Revealing the drivers of parasite community assembly: using avian haemosporidians to model global dynamics of parasite species turnover

Why do some regions share more or fewer species than others? Community assembly relies on the ability of individuals to disperse, colonize and thrive in new regions. Therefore, many distinct factors, such as geographic distance and environmental features, can determine the odds of a species colonizing a new environment. For parasites, host community composition (i.e. resources) also plays a key role in their ability to colonize a new environment as they rely on their hosts to complete their life cycle. Thus, variation in host community composition and environmental conditions should determine parasite turnover among regions. Here, we explored the global drivers of parasite turnover using avian malaria and malaria-like (haemosporidian) parasites. We compiled global databases on avian haemosporidian lineages distributions, environmental conditions, avian species distributions and functional traits, and ran generalized dissimilarity models to uncover the main drivers of parasite turnover. We demonstrated that haemosporidian parasite turnover is mainly driven by geographic distance followed by host functional traits, environmental conditions and host distributions. The main host functional traits associated with high parasite turnover were the predominance of resident (i.e. non-migratory) species and strong territoriality, while the most important climatic drivers of haemosporidian turnover were mean temperature and temperature seasonality. Overall, we established the importance of geographic distance as a key predictor of ecological dissimilarity and showed that host resources influence parasite turnover more strongly than environmental conditions. We also evidenced that parasite turnover is most pronounced among tropical and less interconnected regions (i.e. regions with mostly territorial and non-migratory hosts). Our findings provide a robust foundation for the prediction of avian pathogen spread and the emergence of infectious diseases.Fil: de Angeli Dutra, Daniela. University of Otago; Nueva ZelandaFil: Barros Pereira Pinheiro, Rafael. Universidade Estadual de Campinas; BrasilFil: Fecchio, Alan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónica. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigación Esquel de Montaña y Estepa Patagónica; ArgentinaFil: Poulin, Robert. University of Otago; Nueva Zeland

Reliability of heart rate variability in futsal players

The main aim the present study was evaluated the reliability of the heart rate variability (HRV) indices in futsal players. Additionally the study verifi ed the reliability of different approaches for 5 min interval selection of recording. Eighteen under-20 futsal players underwent 15 min of pre-training RR interval recordings in two different day. Time and frequency domain and Poincaré Plot indices were tested. The indices were calculated using: 1) fi nal 5 min of recording; 2) 5 min of lower variance of recording, by a mathematical algorithm; 3) 5 min segment of lower variance, by an experienced operator. The HRV indices presented a wide range reliability [e.g. RRmean (ICC=0.96, SEM=3.4ms, CV=2.6%), lnRMSSD (ICC=0.88, SEM=5.9ms, CV=4.3%), lnHF (ICC=0.89, SEM=7.5ms, CV=5.9%), LFnu (ICC=0.84, SEM=13ms, CV=9.4%), LF (ICC=0.47, SEM=65.2ms,CV=38.5%) and LF/HF (ICC=0.63, SEM=83.7ms, CV=54.5%)]. The fi nal 5 min of recording was the most reliable. The results suggest that most of HRV indices presented acceptable reliability, however the RRmean, lnRMSSD, lnHF and LFnu were the most reliable

Reproducibility of hemodynamic, cardiac autonomic modulation and blood flow assessments in patients with intermittent claudication

Objective: To identify, in patients with peripheral artery disease and intermittent claudication (IC), the reproducibility of heart rate (HR), blood pressure (BP), rate pressure product (RPP), heart rate variability (HRV), and forearm and calf blood flow (BF) and vasodilatory assessments. Methods: Twenty-nine patients with IC underwent test and retest sessions, 8-12 days apart. During each session, HR, BP, HRV, BF and vasodilatory responses were measured by electrocardiogram, auscultation, spectral analysis of HRV (low frequency, LFR-R; high frequency, HFR-R) and strain gauge plethysmography (baseline BF, post-occlusion BF, post-occlusion area under the curve, AUC). Reproducibility was determined by intraclass coefficient correlation (ICC), typical error, coefficient of variation (CV) and limits of agreement. Results: The ICC for HR and BP were > 0.8 with CV 0.9 while CV were 0.9 while CV were < 19%; variable ICC and CV for vasodilatory responses were exhibited for calf (0.653 – 0.770; 35.2 – 37.7%) and forearm (0.169 – 0.265; 46.2 – 55.5%). Conclusions: In male patients with IC, systemic hemodynamic (HR and BP), cardiac autonomic modulation (LFR-R and HFR-R) and forearm and calf baseline BF assessments exhibited excellent reproducibility, whereas the level of reproducibility for vasodilatory responses were moderate to poor. Assessment reproducibility has highlighted appropriate clinical tools for the regular monitoring of disease/intervention progression in patients with IC

