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Fatigue is a common and debilitating symptom among older adults, significantly impacting their quality of life and functional capacity. The relationship between serotonin and fatigue in aging is complex, involving multiple neurobiological pathways that influence sleep, mood, cognitive function, and energy metabolism. Understanding these mechanisms is crucial for developing effective management strategies. This review aims to elucidate the role of serotonin in the development of fatigue in elderly individuals and evaluate potential therapeutic strategies to mitigate this condition. A comprehensive review of recent literature was conducted, focusing on the neurobiological mechanisms linking serotonin to fatigue, the efficacy of pharmacological and non-pharmacological interventions, and future research directions. Studies were selected based on their relevance to serotonin’s role in aging and fatigue management. Serotonin plays a critical role in regulating various physiological and psychological functions that impact fatigue. Age-related declines in serotonin synthesis, receptor sensitivity, and transporter function contribute to increased fatigue through disrupted sleep, mood disorders, cognitive decline, and altered energy metabolism. Pharmacological treatments, including selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), have shown efficacy in alleviating fatigue related to depression and chronic pain. Non-pharmacological interventions, such as cognitive behavioral therapy (CBT), exercise, sleep hygiene, and dietary modifications, are also effective in managing fatigue. Combining these approaches may offer the best outcomes for elderly patients. Addressing fatigue in older adults requires a multifaceted approach that integrates both pharmacological and non-pharmacological strategies. Personalized treatment plans considering individual patient profiles and preferences can enhance therapeutic efficacy. Future research should focus on exploring novel therapeutic targets within the serotonergic system, developing personalized medicine approaches, and evaluating the long-term impact of combined therapies.

The aim of this research was to determine the relationship among transformational leadership style with organizational culture and organizational commitment. The population consists of 745 the employees of the Ministry of Youth and Sports of Iran. The sample size of 256 staffs was determined using stratified random sampling. In order to collect the needed data, three Transformational Leadership, Organizational Culture and Organizational Commitment Questionnaires were used. The validity of these questionnaires was confirmed by foreign and domestic researches. Cronbach's alpha reliability test of transformational leadership, organizational culture and organizational commitment were respectively 0.97, 0.97, and 0.92. In addition, data were analyzed using statistical tests such as descriptive statistics, Kolmogorov Smirnoff, Pearson correlation coefficients using SPSS Software. The findings of this study showed that there was a positive and significant relationship between transformational leadership and organizational culture (p≤0.01, r= 0.80). Besides, there was a positive and significant relationship between transformational leadership and organizational commitment (p≤0.01, r= 0.46), too. Likewise, there was a positive and significant relationship between organizational culture and organizational commitment (p≤0.01, r= 0.57). However, organizational culture is stronger predictor than transformational leadership for organizational commitment. Finally, in accordance with the responses of staffs of the Ministry of Youth and Sports, it can be said that if leaders create an organizational culture in which creativity and satisfaction were high as well as to taking advantage the organizational rewards and job good conditions, employees would be able to stimulate higher levels of organizational commitment.

This review article elucidates the structure and critiques the effects of social loafing in the team sport of volleyball. Drawing upon existing theories, opinions, and research, this review addresses the conceptual framework and factors influencing individual and group behaviors in sports environments, particularly volleyball. These factors include team cohesion, leadership styles, communication, interdependent tasks, and individual motivation. An examination of the research methodologies and article formulations, as well as meta-analyses in academic databases like PubMed, Google Scholar, and PsycINFO, indicates that the predominant approach in studies on this phenomenon is deductive, with survey strategies employed through observational studies and interviews with players and coaches using questionnaires. The findings of this review, on one hand, present and analyze theories and models explaining social loafing behaviors in sports environments and teams, including the processes and dimensions of the emergence (and growth) of social loafing and its impact on individual aspects and team performance in volleyball. On the other hand, it highlights key points and related solutions for future research directions in volleyball, including strategies and interventions (by coaches and team leadership) aimed at reducing social loafing, enhancing cohesion, and improving group dynamics in volleyball teams, ultimately leading to improved team performance.

