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Stroke Jul 2015
Review
Topics: Animals; Cognition; Cognition Disorders; Exercise; Humans; Resistance Training; Stroke
PubMed: 26012638
DOI: 10.1161/STROKEAHA.114.006649 -
The Cochrane Database of Systematic... Apr 2015There is increasing evidence that physical activity supports healthy ageing. Exercise is helpful for cardiovascular, respiratory and musculoskeletal systems, among... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
There is increasing evidence that physical activity supports healthy ageing. Exercise is helpful for cardiovascular, respiratory and musculoskeletal systems, among others. Aerobic activity, in particular, improves cardiovascular fitness and, based on recently reported findings, may also have beneficial effects on cognition among older people.
OBJECTIVES
To assess the effect of aerobic physical activity, aimed at improving cardiorespiratory fitness, on cognitive function in older people without known cognitive impairment.
SEARCH METHODS
We searched ALOIS - the Cochrane Dementia and Cognitive Improvement Group's Specialized Register, the Cochrane Controlled Trials Register (CENTRAL) (all years to Issue 2 of 4, 2013), MEDLINE (Ovid SP 1946 to August 2013), EMBASE (Ovid SP 1974 to August 2013), PEDro, SPORTDiscus, Web of Science, PsycINFO (Ovid SP 1806 to August 2013), CINAHL (all dates to August 2013), LILACS (all dates to August 2013), World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (http://apps.who.int/trialsearch), ClinicalTrials.gov (https://clinicaltrials.gov) and Dissertation Abstracts International (DAI) up to 24 August 2013, with no language restrictions.
SELECTION CRITERIA
We included all published randomised controlled trials (RCTs) comparing the effect on cognitive function of aerobic physical activity programmes with any other active intervention, or no intervention, in cognitively healthy participants aged over 55 years.
DATA COLLECTION AND ANALYSIS
Two review authors independently extracted the data from included trials. We grouped cognitive outcome measures into eleven categories covering attention, memory, perception, executive functions, cognitive inhibition, cognitive speed and motor function. We used the mean difference (or standardised mean difference) between groups as the measure of the treatment effect and synthesised data using a random-effects model. We conducted separate analyses to compare aerobic exercise interventions with no intervention and with other exercise, social or cognitive interventions. Also, we performed analyses including only trials in which an increase in the cardiovascular fitness of participants had been demonstrated.
MAIN RESULTS
Twelve trials including 754 participants met our inclusion criteria. Trials were from eight to 26 weeks in duration.We judged all trials to be at moderate or high risk of bias in at least some domains. Reporting of some risk of bias domains was poor.Our analyses comparing aerobic exercise to any active intervention showed no evidence of benefit from aerobic exercise in any cognitive domain. This was also true of our analyses comparing aerobic exercise to no intervention. Analysing only the subgroup of trials in which cardiorespiratory fitness improved in the aerobic exercise group showed that this improvement did not coincide with improvements in any cognitive domains assessed. Our subgroup analyses of aerobic exercise versus flexibility or balance interventions also showed no benefit of aerobic exercise in any cognitive domain.Dropout rates did not differ between aerobic exercise and control groups. No trial reported on adverse effects.Overall none of our analyses showed a cognitive benefit from aerobic exercise even when the intervention was shown to lead to improved cardiorespiratory fitness.
AUTHORS' CONCLUSIONS
We found no evidence in the available data from RCTs that aerobic physical activities, including those which successfully improve cardiorespiratory fitness, have any cognitive benefit in cognitively healthy older adults. Larger studies examining possible moderators are needed to confirm whether or not aerobic training improves cognition.
Topics: Aged; Cognition; Cognition Disorders; Exercise; Humans; Memory; Middle Aged; Oxygen Consumption; Physical Fitness; Randomized Controlled Trials as Topic
PubMed: 25900537
DOI: 10.1002/14651858.CD005381.pub4 -
NeuroImage Feb 2018Hippocampal volume increase in response to aerobic exercise has been consistently observed in animal models. However, the evidence from human studies is equivocal. We... (Meta-Analysis)
Meta-Analysis Review
Hippocampal volume increase in response to aerobic exercise has been consistently observed in animal models. However, the evidence from human studies is equivocal. We undertook a systematic review to identify all controlled trials examining the effect of aerobic exercise on the hippocampal volumes in humans, and applied meta-analytic techniques to determine if aerobic exercise resulted in volumetric increases. We also sought to establish how volume changes differed in relation to unilateral measures of left/right hippocampal volume, and across the lifespan. A systematic search identified 4398 articles, of which 14 were eligible for inclusion in the primary analysis. A random-effects meta-analysis showed no significant effect of aerobic exercise on total hippocampal volume across the 737 participants. However, aerobic exercise had significant positive effects on left hippocampal volume in comparison to control conditions. Post-hoc analyses indicated effects were driven through exercise preventing the volumetric decreases which occur over time. These results provide meta-analytic evidence for exercise-induced volumetric retention in the left hippocampus. Aerobic exercise interventions may be useful for preventing age-related hippocampal deterioration and maintaining neuronal health.
