos da contaminação mercurial. Foi realizada uma revisão utilizando as bases de dados Medline, ISI e LILACS cobrindo o período de 2004 a 2015. O mercúrio está relacionado à redução do crescimento ponderal e desenvolvimento cognitivo de crianças, bem como a distúrbios psico-afetivos, autismo, doença de Alzheimer, infertilidade masculina e problemas cardiometabólicos. Embora a contribuição das amálgamas dentárias para a liberação de mercúrio não seja tão expressiva comparada à contaminação por atividades de garimpo e outras fontes, seu uso deve começar a ser restrito para reduzir as emissões de mercúrio

Scaling in Athletic World Records

World records in athletics provide a measure of physical as well as physiological human performance. Here we analyse running records and show that the mean speed as a function of race time can be described by two scaling laws that have a breakpoint at about 150-170 seconds (corresponding to the ~1,000 m race). We interpret this as being the transition time between anaerobic and aerobic energy expenditure by athletes.Comment: published in the Brief Communication section of Natur

Glucose pulse. A simple method to estimate the amount of glucose oxidized during exercise in type 1 diabetic patients

In type 1 diabetic patients, exercise contributes to enhance insulin sensitivity and may help, together with diet and insulin therapy, to achieve and maintain better metabolic control. Fat and carbohydrates are the main substrates for energy production in skeletal muscle during aerobic exercise in well-fed humans, with their relative contribution to total energy production being a function of exercise intensity. Below the anaerobic threshold, both oxygen consumption and heart rate during exercise increase linearly as a function of exercise intensity. On the basis of these relationships, the aim of the present study was to verify the possibility of using heart rate to estimate the amount of glucose oxidized during exercise in type 1 diabetic patients as well as in a control group of healthy subjects. This study shows that heart rate can be a useful physiological parameter to be used to estimate the amount of glucose oxidized during exercise

Positive energy balance is associated with accelerated muscle atrophy and increased erythrocyte glutathione turnover during 5 wk of bed rest

Background: Physical inactivity is often associated with positive energy balance and fat gain. Objective: We aimed to assess whether energy intake in excess of requirement activates systemic inflammation and antioxidant defenses and accelerates muscle atrophy induced by inactivity. Design: Nineteen healthy male volunteers were studied before and at the end of 5 wk of bed rest. Subjects were allowed to spontaneously adapt to decreased energy requirement (study A, n = 10) or were provided with an activity-matched diet (study B, n = 9). Groups with higher (HEB) or lower (LEB) energy balance were identified according to median values of inactivity-induced changes in fat mass (\u394FM, assessed by bioelectrical impedance analysis). Results: In pooled subjects (n = 19; median \u394FM: 1.4 kg), bed rest-mediated decreases in fat-free mass (bioelectrical impedance analysis) and vastus lateralis thickness (ultrasound imaging) were significantly greater (P < 0.03) in HEBAB (-3.8 \ub1 0.4kg and -0.32 \ub1 0.04 cm, respectively) than in LEBab (-2.3 \ub1 0.5 kg and -0.09 \ub1 0.04 cm, respectively) subjects. In study A (median \u394FM: 1.8 kg), bed rest-mediated increases in plasma leptin, C-reactive protein, and myeloperoxidase were greater (P < 0.04) in HEBA than in LEBA subjects. Bed rest-mediated changes of glutathione synthesis rate in eythrocytes (L-[3,3-2H2]cysteine incorporation) were greater (P = 0.03) in HEBA (from 70 \ub1 19 to 164 \ub1 29%/d) than in LEBA (from 103 \ub1 23 to 84 \ub1 27%/d) subjects. Conclusions: Positive energy balance during inactivity is associated with greater muscle atrophy and with activation of systemic inflammation and of antioxidant defenses. Optimizing caloric intake may be a useful strategy for mitigating muscle loss during period of chronic inactivity

Pilot investigation of the oxygen demands and metabolic cost of incremental shuttle walking and treadmill walking in patients with cardiovascular disease

Objective: To determine if the metabolic cost of the incremental shuttle-walking test protocol is the same as treadmill walking or predicted values of walking-speed equations. Setting: Primary care (community-based cardiac rehabilitation). Participants: Eight Caucasian cardiac rehabilitation patients (7 males) with a mean age of 67±5.2 years. Primary and secondary outcome measures: Oxygen consumption, metabolic power and energy cost of walking during treadmill and shuttle walking performed in a balanced order with 1 week between trials. Results: Average overall energy cost per metre was higher during treadmill walking (3.22±0.55 J kg/m) than during shuttle walking (3.00±0.41 J kg/m). There were significant post hoc effects at 0.67 m/s (p<0.004) and 0.84 m/s (p<0.001), where the energy cost of treadmill walking was significantly higher than that of shuttle walking. This pattern was reversed at walking speeds 1.52 m/s (p<0.042) and 1.69 m/s (p<0.007) where shuttle walking had a greater energy cost per metre than treadmill walking. At all walking speeds, the energy cost of shuttle walking was higher than that predicted using the American College of Sports Medicine walking equations. Conclusions: The energetic demands of shuttle walking were fundamentally different from those of treadmill walking and should not be directly compared. We warn against estimating the metabolic cost of the incremental shuttle-walking test using the current walking-speed equations

