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Prostate cancer affects a major proportion of older men, and effective preventive measures are few. Earlier suggestions of 10-30% risk reduction from vigorous physical activity thus merit further analysis. This narrative review updates information on associations between physical activity and prostate cancer, seeking activity patterns associated with maximal risk reduction. Systematic searches of Ovid/MEDLINE and PubMed databases from 1996 to June 2016 have linked the terms prostate neoplasms/prostate cancer with occupation, occupational title, sedentary job or heavy work, exercise, physical activity, sports, athletes, physical education/training or aerobic fitness. Combining these searches with findings from earlier reviews, 85 analyses were captured, although three were repeat analyses of the same data set. Seven analyses reported increased risk, and a further 31 showed no clear relationship. However, 24 analyses found a trend to diminished risk, and 21 a significant decrease (10-30% or more) in at least some subject subsets. Benefit was seen more consistently in occupational than in leisure studies, usually with adolescence or the early 20 s as the optimal age for preventive activity. In general, benefit showed a dose-response relationship, with vigorous activity required for maximal effect. Furthermore, several recent observational studies have indicated that physical activity is beneficial in preventing disease recurrence and improving survival following the diagnosis and treatment of prostate cancer. Despite continued research, conclusive proof of an association between regular physical activity and a low risk of prostate cancer remains elusive. However, reports that exercise exacerbates risk are few, and despite issues around controls, covariates, and co-morbidities, an impressive number of studies have now found significant benefit, suggesting that regular physical activity is important in terms of disease development, progression, and therapy. Given also the many other health benefits of an active lifestyle, it can be recommended as a potentially useful measure in the prevention of prostate cancer.

Relationships between peptic ulcer and physical activity have as yet received little attention. The prevalence of ulceration is high in racehorses and sled dogs, particularly during periods of competition. In humans, some occupational comparisons show an increased risk among manual workers, but it remains difficult to separate effects of work-related activity from social class and attendant influences of smoking, excessive alcohol consumption, shift work, and other stressors. Two studies of leisure activity point to some benefit from moderate physical activity, one finding a reduced risk of gastric ulcers and the other finding no effect on gastric ulcers but a reduced risk of duodenal ulcers in men only. Moderate physical activity could have a favorable impact on a number of risk factors for peptic ulceration. It could reduce gastric secretions and enhance immune function, with the latter reducing the risk of Helicobacter pylori infection. Moderate activity might also reduce anxiety and encourage the adoption of a healthy lifestyle, with avoidance of smoking and an excessive consumption of alcohol. However, prolonged endurance exercise seems likely to have a negative impact, suppressing immune function, reducing mucosal blood flow, and calling for frequent administration of non-steroidal anti-inflammatory drugs (NSAIDs). As with other aspects of exercise medicine, there may be a J-shaped relationship between dose and response. Limited human observations suggest a favourable response to bouts of moderate leisure activity but little benefit from heavy occupational activity and, in some animal studies, negative effects at high volumes and intensities of exercise. Further research is recommended to confirm the nature of this relationship, clarify the location of any nadir of risk for various classes of individual, and to explore mechanisms and antidotes.

Cholecystitis and gallstones affect a large segment of the population in developed nations, and a small proportion of affected individuals subsequently develop cancer of the gallbladder. However, little is known about the possible beneficial effects of physical activity. Accordingly, a systematic review examined the influence of both acute and chronic exercise on gallbladder motility, and relationships were examined between habitual physical activity, gallbladder disease, and gallbladder cancer. A search of Ovid/MEDLINE from 1996 to November 2014 yielded 67 articles relating to physical activity and gallbladder function or disease; 18 of these relevant to the objectives of the review were supplemented by 22 papers from personal files and other sources. Because of the limited volume of material, all were considered, although note was taken of the quality of activity measurement, care in excluding covariates, and experimental design (cross-sectional, case-control or randomized controlled trial). The impact of physical activity upon gallbladder function remains unclear; acute activity could augment emptying by stimulating cholecystokinin release, and one of two training experiments found a small increase in gallbladder motility. The largest and most recent cross-sectional and case-control trials show a reduced risk of gallbladder disease in active individuals. A small number of randomized controlled trials in humans and one animal study generally support these trends, although the number of cases of gallstones are too few for statistical significance. Three studies of gallbladder cancer also show a non-significant trend to benefit from physical activity. Although there remains a need for further research, regular physical activity seems likely to reduce the risk of both gallstones and gallbladder cancer. A substantial number of individuals must be persuaded to exercise in order to avoid one case of gallbladder disease, but the attempt appears warranted because of the other health benefits of regular physical activity.