Topics: Exercise; Hippocampus; Humans
PubMed: 29113943
DOI: 10.1016/j.neuroimage.2017.11.007 -
Sports Medicine (Auckland, N.Z.) Jan 2017Exercise and the subsequent recovery processes have been proposed to induce disturbances in zinc homeostasis. We previously reported acute increase in serum zinc... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Exercise and the subsequent recovery processes have been proposed to induce disturbances in zinc homeostasis. We previously reported acute increase in serum zinc concentration immediately after aerobic exercise; the change in the indices of zinc status during exercise recovery was not explored.
OBJECTIVE
The aim of the current analysis is to determine the changes in zinc biomarkers during recovery from an aerobic exercise bout.
METHODS
We conducted a systematic literature search on PubMed, Web of Science, Scopus and SPORTDiscus electronic databases from inception to 20 December 2014 to identify studies that investigated the acute effects of exercise on selected indices of zinc status. Meta-analyses were conducted to determine the change in serum zinc concentration during exercise recovery, defined as up to 4 h following exercise cessation, compared to pre-exercise levels.
RESULTS
Forty-five studies were included in the systematic literature review, of which 12 studies (providing 18 comparisons) reported serum zinc levels after the cessation of exercise. During exercise recovery, serum zinc concentration was significantly lower than pre-exercise values (-1.31 ± 0.22 μmol/L, P < 0.001; mean ± SE). Secondary analyses showed a significant decrease of serum zinc levels in all categories of participants' training status, mode of exercise and time of blood collection. Insufficient data were available for meta-analysis of other zinc biomarkers.
CONCLUSIONS
The present analysis showed that serum zinc levels decrease significantly during exercise recovery, compared to pre-exercise levels. This extends our previous report of an increase in serum zinc immediately after exercise. We postulate that the exercise-induced fluctuations in zinc homeostasis are linked to the muscle repair mechanisms following exercise; the potential for zinc to enhance the exercise recovery process remains to be determined.
Topics: Exercise; Homeostasis; Humans; Zinc
PubMed: 27260681
DOI: 10.1007/s40279-016-0567-0 -
The Cochrane Database of Systematic... Jul 2006Physiological responses of the fetus (especially increase in heart rate) to single, brief bouts of maternal exercise have been documented frequently. Many pregnant women... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Physiological responses of the fetus (especially increase in heart rate) to single, brief bouts of maternal exercise have been documented frequently. Many pregnant women wish to engage in aerobic exercise during pregnancy but are concerned about possible adverse effects on the outcome of pregnancy.
OBJECTIVES
The objective of this review was to assess the effects of advising healthy pregnant women to engage in regular aerobic exercise (at least two to three times per week), or to increase or reduce the intensity, duration, or frequency of such exercise, on physical fitness, the course of labour and delivery, and the outcome of pregnancy.
SEARCH STRATEGY
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (June 2005), MEDLINE (1966 to 2005 January Week 1), EMBASE (1980 to 2005 January Week 1), Conference Papers Index (earliest to 2005 January Week 1), contacted researchers in the field and searched reference lists of retrieved articles.
SELECTION CRITERIA
Acceptably controlled trials of prescribed exercise programs in healthy pregnant women.
DATA COLLECTION AND ANALYSIS
Both review authors independently assessed trial quality and extracted data. Study authors were contacted for additional information.
MAIN RESULTS
Eleven trials involving 472 women were included. The trials were small and not of high methodologic quality. Five trials reported significant improvement in physical fitness in the exercise group, although inconsistencies in summary statistics and measures used to assess fitness prevented quantitative pooling of results. Seven trials reported on pregnancy outcomes. A pooled increased risk of preterm birth (relative risk 1.82, 95% confidence interval (CI) 0.35 to 9.57) with exercise, albeit statistically nonsignificant, does not cohere with the absence of effect on mean gestational age (weighted mean difference +0.3, 95% CI -0.2 to +0.9 weeks), while the results bearing on growth of the fetus are inconsistent. One small trial reported that physically fit women who increased the duration of exercise bouts in early pregnancy and then reduced that duration in later pregnancy gave birth to larger infants with larger placentas.
