Effect of exercise on in vitro immune function: a 12-month randomized, controlled trial among postmenopausal women

Impact of exercise on markers of B cell-related immunity: A systematic review

BACKGROUND

B cells represent a crucial component of adaptive immunity that ensures long-term protection from infection by generating pathogen-specific immunoglobulins. Exercise alters B cell counts and immunoglobulin levels, but evidence-based conclusions on potential benefits for adaptive immunity are lacking. This systematic review assessed current literatures on the impact of acute exercise and exercise training on B cells, immunoglobulins, and markers of secretory immunity in human biofluids.

METHODS

According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, MEDLINE, Web of Science, and Embase were searched on March 8, 2023. Non-randomized controlled trials and crossover trials investigating the impact of acute exercise or exercise training on B cell counts and proportions, immunoglobulin levels, salivary flow rate, or secretory immunoglobulin A secretion rate were included. Quality and reporting of exercise training studies were assessed using the Tool for the Assessment of Study Quality and reporting in Exercise. Study characteristics, outcome measures, and statistically significant changes were summarized tabularly.

RESULTS

Of the 67 eligible studies, 22 applied acute exercise and 45 applied exercise training. All included outcomes revealed significant alterations over time in acute exercise and exercise training context, but only a few investigations showed significant differences compared to control conditions. Secretory and plasma immunoglobulin A levels were most consistently increased in response to exercise training.

CONCLUSION

B cell-related outcomes are altered by acute exercise and exercise training, but evidence-based conclusions cannot be drawn with high confidence due to the large heterogeneity in populations and exercise modalities. Well-designed trials with large sample sizes are needed to clarify how exercise shapes B cell-related immunity.

The Effect of Moderate-Intensity Physical Exercise on Some Serum Inflammation Markers and the Immune System in Rats Fed Intermittent Fasting with a High-Fat Diet

Background and Objectives: This study aimed to investigate the impact of moderate-intensity physical exercise on serum inflammation markers and the immune system in rats that were fed a high-fat diet (HFD) with intermittent fasting. Materials and Methods: A total of 48 Wistar albino male rats were included in the study and divided into eight groups, each consisting of six rats. Group 1 served as the control group (CG), receiving a standard diet. Group 2 followed the standard nutrition program with intermittent fasting (CG + IF). Group 3 underwent exercise with a standard diet (CG + E). Group 4 underwent both a standard diet with intermittent fasting and exercise (CG + IF + E). Group 5 was fed a high-fat diet (HFD). Group 6 received a high-fat diet with intermittent fasting (HFD + IF). Group 7 followed a high-fat diet with exercise (HFD + E). Group 8 underwent both a high-fat diet with intermittent fasting and exercise (HFD + IF + E). The study lasted for 8 weeks. Results: The results of the analysis show that lymphocyte cell levels in groups HFD + IF, HFD + IF, and HFD + IF + E were higher compared to groups CG-HFD (p < 0.05). Additionally, B lymphocyte and monocyte cell levels were higher in group HFD + IF + E compared to groups CG, CG + IF, and CG + IF + E, as well as CG, CG + IF, and CG + E, respectively. TNF-α levels were significantly higher in group HFD compared to the other groups. Furthermore, IL 10 levels were higher in group HFD + IF + E compared to the other groups. Conclusions: These findings indicate that moderate exercise and intermittent fasting, particularly in groups fed a high-fat diet, increased anti-inflammatory cytokine levels, and certain immune system cell counts, while decreasing pro-inflammatory cytokine levels.

[Physical Activity and Mental Health in the Elderly]

Physical Activity and Mental Health in the Elderly Abstract. The aging process is closely linked to physiological changes. These physiological changes may lead to an increased vulnerability for developing somatic and mental disorders. Reduced physical activity/sedentary behaviour can enhance this process. In contrast, physical training and sports counteract this process, in particular in the elderly, who may thus gain or maintain a younger biological age. Physical fitness is associated with better mental health in the elderly. Sports and physical activity over the course of life have shown to be of preventive value concerning the development of depression and dementia in old age. Also late-life depression and cognitive impairment (MCI, mild cognitive impairment) can be improved by regular, continuous physical exercise. Some data furthermore suggest that even patients with dementia benefit from physical exercise, especially on behalf of the behavioural and psychic symptoms of dementia (BPSD).

