Cortisol Reactivity to a physical stressor in Patients with Depression and Alzheimer's disease.

Some prevalent mental disorders in the elderly, such as Alzheimer's disease (AD) and major depression disorder (MDD), are associated with chronic stress and consequently with possible dysregulation of hypothalamic-pituitary-adrenal (HPA) axis and cortisol levels in basal conditions or in the reactivity of an acute stressor. However, evidence of cortisol behavior after a physical stressor in patients with AD and MDD is scarce. Objective: This study aimed to investigate the cortisol reactivity to a single session of physical exercise in patients with MDD and AD and compare it to healthy control (HC) older individuals. Methods: HC individuals (n=10) and elderly with clinical diagnostic of MDD (n=08) and AD (n=13) were submitted to a single bout of aerobic exercise in a treadmill during 30 minutes of moderate intensity. Salivary cortisol was collected before and after acute stressor. A repeated-measure analysis of variance (ANOVA), spearman correlation, and linear regression were performed. Results: The repeated-measure ANOVA revealed no interaction for cortisol on the moment×group [F(2.000, 28.000)=1.285; p=0.293] and no effect for group (F=0.323; p=0.727). However, a significant effect for moment [F(1.000, 28.000)=4.930; p=0.035] was found, with a decreased cortisol levels in postexercise for all groups. The effect size (ES) of cortisol reduction was small for patients with MDD (d=0.402) and trivial for patients with AD (d=0.166) and HC group (d=0.090). Conclusions: All participants show a decreased cortisol reactivity to a physical stressor, which can be associated with an impairment in coping with an acute stressor.

A doença de Alzheimer (DA) e o transtorno depressivo maior (TDM) são transtornos que acometem idosos e estão associadas ao estresse crônico e à desregulação do eixo hipotálamo-hipófise-adrenal (HPA), que repercute em alterações nos níveis de cortisol (basal e reatividade). Objetivo: Investigar a reatividade do cortisol em uma única sessão de exercício físico em pacientes com TDM e com DA e compará-la com a de idosos saudáveis. Métodos: Indivíduos controle saudáveis (n=10) e idosos com diagnóstico clínico de TDM (n=08) e DA (n=13) foram submetidos a uma única sessão de exercício aeróbio em esteira rolante, durante 30 minutos, em intensidade moderada. O cortisol salivar foi coletado antes e depois do estressor agudo. Na estatística, foram realizadas as análises de variância (ANOVA) de medidas repetidas, correlação de spearman e regressão linear. Resultados: Não foi encontrada interação para momento x grupo [F (2.000, 28.000)=1.285; p=0,293] e tampouco efeito para o grupo (F=0,323; p=0,727). Todavia, foi observado efeito significativo para o momento [F(1,000, 28,000)=4,930; p=0,035], mostrando diminuição dos níveis de cortisol no pós-exercício para todos os grupos. O tamanho do efeito (TE) foi considerado pequeno para o grupo TDM (d=0,402) e trivial para o DA (d=0,166) e o saudável (d=0,090). Conclusões: Todos os participantes apresentaram diminuição da reatividade do cortisol a um estressor físico, o que pode estar associado a um comprometimento no enfrentamento de um estressor agudo.

Is Strength Training as Effective as Aerobic Training for Depression in Older Adults? A Randomized Controlled Trial.

BACKGROUND: This study aimed to compare the effects of aerobic training (AT), strength training (ST) and low-intensity exercise in a control group (CG) as adjunct treatments to pharmacotherapy for major depressive disorder (MDD) in older persons. METHODS: Older persons clinically diagnosed with MDD (n = 27) and treated with antidepressants were blindly randomized into three groups: AT, ST and a CG. All patients were evaluated prior to and 12 weeks after the intervention. RESULTS: Compared with the CG, the AT and ST groups showed significant reductions in depressive symptoms (treatment -response = 50% decrease in the pre- to postintervention assessment) through the Hamilton Depression Rating Scale (AT group: χ2, p = 0.044) and Beck Depression Inventory (ST group: χ2, p = 0.044). CONCLUSION: Adding AT or ST with moderate intensity to the usual treatment promoted a greater reduction of MDD symptoms.