AUTHORS' CONCLUSIONS
Regular aerobic exercise during pregnancy appears to improve (or maintain) physical fitness. Available data are insufficient to infer important risks or benefits for the mother or infant. Larger and better trials are needed before confident recommendations can be made about the benefits and risk of aerobic exercise in pregnancy.
Topics: Exercise; Female; Humans; Physical Fitness; Pregnancy; Pregnancy Outcome; Randomized Controlled Trials as Topic
PubMed: 16855953
DOI: 10.1002/14651858.CD000180.pub2 -
Neuroscience and Biobehavioral Reviews Sep 2021An increasing number of studies has focused on the after-effects of acute aerobic exercise on executive function. To date, empirical evidence lacks consensus regarding... (Meta-Analysis)
Meta-Analysis Review
An increasing number of studies has focused on the after-effects of acute aerobic exercise on executive function. To date, empirical evidence lacks consensus regarding whether acute aerobic exercise has beneficial effects on executive function. To identify possible sources of this discrepancy, the present study focused on executive function demands and pre-test cognitive performance, and performed the first meta-analysis of individual participant data (IPD meta-analysis) in this area of research. Results indicated that the beneficial after-effects of acute aerobic exercise on cognitive performance were greater in participants with lower cognitive performance at pre-test. Acute aerobic exercise offered general benefits to cognitive performance irrespective of executive function demands, when pre-test cognitive performance was appropriately controlled. Thus, the present IPD meta-analysis suggests that pre-test cognitive performance is one possible source of the conflicting findings in acute exercise studies. Future research is encouraged to consider pre-test cognitive performance to avoid underestimating the beneficial after-effects of acute exercise.
Topics: Cognition; Executive Function; Exercise; Humans
PubMed: 34147558
DOI: 10.1016/j.neubiorev.2021.06.026 -
Dialogues in Clinical Neuroscience Sep 2019Cognitive symptoms are a core feature of schizophrenia and are related to an unfavorable disease outcome. So far, there are no satisfactory pharmacological approaches to... (Meta-Analysis)
Meta-Analysis Review
Cognitive symptoms are a core feature of schizophrenia and are related to an unfavorable disease outcome. So far, there are no satisfactory pharmacological approaches to address cognitive symptoms. For some time now, aerobic exercise has been demonstrated in various trials to be a promising candidate for this indication. The aim of this brief qualitative review was to present the most recent meta-analyses regarding the capacity of exercise to improve cognition in schizophrenia patients. Additionally, we give a short overview of the effects in other conditions, like healthy subjects and patients with major depression. We conducted a focused literature search using the PubMed database, concentrating on meta-analyses which are based on a systematic search. The most recent meta-analysis investigating the efficacy of aerobic exercise on cognitive impairments in schizophrenia patients provides evidence that exercise has positive effects on cognitive functioning in this population. However, the effect seems not to be specific; there were positive findings regarding healthy subjects and patients with depressive disorders as well, even if they were less consistent. As most available trials have a small to modest sample size and have no consensus with regard to the intervention regime, nor to the assessment of cognition, the findings are difficult to generalize. In the future, standardized clinical trials focusing on the long-term effects of exercise are needed to evaluate whether the improvements in cognition are sustainable. .
Topics: Clinical Trials as Topic; Cognitive Dysfunction; Exercise; Humans; Schizophrenia; Schizophrenic Psychology; Treatment Outcome
PubMed: 31749650
DOI: 10.31887/DCNS.2019.21.3/aschmitt -
Oxidative Medicine and Cellular... 2018High altitude training is one of the effective strategies for improving aerobic exercise performance at sea level via altitude acclimatization, thereby improving oxygen... (Review)
Review
High altitude training is one of the effective strategies for improving aerobic exercise performance at sea level via altitude acclimatization, thereby improving oxygen transport and/or utilization. But its underlying molecular mechanisms on physiological functions and exercise performance of athletes are still vague. More recent evidence suggests that the recycling of cellular components by autophagy is an important process of the body involved in the adaptive responses to exercise. Whether high altitude training can activate autophagy or whether high altitude training can improve exercise performance through exercise-induced autophagy is still unclear. In this narrative review article, we will summarize current research advances in the improvement of exercise performance through high altitude training and its reasonable molecular mechanisms associated with autophagy, which will provide a new field to explore the molecular mechanisms of adaptive response to high altitude training.