Type and Intensity as Key Variable of Exercise in Metainflammation diseases: A Review

Monocyte and lymphocyte subpopulations exhibit functions that vary between the anti- and pro-inflammatory spectrum, such as classic CD16- and non-classical CD16+ monocytes, as well as T helper 2 lymphocytes (Th2), the Th1/Th17 lymphocytes ratio, and T regulatory lymphocytes (Treg). Metabolic disease-associated inflammation is accompanied by an imbalance in monocyte and lymphocyte phenotypes and functionality, as well as a stronger proportion of inflammatory subpopulations. These changes appear to be important for the development and progression of diseases like diabetes and cardiovascular disease. On the other hand, the regular practice of physical exercise is an important tool to restore the functionality of monocytes and lymphocytes, and to balance the subtypes ratio. However, key variables regarding exercise prescription, such as the type of exercise, intensity, and volume differentially impact on the acute and chronic immune response in individuals diagnosed with meta inflammation diseases. Here, we discuss the impact of different physical exercise protocols, acutely and chronically, on monocytes and lymphocytes of individuals with metabolic disease-associated inflammation. In this review, we focus on the best effects of different exercise protocols to dose the "exercise pill" in different inflammatory status.

A pilot study of high-intensity interval training in older adults with treatment naïve chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most common leukemia in the USA, affecting predominantly older adults. CLL is characterized by low physical fitness, reduced immunity, and increased risk of secondary malignancies and infections. One approach to improving CLL patients' physical fitness and immune functions may be participation in a structured exercise program. The aims of this pilot study were to examine physical and immunological changes, and feasibility of a 12-week high-intensity interval training (HIIT) combined with muscle endurance-based resistance training on older adults with treatment naïve CLL. We enrolled eighteen participants with CLL aged 64.9 ± 9.1 years and assigned them to groups depending on distance lived from our fitness center. Ten participants (4 M/6F) completed HIIT and six participants (4 M/2F) completed a non-exercising control group (Controls). HIIT consisted of three 30-min treadmill sessions/week plus two concurrent 30-min strength training sessions/week. Physical and immunological outcomes included aerobic capacity, muscle strength and endurance, and natural killer (NK) cell recognition and killing of tumor cells. We confirmed feasibility if > 70% of HIIT participants completed > 75% of prescribed sessions and prescribed minutes, and if > 80% of high-intensity intervals were at a heart rate corresponding to at least 80% of peak aerobic capacity (VO_2peak). Results are presented as Hedge's G effect sizes (g), with 0.2, 0.5 and 0.8 representing small, medium and large effects, respectively. Following HIIT, leg strength (g = 2.52), chest strength (g = 1.15) and seated row strength (g = 3.07) were 35.4%, 56.1% and 39.5% higher than Controls, respectively, while aerobic capacity was 3.8% lower (g = 0.49) than Controls. Similarly, following HIIT, in vitro NK-cell cytolytic activity against the K562 cell line (g = 1.43), OSU-CLL cell line (g = 0.95), and autologous B-cells (g = 1.30) were 20.3%, 3.0% and 14.6% higher than Controls, respectively. Feasibility was achieved, with HIIT completing 5.0 ± 0.2 sessions/week and 99 ± 3.6% of the prescribed minutes/week at heart rates corresponding to 89 ± 2.8% of VO_2peak. We demonstrate that 12-weeks of supervised HIIT combined with muscle endurance-based resistance training is feasible, and that high adherence and compliance are associated with large effects on muscle strength and immune function in older adults with treatment naïve CLL.Trial registration: NCT04950452.