Behavior of Heart Rate Variability After 10 Repetitions Maximum Load Test for Lower Limbs.

The purpose of this study was to analyze the acute heart rate variability behavior after 10 repetitions maximum load test for back squat, leg press, leg extension, and leg flexion in normotensive subjects. Eight recreationally trained women (age: 21.8 ± 2.2 yrs; height: 167.6 ± 6.3 cm; weight: 61.6 ± 10.1 kg) performed two 10 repetitions maximum testing days with 48-hours rest between each one. Heart rate variability was measured in baseline and postexercise (15-, 30-, 45-, and 60-minutes) for time and frequency domain. A significant difference was identified in RMSSDms (p = 0.010; effect size = -1.3), MRRms (p = 0.026; effect size = -1.3), MHR (p = 0.006; effect size = 1.4), and PNN50% (p = 0.006; effect size = -1.6) when compared 15 minutes postexercise with baseline. For all others comparison and index were no differences (p > 0.05). The present study demonstrates that load test, although works with maximum intensities, did not generate an exacerbated postexercise sympathetic activity. Thus, it seems to be safe for cardiovascular healthy individuals. As a practical application, these results can encourage exercise practitioners to do a maximum load test to resistance training loads prescription.

Effect of Exercise on Inflammatory Profile of Older Persons: Systematic Review and Meta-Analyses.

BACKGROUND: Inflammatory cytokines and acute phase proteins increase with aging, promoting a chronic low-grade inflammation. Studies have shown a positive effect of exercise on inflammatory markers in older persons. Interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP) are the main biomarkers investigated. However, it is unclear if exercise could decrease all these biomarkers. PURPOSE: The aim was to analyze the effect of chronic exercise on IL-6, TNF-α, and CRP levels in older persons. METHODS: Preferred Reporting Items in Systematic Reviews and Meta-analyses guidelines were adopted. Original articles that investigated the effect of chronic exercise on inflammatory profile of the elderly persons were eligible for this review. The databases PubMed, PEDro, EBSCO, and BioMed Central were searched. Three reviewers evaluated each publication for reducing bias. Data about IL-6, TNF-α, and CRP were collected and analyzed. A standardized mean difference based on estimated pooled effect size was calculated considering heterogeneity index (I2) and random effect. RESULTS: Seventy-six studies were retrieved from databases, and 8 of them were analyzed. IL-6 and CRP levels decreased after chronic exercise (overall effect P < .05). CONCLUSION: Regular exercise decreases IL-6 and CRP levels in older persons. The effect of exercise on TNF-α remains unclear.

Analysis of reliability of peak treadmill running in maximum progressive effort test: influence of training level / Análise de confiabilidade da velocidade pico em teste de esforço progressivo máximo: influência do nível de treinamento

OBJECTIVE: To determine the reliability (stability) of the peak velocity measurement (VPeak) derived from the incremental maximal effort test, as well as to establish the possible influence of the level of training on these responses. METHOD: Thirty-eight male volunteers made two visits (3 - 5 days apart) to the training center where the study was conducted and performed maximal progressive running tests. The protocol consisted of increments of 0.5 km.h-1/min, starting at a running speed comfortable for each participant (7-9 km.h-1). All subjects were encouraged to achieve the maximum possible performance in both tests, with final voluntary exhaustion being the criterion for interruption. RESULTS: The intra-class correlation coefficient presented excellent consistency of measurements (ICC = 0.975 - p = 0.001). The typical relative error of the measurement was 2.6% for the stability of the measurement of VPeak. Moreover, there were no significant differences between the individual coefficients of variation for measures 1 vs. 2 (p > 0.05). Graphical representation of Bland-Altman demonstrated a homogeneous distribution of the measurement error for all dependent variables. CONCLUSION: Determination of VPeak exhibited excellent levels of reliability with small measurement errors. There was no influence of the training level on the reliability responses.