Topics: Acclimatization; Altitude; Autophagy; Exercise; Humans
PubMed: 29849885
DOI: 10.1155/2018/3617508 -
The International Journal of... Jul 2017Physical activity may play a role in both the prevention and slowing of brain volume loss and may be beneficial in terms of improving the functional connectivity of... (Review)
Review
Physical activity may play a role in both the prevention and slowing of brain volume loss and may be beneficial in terms of improving the functional connectivity of brain regions. But much less is known about the potential benefit of aerobic exercise for the structure and function of the default mode network (DMN) brain regions. This systematic review examines the effects of aerobic exercise on the structure and function of DMN brain regions in human adulthood. Seven electronic databases were searched for prospective controlled studies published up to April 2015. The quality of the selected studies was evaluated with the Cochrane Collaboration's tool for assessing the risk of bias. RevMan 5.3 software was applied for data analysis. Finally, 14 studies with 631 participants were identified. Meta-analysis revealed that aerobic exercise could significantly increase right hippocampal volume (SMD = 0.26, 95% CI 0.01-0.51, p = 0.04, I = 7%, 4 studies), and trends of similar effects were observed in the total (SMD = 0.12, 95% CI -0.17 to 0.41, p = 0.43, I = 0%, 5 studies), left (SMD = 0.12, 95% CI -0.13 to 0.37, p = 0.33, I = 14%, 4 studies), left anterior (SMD = 0.12, 95% CI -0.16 to 0.40, p = 0.41, I = 74%, 2 studies) and right anterior (SMD = 0.10, 95% CI -0.17 to 0.38, p = 0.46, I = 76%, 4 studies) hippocampal volumes compared to the no-exercise interventions. A few studies reported that relative to no-exercise interventions, aerobic exercise could significantly decrease the atrophy of the medial temporal lobe, slow the anterior cingulate cortex (ACC) volume loss, increase functional connectivity within the hippocampus and improve signal activation in the cingulate gyrus and ACC. The current review suggests that aerobic exercise may have positive effects on the right hippocampus and potentially beneficial effects on the overall and other parts of the hippocampus, the cingulate cortex and the medial temporal areas of the DMN. Moreover, aerobic exercise may increase functional connectivity or activation in the hippocampus, cingulate cortex and parahippocampal gyrus regions of the DMN. However, considering the quantity and limitations of the included studies, the conclusion could not be drawn so far. Additional randomized controlled trials (RCTs) with rigorous designs and longer intervention periods are needed in the future.
Topics: Brain; Brain Diseases; Exercise; Exercise Therapy; Humans; Nerve Net
PubMed: 27412353
DOI: 10.1080/00207454.2016.1212855 -
Canadian Journal of Applied Physiology... Jun 1993The endocrine effects of pregnancy cause striking changes in maternal metabolism, cardiovascular regulation, acid-base balance, and thermoregulation at rest and during... (Review)
Review
The endocrine effects of pregnancy cause striking changes in maternal metabolism, cardiovascular regulation, acid-base balance, and thermoregulation at rest and during standard submaximal exercise. The apparent purpose of these changes is to accommodate fetal needs in addition to those of the exercising woman. A significant body of evidence supports the hypothesis that healthy women can perform acute exercise of moderate intensity and duration without jeopardizing fetal well-being. Compiled studies also suggest that maximal oxygen uptake (VO2max, L.min-1) and the work rate at the onset of blood lactate accumulation (OBLA) are not significantly altered during the course of a normal pregnancy. However, some evidence suggests that maximal anaerobic power may be reduced. More information is needed on maternal cardiorespiratory function, carbohydrate metabolism, and acid-base balance at exercise intensities above OBLA and on fetal adaptability to strenuous maternal exercise. Recent studies support the view that moderate fitness conditioning can augment maternal metabolic and cardiopulmonary capacities without altering fetal development or pregnancy outcome. Implications of recent scientific studies for the design of aerobic exercise programs for pregnant women are discussed.
Topics: Exercise; Female; Fetus; Humans; Pregnancy
PubMed: 8513287
DOI: 10.1139/h93-011