Effect of Moderate Intensity Exercise on Infection Rates in Individuals with Primary Immunodeficiency Disease: A Preliminary Pilot Randomized Investigation

PURPOSE

Individuals with a diagnosis of primary immunodeficiency disease (PID) have poorer health-related quality of life (HRQoL) compared with healthy individuals. Regular moderate exercise enhances immune function and wellbeing. Whether exercise at recommended levels for the general population is tolerated by individuals diagnosed with PID, without adverse effects, is unknown and warrants investigation.

METHODS

A prospective randomized preliminary pilot investigation with individuals diagnosed with PID was undertaken; participants were assigned to either an exercise (n = 18) or control group (n = 16). The exercise group completed an eight-week, semi-customized, home-based, moderate intensity exercise program, while the control group engaged in routine activities. Participants completed recall surveys assessing infection rates and non-routine medical care over 8 weeks prior to the eight-week intervention.

RESULTS

Given recruitment issues, the study was underpowered. Thus, as expected, no difference between groups was observed.

CONCLUSION

This preliminary pilot investigation provides the foundation for a large scale, appropriately powered, randomized controlled trial to investigate the effect of moderate exercise on infection rates and non-routine medical care for individuals with PID. Recommendations are made to strengthen the methodology of future investigations on the effects of exercise on the immune function and quality of life for individuals diagnosed with PID.

Exercise and the immune system: taking steps to improve responses to cancer immunotherapy

The remarkable success of cancer immunotherapies has provided new hope to cancer patients. Unfortunately, a significant proportion of patients remain unable to respond to immunotherapy or maintain durable clinical responses. The lack of objective responses likely results from profound immune dysfunction often observed in patients with cancer. There is substantial evidence that exercise and physical activity can reduce incidence and improve outcomes in cancer patients. As the immune system is highly responsive to exercise, one potential avenue to improve immune function is through exercise and physical activity. A single event of dynamic exercise results in the substantial mobilization of leukocytes with increased functional capacities into the circulation. Chronic, or long-term, exercise leads to higher physical fitness in terms of greater cardiorespiratory function and/or muscle strength and endurance. High aerobic capacity, as measured by maximal oxygen uptake, has been associated with the reduction of dysfunctional T cells and improvements in the abundance of some T cell populations. To be sure, however, the mechanisms of exercise-mediated immune changes are both extensive and diverse. Here, we examine the evidence and theorize how acute and chronic exercise could be used to improve responses to cancer immunotherapies including immune checkpoint inhibitors, dendritic cell vaccines, natural killer cell therapies, and adoptive T cell therapies such as chimeric antigen receptor (CAR) T cells. Although the parameters of optimal exercise to yield defined outcomes remain to be determined, the available current data provide a compelling justification for additional human studies and clinical trials investigating the adjuvant use of exercise in immuno-oncology.

The Effects of Lifestyle and Diet on Gut Microbiota Composition, Inflammation and Muscle Performance in Our Aging Society

Living longer is associated with an increased risk of chronic diseases, including impairments of the musculoskeletal and immune system as well as metabolic disorders and certain cancers, each of which can negatively affect the relationship between host and microbiota up to the occurrence of dysbiosis. On the other hand, lifestyle factors, including regular physical exercise and a healthy diet, can affect skeletal muscle and immune aging positively at all ages. Accordingly, health benefits could partly depend on the effect of such interventions that influence the biodiversity and functionality of intestinal microbiota. In the present review, we first discuss the physiological effects of aging on the gut microbiota, immune system, and skeletal muscle. Secondly, we describe human epidemiological evidence about the associations between physical activity and fitness and the gut microbiota composition in older adults. The third part highlights the relevance and restorative mechanisms of immune protection through physical activity and specific exercise interventions during aging. Fourth, we present important research findings on the effects of exercise and protein as well as other nutrients on skeletal muscle performance in older adults. Finally, we provide nutritional recommendations to prevent malnutrition and support healthy active aging with a focus on gut microbiota. Key nutrition-related concerns include the need for adequate energy and protein intake for preventing low muscle mass and a higher demand for specific nutrients (e.g., dietary fiber, polyphenols and polyunsaturated fatty acids) that can modify the composition, diversity, and metabolic capacity of the gut microbiota, and may thus provide a practical means of enhancing gut and systemic immune function.

