The influence of physical fitness and exercise upon cognitive functioning
It is well know that physical fitness is of great importance for both good health, good mood and also cognitive functions. Many researches have been done on its influence on cognitive functions and the conclusion is that physical fitness has a strong impact on it.
Physical exercise is any bodily activity that enhances or maintains physical fitness and overall health and wellness. It is performed for various reasons including strengthening muscles and the cardiovascular system, honing athletic skills, weight loss or maintenance, as well as for the purpose of enjoyment. Frequent and regular physical exercise boosts the immune system, and helps prevent the “diseases of affluence” such as heart disease, cardiovascular disease, Type 2 diabetes and obesity. It also improves mental health, helps prevent depression, helps to promote or maintain positive self esteem, and can even augment an individual’s sex appeal or body image, which is also found to be linked with higher levels of self esteem. Childhood obesity is a growing global concern and physical exercise may help decrease some of the effects of childhood and adult obesity. Health care providers often call exercise the “miracle” or “wonder” drug—alluding to the wide variety of proven benefits that it provides. 
Nearly 200 studies have examined the impact that either acute or long-term exercise has upon cognition. Subsets of these studies have been reviewed using the traditional narrative method, and the common conclusion has been that the results are mixed. Therefore, a more comprehensive review is needed that includes all available studies and that provides a more objective and reproducible review process. Thus, a meta-analytic review was conducted that included all relevant studies with sufficient information for the calculation of effect size ( N = 134). The overall effect size was 0.25, suggesting that exercise has a small positive effect on cognition. Examination of the moderator variables indicated that characteristics related to the exercise paradigm, the participants, the cognitive tests, and the quality of the study influence effect size. However, the most important finding was that as experimental rigor decreased, effect size increased. Therefore, more studies need to be conducted that emphasize experimental rigor. (PsycINFO Database Record (c) 2012 APA, all rights reserved) 
A meta-analytic study was conducted to examine the hypothesis that aerobic fitness training enhances the cognitive vitality of healthy but sedentary older adults. Eighteen intervention studies published between 1966 and 2001 were entered into the analysis. Several theoretically and practically important results were obtained. Most important, fitness training was found to have robust but selective benefits for cognition, with the largest fitness-induced benefits occurring for executive-control processes. The magnitude of fitness effects on cognition was also moderated by a number of programmatic and methodological factors, including the length of the fitness-training intervention, the type of the intervention, the duration of training sessions, and the gender of the study participants. The results are discussed in terms of recent neuroscientific and psychological data that indicate cognitive and neural plasticity is maintained throughout the life span. 
To determine by meta-analysis whether physical exercises are beneficial for people with dementia and related cognitive impairments.
Reviewed studies were limited to randomized trials evaluating exercise in persons 65 years of age or older with cognitive impairment. Studies included quantitative results (means, standard deviations, t tests, F tests) for physical fitness, physical functioning, cognition, or behavior outcomes.
A total of 2020 subjects participated in the 30 trials that met the inclusion criteria. Summary effects were computed using a fixed effects (Hedge’s gi) model. Significant summary effect sizes (ES) were found for strength (ES=.75; 95% confidence interval [CI], .58–.92), physical fitness (ES=.69; 95% CI, .58–.80), functional performance (ES=.59; 95% CI, .43–.76), cognitive performance (ES=.57; 95% CI, 0.43–1.17), and behavior (ES=.54; 95% CI, .36–.72). The overall mean ES between exercise and nonexercise groups for all outcomes was .62 (95% CI, .55–.70).
Exercise training increases fitness, physical function, cognitive function, and positive behavior in people with dementia and related cognitive impairments. 
Reviews theory and research that have attempted to relate fitness training to improvements on psychological variables among normals as well as selected clinical populations. Theoretical speculations in this area are critiqued, and research designs are evaluated as either experimental or quasi-experimental and therefore interpretable, or preexperimental and therefore largely uninterpretable. The research suggests that physical fitness training leads to improved mood, self-concept, and work behavior; the evidence is less clear as to its effects on cognitive functioning, although it does appear to bolster cognitive performance during and after physical stress. Except for self-concept, personality traits are not affected by improvements in physical fitness. Mentally retarded children demonstrate psychological improvement following physical fitness training, but no conclusion can be reached regarding the effects of physical fitness training with other clinical syndromes. (2½ p ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved) 
The effect of physical exercise on mental function has been widely studied from the beginning of the 20th century. However, the contradictory findings of experimental research have led authors to identify several methodological factors to control in such studies including: (i) the nature of the psychological task; and (ii) the intensity and duration of physical exercise. The purpose of this article is to provide information, from the perspective of performance optimisation, on the main effects of physical task characteristics on cognitive performance. Within this framework, some consistent results have been observed during the last decade. Recent studies, using mainly complex decisional tasks, have provided the research community with clear support for an improvement of cognitive performance during exercise. Diverse contributing factors have been suggested to enhance cognitive efficacy. First, an increase in arousal level related to physical exertion has been hypothesised. Improvement in decisional performance has been observed immediately after the adrenaline threshold during incremental exercise. Such positive effects could be enhanced by nutritional factors, such as carbohydrate or fluid ingestion, but did not seem to be influenced by the level of fitness. Second, the mediating role of resource allocation has been suggested to explain improvement in cognitive performance during exercise. This effect highlights the importance of motivational factors in such tasks. Finally, when the cognitive performance was performed during exercise, consistent results have indicated that the dual task effect was strongly related to energetic constraints of the task. The greater the energy demand, the more attention is used to control movements. 
Regular exercise has a great beneficial influence on cognitive functioning and overall health. A person needs to be persistant and exercise contiously and cognitive function will improve one way or the other.
 ”The influence of physical fitness and exercise upon cognitive functioning: A meta-analysis.” by: Etnier, Jennifer L.; Salazar, Walter; Landers, Daniel M.; Petruzzello, Steven J.; Han, Myungwoo; Nowell, Priscilla
 ”Fitness Effects on the Cognitive Function of Older Adults, A Meta-Analytic Study” by: Stanley Colcombe and, Arthur F. Kramer
 ”The effects of exercise training on elderly persons with cognitive impairment and dementia: A meta-analysis1” by: Patricia Heyn, PhD, Beatriz C. Abreu, PhD, OTR, Kenneth J. Ottenbacher, PhD
 ”Physical fitness training and mental health.” by: Folkins, Carlyle H.; Sime, Wesley E.
 ”Effects of Acute Physical Exercise Characteristics on Cognitive Performance” by: Brisswalter J.; Collardeau M.; René A.