Background and purpose: Physical activity is effective on the serum level of the monoamine neurotransmitter dopamine and also reduces psychological disorders such as depression. The aim of this study was to investigate the effect of eight weeks of walking on plasma levels of dopamine and the level of depression in elderly women with Alzheimer's disease. Method: In this semi-experimental study, 20 women with Alzheimer's disease with an average age of 73.5 ± 7.72 years who were suffering from moderate to severe depression according to the Beck questionnaire with the opinion of a psychiatrist in a targeted manner and the sample available for were selected to participate in the research. The subjects were randomly divided into two equal groups of 10 people, including the experimental group (walking) and the control group (without regular physical activity). The subjects in the walking group exercised on the treadmill for eight weeks three sessions per week and each session lasted 30-45 minutes with an intensity of 60-75% of the maximum heart rate. Before and after the exercise intervention, blood samples were taken from the cubital vein of all participants in a 12-hour fasting state. Serotonin and dopamine levels were evaluated by ELISA method. The results were extracted using the paired t test and covariance at a significance level of 0.5. Findings: 8 weeks of walking led to a significant increase in dopamine levels (p=0.005) and a significant decrease in depression (p=0.001) in the experimental group compared to the control group. Conclusion: It seems that walking can have positive effects on some neurotransmitters and reduce the level of depression in elderly women with Alzheimer's disease.

Purpose: Delayed onset muscle soreness (DOMS) is pain and stiffness that occurs several hours to several days after unusual or intense exercise. It is thought that this exercise causes small damage (micro trauma) to muscle fibers. The aim of the present study was to compare the effects of high-intensity resistance training and resistance retraining on serum levels of some indices of muscle damage in inactive young girls. Method: Twenty-four healthy inactive young girls voluntarily participated in the present study. They then randomly divided into two groups of 10. The muscle injury protocol included five stations of biceps and shoulder presses with a barbell, squats, chest press, and leg press. Each movement consisted of three sets of 8 to 12 repetitions, with an intensity of 75% of one repetition maximum. Serum levels of creatine kinase, lactate dehydrogenase, and aspartate aminotransferase enzymes were measured before the activity and at intervals of 1, 26, and 48 hours after it. Analysis of variance with repeated measures and independent t-test were used to analyze the data at a significance level of p≥0.05. Results: there was no significant difference in the changes in creatine kinase, lactate dehydrogenase, and aspartate aminotransferase between the two groups at different stages of measurement after retraining (p<0.05). Conclusion: According to the results of the present study, it can be concluded that resistance training cannot be a significant influencing variable on the amount of muscle damage. However, more research in this field is needed.

The present research examines the relationship between metacognitive beliefs and anxiety sensitivity with conscientiousness of lifeguards. This is a descriptive-correlational research and has been carried out by the field method. The statistical population of the research included all female lifeguards in the east of the country and at different work levels (310 people). Next, according to the type of statistical population, the sample size was calculated using Morgan's table to the number of 150 people, and they completed the questionnaires of metacognitive beliefs, anxiety sensitivity and conscientiousness. Data were analyzed through Pearson correlation and multiple regression statistical tests simultaneously. The results showed that there is a significant correlation between metacognitive beliefs and anxiety sensitivity with conscientiousness (p≤0.05). Positive metacognitive beliefs have a positive and significant relationship with conscientiousness, while the relationship between negative metacognitive beliefs and anxiety sensitivity with conscientiousness is negative and significant. Since lifeguards should be at the peak of responsibility, knowing the issues that can negatively affect their conscientiousness can be a solution or suggestion to improve their performance. Therefore, according to the results of the research, it is suggested to discuss the psychological preparation of lifeguards, especially in the cognitive aspect. There should be more emphasis