Impact of exercise on the immune system and outcomes in hematologic malignancies

Exercise is increasingly recognized as important to cancer care. The biology of how exercise improves outcomes is not well understood, however. Studies show that exercise favorably influences the immune system in healthy individuals (neutrophils, monocytes, natural killer cells, T cells, and a number of cytokines). Thus, exercise in patients with hematologic cancer could significantly improve immune function and tumor microenvironment. We performed a literature search and identified 7 studies examining exercise and the immune environment in hematologic malignancies. This review focuses on the role of exercise and physical activity on the immune system in hematologic malignancies and healthy adults.

Effects of Regular Physical Activity on the Immune System, Vaccination and Risk of Community-Acquired Infectious Disease in the General Population: Systematic Review and Meta-Analysis

Background

Regular physical activity is the prime modality for the prevention of numerous non-communicable diseases and has also been advocated for resilience against COVID-19 and other infectious diseases. However, there is currently no systematic and quantitative evidence synthesis of the association between physical activity and the strength of the immune system.

Objective

To examine the association between habitual physical activity and (1) the risk of community-acquired infectious disease, (2) laboratory‐assessed immune parameters, and (3) immune response to vaccination.

Methods

We conducted a systemic review and meta-analysis according to PRISMA guidelines. We searched seven databases (MEDLINE, Embase, Cochrane CENTRAL, Web of Science, CINAHL, PsycINFO, and SportDiscus) up to April 2020 for randomised controlled trials and prospective observational studies were included if they compared groups of adults with different levels of physical activity and reported immune system cell count, the concentration of antibody, risk of clinically diagnosed infections, risk of hospitalisation and mortality due to infectious disease. Studies involving elite athletes were excluded. The quality of the selected studies was critically examined following the Cochrane guidelines using ROB2 and ROBINS_E. Data were pooled using an inverse variance random-effects model.

Results

Higher level of habitual physical activity is associated with a 31% risk reduction (hazard ratio 0.69, 95% CI 0.61–0.78, 6 studies, N = 557,487 individuals) of community-acquired infectious disease and 37% risk reduction (hazard ratio 0.64, 95% CI 0.59–0.70, 4 studies, N = 422,813 individuals) of infectious disease mortality. Physical activity interventions resulted in increased CD4 cell counts (32 cells/µL, 95% CI 7–56 cells/µL, 24 studies, N = 1112 individuals) and salivary immunoglobulin IgA concentration (standardised mean difference 0.756, 95% CI 0.146–1.365, 7 studies, N = 435 individuals) and decreased neutrophil counts (704 cells/µL, 95% CI 68–1340, 6 studies, N = 704 individuals) compared to controls. Antibody concentration after vaccination is higher with an adjunct physical activity programme (standardised mean difference 0.142, 95% CI 0.021–0.262, 6 studies, N = 497 individuals).

Conclusion

Regular, moderate to vigorous physical activity is associated with reduced risk of community-acquired infectious diseases and infectious disease mortality, enhances the first line of defence of the immune system, and increases the potency of vaccination.

Protocol registration

The original protocol was prospectively registered with PROSPERO (CRD42020178825).

Supplementary Information

The online version contains supplementary material available at 10.1007/s40279-021-01466-1.