Potential mechanisms behind the blood pressure–lowering effect of dynamic resistance training

Purpose of Review: To elucidate the hemodynamic, autonomic, vascular, hormonal, and local mechanisms involved in the blood pressure (BP)–lowering effect of dynamic resistance training (DRT) in prehypertensive and hypertensive populations. Recent Findings: The systematic search identified 16 studies involving 17 experimental groups that assessed the DRT effects on BP mechanisms in prehypertensive and/or hypertensive populations. These studies mainly enrolled women and middle-aged/older individuals. Vascular effects of DRT were consistently reported, with vascular conductance, flow-mediated dilation, and vasodilatory capacity increases found in all studies. On the other hand, evidence regarding the effects of DRT on systemic hemodynamics, autonomic regulation, hormones, and vasoactive substances are still scarce and controversial, not allowing for any conclusion. Summary: The current literature synthesis shows that DRT may promote vascular adaptations, improving vascular conductance and endothelial function, which may have a role in the BP-lowering effect of this type of training in prehypertensive and hypertensive individuals. More studies are needed to explore the role of other mechanisms in the BP-lowering effect of DRT

Postexercise hypotension as a clinical tool: a “single brick” in the wall

After an exercise session, a reduction of blood pressure (BP) is expected, a phenomenon called postexercise hypotension (PEH). PEH as a predictor of chronic training responses for BP has been broadly explored. It suggests that when PEH occurs after each exercise sessions, its benefits may summate over time, contributing to the chronic adaptation. Thus, PEH is an important clinical tool, acting as a “single brick” in the wall, and building the chronic effect of decreasing BP. However, there is large variation in the literature regarding methodology and results, creating barriers for understanding comparisons among PEH studies. Thus, the differences among subjects' and exercise protocols’ characteristics observed in the studies investigating PEH must be considered when readers interpret the results. Furthermore, understanding of these factors of influence might be useful for avoiding misinterpretations in future comparisons and how the subjacent mechanisms contribute to the BP reduction after exercise

Comparison of morning versus evening aerobic-exercise training on heart rate recovery in treated hypertensive men: a randomized controlled trial

Heart rate recovery (HRR) is a marker of cardiac autonomic regulation and an independent predictor of mortality. Aerobic-exercise training conducted in the evening (evening training) produces greater improvement in resting cardiac autonomic control in hypertensives than morning training, suggesting it may also result in a faster autonomic restoration postexercise. This study compared the effects of morning training and evening training on HRR in treated hypertensive men. Forty-nine treated hypertensive men were randomly allocated into three groups: morning training, evening training and control. Training was conducted three times/week for 10 weeks. Training groups cycled (45 min, moderate intensity) while control group stretched (30 min). In the initial and final assessments of the study, HRR60s and HRR300s were evaluated during the active recovery (30 W) from cardiopulmonary exercise tests (CPET) conducted in the morning and evening. Between-within ANOVAs were applied (P ≤ 0.05). Only evening training increased HRR60s and HRR300 differently from control after morning CPET (+4 ± 5 and +7 ± 8 bpm, respectively, P < 0.05) and only evening training increased HRR300s differently from morning training and control after evening CPET (+8 ± 6 bpm, P < 0.05). Evening training improves HRR in treated hypertensive men, suggesting that this time of day is better for eliciting cardiac autonomic improvements via aerobic training in hypertensives

A single session of aerobic exercise reduces systolic blood pressure at rest and in response to stress in women with rheumatoid arthritis and hypertension