European and North American cardiologists have long debated the need for mandatory ECG screening of athletes in order to prevent sudden cardiac death. European investigators have recently adduced new evidence, which they believe supports the need for such screening. They note a decrease of sudden cardiac deaths among Italian athletes following the introduction of mandatory screening in that country, clearer definitions of resting ECG abnormalities in athletes, new and more encouraging calculations of cost/ benefit ratios and direct comparisons of clinical examination alone against clinical examination plus ECG screening. Nevertheless, it seems that critical criteria for the success of any screening procedure (a substantial prevalence of the problem, coupled with an adequate test sensitivity and specificity) have yet to be satisfied. Very few athletes are liable to sudden cardiac death, only a few of those who are vulnerable will be identified by ECG screening, and even if all potential cases could be detected, restriction of their physical activity would be unlikely to have a major influence on their prognosis. At the same time, a requirement of mandatory testing would discourage engagement in physical activity, and would impose substantial direct costs on the community. Moreover, the large number of false positive test results could have important and undesirable consequences for both indirect medical costs and the overall health of competitors. ECG screening might become more effective if it could be focused on a smaller sub-group of vulnerable athletes, or if the problem of false positive tests could be addressed through an increase of test specificity. However, on the basis of current information, it would seem better to direct efforts in preventive medicine to more common causes of premature death in the young adult.

Over the past 13 years, Noakes and his colleagues have argued repeatedly for the existence of a 'Central Governor', a specific brain centre that provides a feed-forward regulation of the intensity of vigorous effort in order to conserve homeostasis, protecting vital organs such as the brain, heart and skeletal muscle against damage from hyperthermia, ischaemia and other manifestations of catastrophic failure. This brief article reviews evidence concerning important corollaries of the hypothesis, examining the extent of evolutionary pressures for the development of such a mechanism, the effectiveness of protection against hyperthermia and ischaemia during exhausting exercise, the absence of peripheral factors limiting peak performance (particularly a plateauing of cardiac output and oxygen consumption) and proof that electromyographic activity is limiting exhausting effort. As yet, there is a lack of convincing experimental evidence to support these corollaries of the hypothesis; furthermore, some findings, such as the rather consistent demonstration of an oxygen consumption plateau in young adults, argue strongly against the limiting role of a 'Central Governor'.

In older adults, as in younger individuals, habitual moderate-intensity physical activity is associated with a reduced risk of various chronic health conditions, including certain types of cardiovascular and musculoskeletal disease and certain forms of cancer. However, the pattern of physical activity associated with such benefits remains unclear. One problem is that most investigators have examined patterns of physical activity using either subjective questionnaires or accelerometer or pedometer measurements limited to a single week, despite clear evidence of both the unreliability/invalidity of questionnaires and seasonal changes in activity patterns. Since 2000, we have thus conducted an interdisciplinary study examining the habitual physical activity and health of elderly people living in a medium-sized Japanese town (the Nakanojo Study). In about one-tenth of some 5000 available subjects agedor =65 years, physical activity has already been assessed continuously for 24 h/day for8 years using a specially adapted pedometer/accelerometer. This device has a storage capacity of 36 days and can distinguish10 intensities of physical activity (expressed in metabolic equivalents [METs]). Data have to date been summarized as daily step counts and daily durations of activity of3 and3 METs, averaged over a 1-year period. This article provides a detailed overview of both factors influencing habitual physical activity and relationships between such activity and health in an elderly population. To date, analyses have been cross-sectional in type. Substantial associations have been noted between the overall health of participants and both the daily duration of effort undertaken at an intensity of3 METs and the daily step count. In men, the extent of health is associated more closely with the daily duration of activity of3 METs than with the daily step count, whereas in women, the association is closer for the step count than for the duration of activity3 METs. In both sexes, the threshold amount of physical activity associated with better health is greater for physical than for mental benefits:8000 versus4000 steps/day and/or20 versus5 min/day at an intensity3 METs, respectively. In other words, better physical health is seen in those spending at least 20 min/day in moderate walking (at a pace of around 1.4 m/s [5 km/h]) and a further60 min of light activity per day. In contrast, better mental health is associated with much smaller amounts of deliberate physical activity. The daily step count and the daily durations of activity of3 and3 METs are all influenced by meteorological factors, particularly precipitation and mean ambient temperature. Activity decreases exponentially to about 4000 steps/day as precipitation increases. Excluding the influence of rainfall, the daily step count peaks at a mean outdoor temperature of around 17 degrees C; above and especially below such readings, physical activity decreases as a quadratic function of temperature. Seasonal changes in microclimate should thus be considered when designing interventions intended to increase the habitual physical activity of elderly people. The observed associations between physical activity and health outcomes point to a need for longitudinal analyses; these should examine potential causal interpretations of the current findings and elucidate possible additional mediating variables.