Effects of a 6 Week Low-Dose Combined Resistance and Endurance Training on T Cells and Systemic Inflammation in the Elderly

With increasing age, the immune system undergoes a remodeling process, affecting the shift of T cell subpopulations and the development of chronic low-grade inflammation. Clinically, this is characterized by increased susceptibility to infections or development of several diseases. Since lifestyle factors can play a significant role in reducing the hallmarks of immune aging and inflammation, we investigated the effect of a 6 week low-dose combined resistance and endurance training program. Forty participants (70.3 ± 5.0 years) were randomly assigned to either a training (TG) or control group (CG) and performed a controlled low-threshold and care-oriented 6-week-long combined resistance and endurance training program. Changes in anthropometrics as well as strength capacity were measured. In subgroups of TG and CG, T cells and their subpopulations (CD4⁺, CD8⁺, naïve, central, effector memory, T-EMRA) were analyzed by flow cytometry. The changes of various plasma cytokines, chemokines, growth factors and adipokines were analyzed by luminex assays. The exercise program was followed by an increase in strength capacities. Participants of TG showed an increase of the CD4⁺/CD8⁺ T cell ratio over time (p < 0.05). Significant decreases in systemic levels of interleukin (IL-) 6, IL-8, IL-10 and vascular endothelial growth factor (VEGF) (p < 0.05) were observed for participants of TG over time. Even short-term and low-threshold training can reduce some of the hallmarks of immune aging in elderly and thus could be beneficial to stimulate immunity. The specific characteristics of the program make it easily accessible to older people, who may benefit in the longer term in terms of their immunocompetence.

The impact of high-intensity interval exercise training on NK-cell function and circulating myokines for breast cancer prevention among women at high risk for breast cancer

Purpose

Preclinical evidence suggests that natural killer cell (NK-cell) function and myokines facilitate the protective effects of exercise for breast cancer prevention. Since higher-intensity exercise acutely promotes greater mobilization and larger changes in NK-cell cytotoxicity than lower-intensity, high-intensity interval training (HIIT) might offer increased immune protection compared to moderate-intensity continuous-training (MICT). This study compared a 12-week HIIT program to a 12-week MICT program and usual care on changes in resting NK-cell function and circulating myokines among women at high risk for breast cancer.

Methods

Thirty-three women were randomized to HIIT, MICT, or usual care, for a supervised exercise intervention. Blood was collected at baseline and end-of-study. The cytotoxic activity of CD3−/CD56+ NK-cells against the K562 target cell line in vitro was determined by flow cytometry. Circulating myokines (IL-15, IL-6, irisin, OSM, osteonectin, IL-7) were assessed with luminex multiplex assays and ELISA. One-way ANOVA and paired sample t-tests assessed between- and within-group differences, respectively. Pearson correlation coefficients determined relationships between baseline fitness and change variables.

Results

Significant differences were not observed between groups for change in NK-cell function or circulating myokines (p > 0.05). Significant correlations were only observed for baseline peak aerobic capacity (ml/kg/min) and change in NK-cell-specific lysis (r = − 0.43, p = 0.02) and hemacytotoxicity for the total sample (r = − 0.46, p = 0.01).

Conclusion

Our findings suggest that exercise intensity may not significantly impact change in resting NK-cell function and circulating myokines among women at high risk for breast cancer. Structured exercise training may have a larger impact on NK-cell function in those with lower levels of cardiorespiratory fitness.

Clinical trial registration: NCT02923401; Registered on October 4, 2016

Strength Endurance Training but Not Intensive Strength Training Reduces Senescence-Prone T Cells in Peripheral Blood in Community-Dwelling Elderly Women