Universality, limits and predictability of gold-medal performances at the Olympic Games

Inspired by the Games held in ancient Greece, modern Olympics represent the world's largest pageant of athletic skill and competitive spirit. Performances of athletes at the Olympic Games mirror, since 1896, human potentialities in sports, and thus provide an optimal source of information for studying the evolution of sport achievements and predicting the limits that athletes can reach. Unfortunately, the models introduced so far for the description of athlete performances at the Olympics are either sophisticated or unrealistic, and more importantly, do not provide a unified theory for sport performances. Here, we address this issue by showing that relative performance improvements of medal winners at the Olympics are normally distributed, implying that the evolution of performance values can be described in good approximation as an exponential approach to an a priori unknown limiting performance value. This law holds for all specialties in athletics-including running, jumping, and throwing-and swimming. We present a self-consistent method, based on normality hypothesis testing, able to predict limiting performance values in all specialties. We further quantify the most likely years in which athletes will breach challenging performance walls in running, jumping, throwing, and swimming events, as well as the probability that new world records will be established at the next edition of the Olympic Games.Comment: 8 pages, 3 figures, 1 table. Supporting information files and data are available at filrad.homelinux.or

Sarcopenia parameters in active older adults - an eight-year longitudinal study

BACKGROUD: Sarcopenia is a common skeletal muscle syndrome that is common in older adults but can be mitigated by adequate and regular physical activity. The development and severity of sarcopenia is favored by several factors, the most influential of which are a sedentary lifestyle and physical inactivity. The aim of this observational longitudinal cohort study was to evaluate changes in sarcopenia parameters, based on the EWGSOP2 definition in a population of active older adults after eight years. It was hypothesized that selected active older adults would perform better on sarcopenia tests than the average population. METHODS: The 52 active older adults (22 men and 30 women, mean age: 68.4 ± 5.6 years at the time of their first evaluation) participated in the study at two time points eight-years apart. Three sarcopenia parameters were assessed at both time points: Muscle strength (handgrip test), skeletal muscle mass index, and physical performance (gait speed), these parameters were used to diagnose sarcop0enia according to the EWGSOP2 definition. Additional motor tests were also performed at follow-up measurements to assess participants' overall fitness. Participants self-reported physical activity and sedentary behavior using General Physical Activity Questionnaire at baseline and at follow-up measurements. RESULTS: In the first measurements we did not detect signs of sarcopenia in any individual, but after 8 years, we detected signs of sarcopenia in 7 participants. After eight years, we detected decline in ; muscle strength (-10.2%; p < .001), muscle mass index (-5.4%; p < .001), and physical performance measured with gait speed (-28.6%; p < .001). Similarly, self-reported physical activity and sedentary behavior declined, too (-25.0%; p = .030 and - 48.5%; p < .001, respectively). CONCLUSIONS: Despite expected lower scores on tests of sarcopenia parameters due to age-related decline, participants performed better on motor tests than reported in similar studies. Nevertheless, the prevalence of sarcopenia was consistent with most of the published literature. TRIAL REGISTRATION: The clinical trial protocol was registered on ClinicalTrials.gov, identifier: NCT04899531

Quantifying The External And Internal Loads Of Professional Rugby League Training Modes: Consideration For Concurrent Field-Based Training Prescription.

Practitioners prescribe numerous training modes to develop the varied physical qualities professional rugby league players must express during competition. The aim of the current study was to determine how the magnitude of external and internal training load per minute of time differs between modes in professional rugby league players. This data were collected from 17 players across 716 individual sessions (mean (SD) sessions: 42 (13) per player) which were categorised by mode (conditioning, small sided games, skills and sprint training). Derived from global positioning systems (5Hz with 15Hz interpolation), the distances covered within arbitrary speed- and metabolic-power-thresholds were determined to represent the external load. Session rating of perceived exertion (sRPE) and individualised training impulse (iTRIMP) represented the internal load. All data were made relative to session duration. The differences in time-relative load methods between each mode were assessed using magnitude based inferences. Small-sided-games and conditioning very likely to almost certainly produced the greatest relative internal and external loads. Sprint training provided players with the greatest sprinting and maximal-power distances without a concomitant increase in internal load. The metabolic-power method complements speed-based quantification of the external load, particularly during smallsided-games and skills training. In practice, establishing normative loads per minute of time for each mode can be useful to plan future training by multiplying this value by the planned session duration