OBJETIVO: Determinar a confiabilidade (estabilidade) da medida de velocidade de pico (VPico) derivada do teste incremental de esforço progressivo máximo, bem como estabelecer a possível influência do nível de treinamento sobre estas respostas. MÉTODO: Trinta e oito voluntários fizeram duas visitas ao centro de treinamento com intervalo de três a cinco dias. Na primeira visita os voluntários assinaram um termo de consentimento, tiveram suas medidas antropométricas registradas e realizaram a primeira sessão de corrida progressiva máxima. Na segunda visita o teste progressivo máximo foi novamente realizado. O protocolo consistiu em incrementos de 0,5 km.h-1 a cada min iniciando a uma velocidade individual de corrida classificada como confortável por cada participante (7 a 9 km.h-1). Todos os participantes foram encorajados a alcançar o máximo de desempenho possível em ambos os testes, tendo como critério de finalização, a exaustão voluntária máxima. RESULTADO: O coeficiente de correlação intra-classe (CCI) apresentou excelente consistência da medida (0,975) para VPico (p = 0,001). O erro típico relativo da medida foi de 2,6% para a estabilidade da medida de VPico. Não foram observadas diferenças significativas entre os coeficientes de variação individuais para as medidas G1 vs. G2 (p > 0,05). A representação gráfica de Bland-Altman demonstrou distribuição homogênea do erro da medida para todas as variáveis dependentes. CONCLUSÃO: A determinação da VPico exibiu excelentes níveis de confiabilidade, com pequenos erros de medida. Não houve influência do nível de treinamento sobre as respostas de confiabilidade.

Acute Affective Responses and Frontal Electroencephalographic Asymmetry to Prescribed and Self-selected Exercise.

OBJECTIVE: Our goal was to compare affective responses and frontal electroencephalographic alpha asymmetry induced by prescribed exercise (PE) and self-selected exercise (SS). METHOD: Twenty active participants underwent a submaximal exercise test to estimate maximal oxygen consumption (VO2max). Participants enrolled a cross-over randomized study where each participant completed three conditions: PE (50%PVO2max), SS and Control. The electroencephalography was performed before and after exercise. The feeling scale, felt arousal scale and heart rate were recorded before, during and after each condition. The ratings of perceived exertion were recorded during and after each condition. RESULTS: The heart rate and ratings of perceived exertion showed higher values in the PE and SS conditions compared to controls, with no differences between the PE and SS conditions. For the feeling scale, the SS presented higher values compared to the PE and Control conditions. The felt arousal scale presented higher values in the PE and SS conditions compared to control. There was no interaction between condition and moment, or main effect for condition and moment for frontal alpha asymmetry (InF4-InF3). CONCLUSION: The SS provided better affective responses compared to PE, thus can consider self-selected intensity as an appropriate option. In general, no frontal alpha asymmetry was seen due to an exercise intervention.

From Mind to Body: Is Mental Practice Effective on Strength Gains? A Meta-Analysis.

Mental practice is an internal reproduction of a motor act (whose intention is to promote learning and improving motor skills). Some studies have shown that other cognitive strategies also increase the strength and muscular resistance in healthy people by the enhancement of the performance during dynamic tasks. Mental training sessions may be primordial to improving muscle strength in different subjects. The aim of this study was to systematically review and meta-analiyze studies that assessed whether mental practice is effective in improving muscular strength. We conducted an electronic-computed search in Pub-Med/Medline and ISI Web of Knowledge, Scielo and manual searchs, searching papers written in English between 1991 and 2014. There were 44 studies in Pub-Med/Medline, 631 in ISI Web of Knowledge, 11 in Scielo and 3 in manual searchs databases. After exclusion of studies for duplicate, unrelated to the topic by title and summary, different samples and methodologies, a meta-analysis of 4 studies was carried out to identify the dose-response relationship. We did not find evidence that mental practice is effective in increasing strength in healthy individuals. There is no evidence that mental practice alone can be effective to induce strength gains or to optimize the training effects.