Aging is characterized by a progressive decline in immune function known as immunosenescence. Although the causes of immunosenescence are likely to be multifactorial, an age-associated accumulation of senescent T cells and decreased naive T-cell repertoire are key contributors to the phenomenon. On the other hand, there is a growing consensus that physical exercise may improve immune response in aging. However, the optimum training modality required to obtain beneficial adaptations in older subjects is lacking. Therefore, we aimed to investigate the effects of exercise modality on T-cell phenotypes in older women. A total of 100 women (aged ≥ 65 years) were randomized to either intensive strength training (80% of one-repetition maximum ), strength endurance training (40% one-repetition maximum), or control (stretching exercise) for 2-3 times per week during 6 weeks. The T-cell percentages and absolute counts were determined using flow cytometry and a hematology analyzer. C-reactive protein was measured using immunonephelometry. We report for the first time that 6 weeks of strength endurance training significantly decreased the basal percentage and absolute counts of senescence-prone T cells, which was positively related to the number of training sessions performed. Conceivably, training protocols with many repetitions-at a sufficiently high external resistance-might assist the reduction of senescence-prone T cells in older women.

Relationship between heat stress exposure and some immunological parameters among foundry workers

Occupational exposure to heat stress may lead to changes in blood cell count. The objective of this retrospective descriptive-analytical field study is to investigate the relationship between heat stress exposure and some immunological parameters among foundry workers. This study was carried out on 55 subjects of which, 35 were working in a foundry unit (exposed group) and 20 were working in a computer numerical control (CNC) machining unit (control group). The measurement method consisted of taking 10 cc of the subjects' blood between 10 am and 2 pm and then performing the automated blood cell counting and enzyme-linked immunosorbent assay (ELISA) on the sample. Environmental parameters such as noise levels, lighting, and the wet-bulb globe temperature (WBGT) index were measured at the subjects' workstations. All measurements were made in the first half of the month of July. The mean WBGT index was 22.5 ± 2.16 °C for the control group and 32.97 ± 3.22 °C for the exposed group. The laboratory test results show a significant decrease in white blood cell count and lymphocyte levels and a significant increase in neutrophil levels and neutrophil to lymphocyte ratio in exposed group compared with control ones (P < 0.05). IgM levels decrease under heat stress, but we do not observe significant differences between IgG and IgA levels between two groups. A significant negative correlation was observed between white blood cell count, lymphocyte levels, and IgM concentration with WBGT index and significant positive correlation was observed between neutrophil and neutrophil to lymphocyte ratio with WBGT index. No significant correlation was observed between sound pressure levels and light intensity with studied immunological parameters. In conclusion, under heat stress conditions, leukocytes levels and immunoglobulin concentration may reduce and it may weaken and suppress the human immune system.

Physical Activity and Diet Shape the Immune System during Aging

With increasing age, the immune system undergoes a remodeling process, termed immunosenescence, which is accompanied by considerable shifts in leukocyte subpopulations and a decline in various immune cell functions. Clinically, immunosenescence is characterized by increased susceptibility to infections, a more frequent reactivation of latent viruses, decreased vaccine efficacy, and an increased prevalence of autoimmunity and cancer. Physiologically, the immune system has some adaptive strategies to cope with aging, while in some settings, maladaptive responses aggravate the speed of aging and morbidity. While a lack of physical activity, decreased muscle mass, and poor nutritional status facilitate immunosenescence and inflammaging, lifestyle factors such as exercise and dietary habits affect immune aging positively. This review will discuss the relevance and mechanisms of immunoprotection through physical activity and specific exercise interventions. In the second part, we will focus on the effect of dietary interventions through the supplementation of the essential amino acid tryptophan, n-3 polyunsaturated fatty acids, and probiotics (with a special focus on the kynurenine pathway).

Alterations in the innate immune system due to exhausting exercise in intensively trained rats

It is known that intensive physical activity alters the immune system's functionality. However, the influence of the intensity and duration of exercise needs to be studied in more depth. We aimed to establish the changes in the innate immune response induced by two programmes of intensive training in rats compared to sedentary rats. A short training programme included 2 weeks of intensive training, ending with an exhaustion test (short training with exhaustion, S-TE). A second training programme comprised 5-week training including two exhaustion tests and three trainings per week. In this case, immune status was assessed before (T), immediately after (TE) and 24 h after (TE24) an additional final exhaustion test. Biomarkers such as phagocytic activity, macrophage cytokine and reactive oxygen species (ROS) production, and natural killer (NK) cell activity were quantified. S-TE was not enough to induce changes in the assessed innate immunity biomarkers. However, the second training was accompanied by a decrease in the phagocytic activity, changes in the pattern of cytokine secretion and ROS production by macrophages and reduced NK cell proportion but increased NK cytotoxic activity. In conclusion, a 5-week intense training programme, but not a shorter training, induced alterations in the innate immune system functionality.