This article documents current literature on the potential long-term effects of school physical education on various outcomes in adults. A first observation is the rarity of publications on this topic. Nevertheless, the available literature suggests that physical education should offer a variety of either lifelong physical activities or sports in order to reach children with differing interests. In some children, competitive sports may generate a lifelong interest in physical activity, but most children may be better socialized by lifelong physical activities. In order to expose children to such a wide choice of physical activities, more time should be allocated to physical education instruction. Substantial further research is needed to increase our understanding of the long-term impact of school physical education programmes.

Although children and youth currently form the most active segments of the population in developed societies, there is a marked trend toward an increase in sedentary lifestyle among school-age children. The purpose of this review is to analyse the effects of school physical education (PE) programmes on: (i) the physical activity (PA) levels of participants as children and adults; and (ii) attitudes toward PE and PA in the same groups. Based on the literature analysed, it can be suggested that a sufficient quantity of a quality PE programme can contribute significantly to the overall amount of moderate-to-intense PA of the school-age child. Schools also have the potential to influence the habitual PA of children by encouraging increased participation in extracurricular sports activities, by favouring active commuting to school and by providing exercise equipment and supervision for youth in their neighbourhoods. Most young children have a very positive attitude towards PE. However, as they grow older, their perception of PE as a positive experience seems to become more ambiguous. From the few studies available, it seems likely that quality PE programmes help to maintain initial positive perceptions. Future research should address factors influencing the change of perceptions as a child matures. In addition to offering a quality PE programme, schools should ensure that the total weekly amount of PE is sufficient not only to maintain but also to enhance a child's physical fitness. More research is needed to determine the ability of school PE programmes to influence PA behaviour in adult life and to evaluate strategies that will make optimal use of the curricular time allocated to PE.

Regression to the mean (RTM) can bias any investigation where the response to treatment is classified relative to initial values for a given variable without the use of an appropriate control group. The phenomenon and resulting errors of interpretation have been recognised by clinicians in a number of disciplines. The causes of RTM include both intra-individual variance and measurement error. The magnitude of RTM can be estimated quite simply, given a knowledge of intra- and inter-individual variance. RTM can be avoided by using a fully controlled experimental design. Difficulties can also be minimised by making duplicate measurements prior to the experimental manipulation, the first measurement serving for classification, and the second (with randomly distributed variance) allowing an assessment of the response to treatment. Less satisfactorily, surrogate measurements (for example, plasma volume for maximal oxygen intake [VO2(max)]) can assess the bias introduced by an initial non-random sorting of study participants. The impact of RTM on the design and interpretation of investigations has as yet received little consideration by exercise scientists and sports physicians. The response to training is often related to initial measurements of a dependent variable such as heart size, ST segmental depression, fitness or level of physical activity. In particular, analyses of this type have been adduced to support the belief that the response to aerobic training is inversely related to an individual's VO2(max). In fact, RTM may account for a major part of this apparent relationship.