Aging process, cognitive decline and Alzheimer`s disease: can strength training modulate these responses?

Some evidence shows that aerobic training can attenuate the aging effects on the brain structures and functions. However, the strength exercise effects are poorly discussed. Thus, in the present study, the effects of strength training on the brain in elderly people and Alzheimer`s disease (AD) patients were revised. Furthermore, it a biological explanation relating to strength training effects on the brain is proposed. Brain atrophy can be related to neurotransmission dysfunction, like oxidative stress, that generates mitochondrial damage and reduced brain metabolism. Another mechanism is related to amyloid deposition and amyloid tangles, that can be related to reductions on insulin-like growth factor I concentrations. The brain-derived neurotrophic factor also presents reduction during aging process and AD. These neuronal dysfunctions are also related to cerebral blood flow decline that influence brain metabolism. All of these alterations contribute to cognitive impairment and AD. After a long period of strength training, the oxidative stress can be reduced, the brain-derived neurotrophic factor and insulin-like growth factor I serum concentrations enhance, and the cognitive performance improves. Considering these results, we can infer that strength training can be related to increased neurogenesis, neuroplasticity and, consequently, counteracts aging effects on the brain. The effect of strength training as an additional treatment of AD needs further investigation.

AFFECTIVE RESPONSES TO PRESCRIBED AND SELF-SELECTED STRENGTH TRAINING INTENSITIES.

This study was an evaluation of the effects of self-selected intensity and three prescribed intensities of strength exercises on affective responses. 16 healthy active male participants (M age = 25.1 yr., SD = 5.5; M height = 168.0 cm, SD = 31.8; M weight = 84.4 kg, SD = 8.6) were randomly assigned to a control condition without exercise (Control); three prescribed exercise intensities at 40% of one-repetition maximum (1RM), 60% 1RM, and 80% 1RM; and one self-selected intensity (Self-selected). Affective response was assessed by the Feeling Scale and the Felt Arousal Scale. All prescribed intensities showed increased activation and only the session at 80% 1RM showed reduction valence compared to the Control condition. Thus, the affective response to strength training does not seem to be influenced by exercise intensity.

We need to move more: Neurobiological hypotheses of physical exercise as a treatment for Parkinson's disease.

Parkinson's disease (PD) is one of the most prevalent neurodegenerative diseases in the world. The degeneration of dopaminergic neurons in the substantia nigra and chronic inflammation impair specific brain areas, which in turn result in lesser motor control, behavioral changes and cognitive decline. Nowadays, drug-treatments are the foremost approaches in treating PD. However, exercise has been shown to have powerful effects on PD, based on several neurobiological mechanisms. These effects may decrease the risk of developing PD by 33%. However, these mechanisms are unclear and little explored. Among several mechanisms, we propose two specific hypotheses: 1. Physical exercise reduces chronic oxidative stress and stimulates mitochondria biogenesis and up-regulation of authophagy in PD patients. Moreover, antioxidant enzymes (e.g. superoxide dismutase) become more active and effective in response to physical exercise. 2. Exercise stimulates neurotransmitter (e.g. dopamine) and trophic factors (BDNF, GDNF, FGF-2, IGF-1, among others) synthesis. These neurochemical phenomena promote neuroplasticity, which, in turn, decreases neural apoptosis and may delay the neurodegeneration process, preventing or decreasing PD development and symptoms, respectively.

Acute effects of exercise on mood and EEG activity in healthy young subjects: a systematic review.