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease characterized by increased risk of cardiovascular disease and hypertension (HT). A single session of aerobic exercise may reduce blood pressure (BP) in different clinical groups; however, little is known about the acute effects of exercise on BP in RA patients. This is a randomized controlled crossover study that assessed the effects of a single session of aerobic exercise on resting BP, on BP responses to stressful stimuli, and on 24-h BP in women with RA and HT. Twenty women with RA and HT (53 ± 10 years) undertook sessions of 30-min treadmill exercise (50% VO2max) or control (no exercise) in a crossover fashion. Before and after the sessions, BP was measured at rest, and in response to the Stroop-Color Word Test (SCWT), the Cold Pressor Test (CPT), and an isometric handgrip test. After the sessions, participants were also fitted with an ambulatory BP monitor for the assessment of 24-h BP. A single session of exercise reduced resting systolic BP (SBP) (-5 ± 9 mmHg; p < 0.05), and reduced SBP response to the SCWT (-7 ± 14 mmHg; p < 0.05), and to the CPT (-5 ± 11 mmHg; p < 0.05). Exercise did not reduce resting diastolic BP (DBP), BP responses to the isometric handgrip test or 24-h BP. In conclusion, a single session of aerobic exercise reduced SBP at rest and in response to stressful stimuli in hypertensive women with RA. These results support the use of exercise as a strategy for controlling HT and, hence, reducing cardiovascular risk in women with RA.Clinical Trial Registration: This study registered at the Brazilian Clinical Trials ( https://ensaiosclinicos.gov.br/rg/RBR-867k9g ) at 12/13/2019

Unsupervised walking prescription, cardiovascular risk and physical fitness

OBJETIVO: Avaliar, numa situação real de atuação prática, o efeito da prescrição individualizada de caminhada sem supervisão da prática sobre o risco cardiovascular e a aptidão física de usuários de um parque público. MÉTODOS: 186 sujeitos (62 ± 10 anos) foram orientados a caminhar pelo menos 3x/sem, por 30 min, com intensidade de 50 a 80% da frequência cardíaca de reserva e a fazer alongamentos antes e após a caminhada. A aptidão física e os fatores de risco cardiovascular foram avaliados pré e pós-intervenção. A análise dos dados foi dividida em duas fases: 1) análise na amostra total; 2) análise nos indivíduos com fatores de risco alterados. Os dados foram comparados pelo teste t pareado. RESULTADOS: Na amostra total, a aptidão física melhorou nos testes de marcha estacionária (+8,1 ± 14,5 passos, p < 0,05), impulsão vertical (+0,5 ± 2,7 cm, p < 0,05), flexibilidade lombar (+1,1 ± 4,7 cm, p < 0,05) e flexibilidade de ombro (+1,2 ± 2,1 cm, p < 0,05). Não ocorreram alterações nos fatores de risco cardiovascular, com exceção da redução da pressão arterial diastólica (-0,9 ± 6,0 mmHg, p < 0,05). Entretanto, nos subgrupos com fatores alterados, observou-se reduções significantes das pressões arteriais sistólica e diastólica (-13,3 ± 16,9 e -5,8 ± 8,3 mmHg, p < 0,05, respectivamente) nos hipertensos, da colesterolemia total (-19,5 ± 33,5 mg/dl, p < 0,05) nos hipercolesterolêmicos e da circunferência da cintura (-1,0 ± 4,7 cm, p < 0,05) e do índice cintura-quadril (-0,01 ± 0,04, p < 0,05) nos com obesidade central. CONCLUSÃO: Numa situação real de atuação, a prescrição de caminhada sem supervisão da prática foi efetiva em melhorar a aptidão física da amostra geral e em diminuir o risco cardiovascular específico dos indivíduos com fatores de risco.OBJECTIVE: To evaluate, at a real practical condition, the effects of individualized prescription of walking without supervision of practice on cardiovascular risk and fitness in users of a public park. METHODS: One hundred, eighty six subjects (62 ± 10 years) were instructed to walk at least 3 times/week, during 30min, at an intensity of 50-80% of heart rate reserve and encouraged to realize stretching exercises before and after walking. Physical fitness and cardiovascular risk factors were evaluated pre and post-intervention. Data analyze was divided in 2 phases: 1) role sample analysis; and 2) analysis on subjects with altered cardiovascular risk factors. Data were compared by paired t test. RESULTS: Considering the whole sample, physical fitness improved in the following tests: stationary gate (8.1 ± 14.5 paces, p < 0.05), vertical jump (0.5 ± 2.7 cm, p < 0.05), lumbar flexibility (1.1 ± 4.7 cm, p < 0.05) and shoulder flexibility (1.2 ± 2.1 cm, p < 0.05). No significant change was observed in cardiovascular risk factors, excepted by a reduction on diastolic blood pressure (-0.9 ± 6.0 mmHg, p < 0.05). On the other hand, considering the subjects with altered cardiovascular risk factors, a significant reduction was observed on systolic and diastolic blood pressures (-13.3 ± 16.9 and -5.8 ± 8.3 mmHg, p < 0.05, respectively) in hypertensive subjects, on total cholesterol (-19.5 ± 33.5 mg/dl, p < 0.05) in hypercholesterolemic subjects, and on waist circumference (-1.0 ± 4.7 cm, p < 0.05) and waist-hip index (0.01 ± 0.04, p < 0.05) in subjects with central obesity. CONCLUSION: Under real practical circumstances, the prescription of unsupervised walking was effective in improving physical fitness in general sample and in reducing the specific cardiovascular risk in subjects who have altered cardiovascular risk factors