The circulating blood normally contains no more than 1-2% of the body's population of leucocytes. The numbers and phenotypes of circulating leucocyte subsets can change dramatically during and immediately following exercise. The surface expression of adhesion molecules makes an important contribution to such responses by changing patterns of cell trafficking. Alterations in the surface expression of adhesion molecules could reflect a shedding of molecules, selective apoptosis or differential trafficking of cells with a particular phenotype, effects from mechanical deformation of the cytoplasm, active biochemical processes involving cytokines, catecholamines, glucocorticoids or other hormones, or changes in the induction of adhesion molecules. The expression of adhesion molecules changes with maturation and activation of leucocytes. Typically, mature cells express lower densities of L-selectin (CD62L), the homing receptor for secondary lymphoid organs, and higher densities of LFA-1 (CD11a), the molecule associated with trafficking to non-lymphoid reservoir sites. The neutrophils and natural killer cells that are mobilised during exercise also express high levels of Mac-1 (CD11b), a marker associated with cellular activation. Possibly, exercise demarginates older cells that are awaiting destruction in the spleen. Plasma concentrations of catecholamines rise dramatically with exercise, and there is growing evidence that catecholamines, acting through a cyclic adenosine monophosphate second messenger system, play an important role in modifying the surface expression of adhesion molecules. Analogous changes can be induced by other forms of stress that release catecholamines or by catecholamine infusion, and responses are blocked by beta(2)-blocking agents. Catecholamines also modify adherence and expression of adhesion molecules in vitro. Cell trafficking is modified by genetic deficiencies in the expression of adhesion molecules, but leucocyte responses to exercise and catecholamines are generally unaffected by splenectomy. A number of clinical conditions including atherogenesis and metaplasia are marked by an altered expression of adhesion molecules. The effects of exercise on these molecules could thus have important health implications.

Ethical evaluation is a vital but sometimes neglected component of research policy in the exercise sciences. This article reviews some issues in human research, with particular reference to studies undertaken by the exercise scientist. The typical composition and functions of the research review committee are examined in the context of individual and institutional ethical norms. In multicentre trials, there are often problems in coordinating ethical approval between institutions. On-going monitoring of research may have value in the detection of fraud. A reduction in the secrecy of committee proceedings would allow a closer auditing of the research review process. Authors need to give more thought to developing appropriate research questions. Scarce resources may be wasted because of inappropriate study design or an inadequate statistical analysis of the results. The costs of any proposed investigation must be weighed carefully against possible benefits. Confidentiality is particularly important when collecting data at the worksite or over the internet. Informed consent should be based on a full disclosure of risks; the participant should be competent to understand the nature and magnitude of these risks, and undue pressure to participate in an experiment must be avoided. The opposition to placebo trials expressed in the Declaration of Helsinki requires careful consideration of the use of control groups, since regular exercise is known to benefit health. If research is conducted in under-developed societies, the standards of treatment of the participants should match those expected in developed societies. The publication of findings must be fair and well balanced; examples of fraud and misconduct continue to be reported. Some journals apparently still publish papers, even if they have not received an initial institutional review. Editors should restore meaning to the word 'author', avoid the bias to a publication of 'positive' results, limit the impact of commercial sponsorship on reporting and curtail the current trend to redundant presentations and publications. Development of academic courses in research ethics may help to avoid some of these abuses.

Cytokines are soluble glycoproteins that are produced by and mediate communication between and within immune and nonimmune cells, organs and organ systems throughout the body. Pro- and anti-inflammatory mediators constitute the inflammatory cytokines, which are modulated by various stimuli, including physical activity, trauma and infection. Physical activity affects local and systemic cytokine production at different levels, often exhibiting striking similarity to the cytokine response to trauma and infection. The present review examines the cytokine response to short term exercise stress, with an emphasis on the balance between pro- and anti-inflammatory mechanisms and modulation of both innate and specific immune parameters through cytokine regulation. The effects of long term exercise on cytokine responses and the possible impact on various facets of the immune system are also discussed, with reference to both cross-sectional and longitudinal studies of exercise training. Finally, the validity of using exercise as a model for trauma and sepsis is scruti- nised in the light of physiological changes, symptomatology and outcome, and limitations of the model are addressed. Further studies, examining the effect of exercise, trauma and infection on novel cytokines and cytokine systems are needed to elucidate the significance of cytokine regulation by physical activity and, more importantly, to clarify the health implications of short and long term physical activity with respect to overall immune function and resistance to infection.

The chronic fatigue syndrome is characterised by a fatigue that is disproportionate to the intensity of effort that is undertaken, has persisted for 6 months or longer, and has no obvious cause. Unless there has been a long period of patient- or physician- imposed inactivity, objective data may show little reduction in muscle strength or peak aerobic power, but the affected individual avoids heavy activity. The study of aetiology and treatment has been hampered by the low disease prevalence (probably