Electroencephalography has been used to establish the relationship among cortical activity, exercise and mood, such as asymmetry, absolute and relative power. The purpose of this study was to systematically review the influence of cortical activity on mood state induced by exercise. The Preferred Reporting Items in Systematic reviews and Meta-Analyses was followed in this study. The studies were retrieved from MEDLINE/PubMed, ISI Web of Knowledge and SciELO. Search was conducted in all databases using the following terms: EEG asymmetry, sLORETA, exercise, with affect, mood and emotions. Based on the defined criteria, a total of 727 articles were found in the search conducted in the literature (666 in Pubmed, 54 in ISI Web of Science, 2 in SciELO and 5 in other data sources). Total of 11 studies were selected which properly met the criteria for this review. Nine out of 11 studies used the frontal asymmetry, four used absolute and relative power and one used sLORETA. With regard to changes in cortical activity and mood induced by exercise, six studies attributed this result to different intensities, one to duration, one to type of exercise and one to fitness level. In general, EEG measures showed contradictory evidence of its ability to predict or modulate psychological mood states through exercise intervention.

Implications of movement-related cortical potential for understanding neural adaptations in muscle strength tasks.

This systematic review aims to provide information about the implications of the movement-related cortical potential (MRCP) in acute and chronic responses to the counter resistance training. The structuring of the methods of this study followed the proposals of the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses). It was performed an electronically search in Pubmed/Medline and ISI Web of Knowledge data bases, from 1987 to 2013, besides the manual search in the selected references. The following terms were used: Bereitschaftspotential, MRCP, strength and force. The logical operator "AND" was used to combine descriptors and terms used to search publications. At the end, 11 studies attended all the eligibility criteria and the results demonstrated that the behavior of MRCP is altered because of different factors such as: force level, rate of force development, fatigue induced by exercise, and the specific phase of muscular action, leading to an increase in the amplitude in eccentric actions compared to concentric actions, in acute effects. The long-term adaptations demonstrated that the counter resistance training provokes an attenuation in the amplitude in areas related to the movement, which may be caused by neural adaptation occurred in the motor cortex.

Neuroscience of exercise: from neurobiology mechanisms to mental health.

The neuroscience of exercise is a growing research area that is dedicated to furthering our understanding of the effects that exercise has on mental health and athletic performance. The present study examined three specific topics: (1) the relationship between exercise and mental disorders (e.g. major depressive disorder, dementia and Parkinson's disease), (2) the effects of exercise on the mood and mental health of athletes, and (3) the possible neurobiological mechanisms that mediate the effects of exercise. Positive responses to regular physical exercise, such as enhanced functional capacity, increased autonomy and improved self-esteem, are frequently described in the recent literature, and these responses are all good reasons for recommending regular exercise. In addition, physical exercise may improve both mood and adherence to an exercise program in healthy individuals and might modulate both the performance and mental health of athletes. Exercise is associated with the increased synthesis and release of both neurotransmitters and neurotrophic factors, and these increases may be associated with neurogenesis, angiogenesis and neuroplasticity. This review is a call-to-action that urges researchers to consider the importance of understanding the neuroscience of physical exercise and its contributions to sports science.

Two-year citations of JAPPL original articles: evidence of a relative age effect.

Several indicators have been used to analyze scientific journals, with the impact factor and the number of citations in a 2-yr calendar time frame (2-YRC) being the most common factors. However, considering that the Journal of Applied Physiology (JAPPL) appears monthly and that calculations of these indicators are based on citations of papers published in previous years, we hypothesized that articles published at the beginning of the year would be cited more in the 2-YRC compared with those appearing in the last issues of the year, a phenomena known as a relative age effect. Our objective was to confirm the existence of a relative age effect in the 2-YRC for original articles published in JAPPL. From 2005 to 2008, a total of 1,726 original articles were published, according to the Web of Science, and 9,973 citations in 2-YRC, varying from 0 to 45, with a mean of 5.78 for individual papers. Although there were no differences in the number of original articles published in a given month (P = 0.99), the 2-YRC varied considerably throughout the year, being higher for those earlier issues of the year, as shown by the linear regression analysis (r(2) = 0.76; P < 0.001). The 2-YRC began at 6.62 during the first 3 mo of the year, dropping by 10% at each 3-mo period. In summary, the longer an article has been out there, the more citations it collects. The relative age effect is a potential confounding variable for the assessment and interpretation of 2-YRC (using calendar years) from JAPPL original articles.