Reproducibility of post-exercise heart rate recovery indices: a systematic review

Heart rate recovery (HRR) has been widely used to evaluate the integrity of the autonomic nervous system with a slower HRR being associated with greater cardiovascular risk. Different HRR indices have been proposed. Some evaluate HR changes from the end of exercise to a specific recovery moment (e.g. 60s – HRR60s; 120s – HRR120s; 300s – HRR300s) and others calculate time-constant decays of HR for different recovery intervals (e.g. first 30s – T30; the entire period – HRRt). Several studies have examined the reproducibility of these commonly-used HRR indices, but reported discordant findings. Thus, this systematic review was designed to synthesize the reproducibility of HRR. We included studies that evaluated short-term (<1 year) reproducibility of HRR after dynamic exercise by employing typical measures of reliability (intraclass correlation coefficient, ICC) and agreement (coefficient of variation, CV). The electronic database PubMed/Medline was searched for relevant studies published up to July 2018. From the initial 120 records identified, 15 studies were retained for the qualitative synthesis of 24 experimental conditions. During most experimental conditions, high ICC and desirable CV were reported for HRR60s (62.5 and 76.2%, respectively), HRR120s (55.6 and 71.4%) and HRR300s (50.0 and 100.0%). While, it were reported during the minority of conditions for HRRt (37.5 and 42.9%) and in none condition for T30 (0.0 and 0.0%). In conclusion, HRR60s, HRR120s and HRR300s exhibited good reproducibility for evaluating HRR in predominantly healthy males within research and clinical settings. In contrast, caution should be taken when employing other HRR indices (T30, HRRt) due to their poorer reproducibility

Poor sleep quality is associated with cardiac autonomic dysfunction in treated hypertensive men

Hypertensives present cardiac autonomic dysfunction. Reduction in sleep quality increases blood pressure (BP) and favors hypertension development. Previous studies suggested a relationship between cardiovascular autonomic dysfunction and sleep quality, but it is unclear whether this association is present in hypertensives. Thus, this study evaluated the relationship between sleep quality and cardiac autonomic modulation in hypertensives. Forty‐seven middle‐aged hypertensive men under consistent anti‐hypertensive treatment were assessed for sleep quality by the Pittsburgh Sleep Quality Index (PSQI—higher score means worse sleep quality). Additionally, their beat‐by‐beat BP and heart rate (HR) were recorded, and cardiac autonomic modulation was assessed by their variabilities. Mann‐Whitney and t tests were used to compare different sleep quality groups: poor (PSQI > 5, n = 24) vs good (PSQI ≤ 5, n = 23), and Spearman’s correlations to investigate associations between sleep quality and autonomic markers. Patients with poor sleep quality presented lower cardiac parasympathetic modulation (HR high‐frequency band = 26 ± 13 vs 36 ± 15 nu, P = .03; HR total variance = 951 ± 1373 vs 1608 ± 2272 ms(2), P = .05) and cardiac baroreflex sensitivity (4.5 ± 2.3 vs 7.1 ± 3.7 ms/mm Hg, P = .01). Additionally, sleep quality score presented significant positive correlation with HR (r = +0.34, P = .02) and negative correlations with HR high‐frequency band (r = −0.34, P = .03), HR total variance (r = −0.35, P = .02), and cardiac baroreflex sensitivity (r = −0.42, P = .01), showing that poor sleep quality is associated with higher HR and lower cardiac parasympathetic modulation and baroreflex sensitivity. In conclusion, in treated hypertensive men, poor sleep quality is associated with cardiac autonomic dysfunction