Effects of Exercise on the Tumour Microenvironment

Epidemiological evidence suggests that exercise improves survival in cancer patients. However, much is still unknown regarding the mechanisms of this positive survival effect and there are indications that exercise may not be universally beneficial for cancer patients. The key to understanding in which situations exercise is beneficial may lie in understanding its influence on the tumour microenvironment (TME)-and conversely, the influence of the tumour on physical functioning. The TME consists of a vast multitude of different cell types, mechanical and chemical stressors and humoral factors. The interplay of these different components greatly influences tumour cell characteristics and, subsequently, tumour growth rate and aggression. Exercise exerts whole-body physiological effects and can directly and indirectly affect the TME. In this chapter, we first discuss the possible role of exercise capacity ('fitness') and exercise adaptability on tumour responsiveness to exercise. We summarise how exercise affects aspects of the TME such as tumour perfusion, vascularity, hypoxia (reduced oxygenation) and immunity. Additionally, we discuss the role of myokines and other circulating factors in eliciting these changes in the TME. Finally, we highlight unanswered questions and key areas for future research in exercise oncology and the TME.

Effects of exercise type on estrogen, tumor markers, immune function, antioxidant function, and physical fitness in postmenopausal obese women

This study aims to identify the effects of exercise type on estrogen, tumor markers, immune function, antioxidant function, and physical fitness in postmenopausal obese women. The subjects were 30 post-menopausal obese women with body fat percentage higher than 30%. Participants were divided into aerobic exercise group (n=10; age, 53.70±3.37 years), resistance exercise group (n=10; age, 52.20±2.15 years), and control group (n=10; age, 52.50±2.68 years). Estrogen and growth hormone showed no significant difference in the aerobic exercise group, resistance exercise group, and control group. Tumor marker alpha-fetoprotein was increased in the aerobic exercise, resistance exercise, and control groups (P<0.01). The metabolic syndrome risk factor was decreased in the aerobic and resistance exercise groups, which was shown by the reduction of weight (P<0.001), body fat percentage (P<0.001), waist circumference (P<0.05), and increase of high density lipoprotein-cholesterol (P<0.001). natural killer cell activity was increased in the aerobic exercise group, resistance exercise group, and control group (P<0.001). Oxidative stress was decreased in the aerobic exercise group, resistance exercise group, and control group (P<0.001). Maximum oxygen uptake was increased in the aerobic and resistance exercise groups, but aerobic exercise was more effective (P<0.05). Knee isokinetic extensor muscle was increased in both the aerobic and resistance exercise groups (P<0.001). Aerobic and resistance exercise of postmenopausal obese women can be considered an effective intervention program to prevent metabolic syndrome and improve physical fitness.

Energy balance and gastrointestinal cancer: risk, interventions, outcomes and mechanisms

Obesity increases the risk of multiple gastrointestinal cancers and worsens disease outcomes. Conversely, strong inverse associations have emerged between physical activity and colon cancer and possibly other gastrointestinal malignancies. The effect of weight loss interventions - such as modifications of diet and/or physical activity or bariatric surgery - remains unclear in patients who are obese and have gastrointestinal cancer, although large clinical trials are underway. Human intervention studies have already shed light on potential mechanisms underlying the energy balance-cancer relationship, with preclinical models supporting emerging pathway effects. Central to interventions that reduce obesity or increase physical activity are pluripotent cancer-preventive effects (including reduced systemic and adipose tissue inflammation and angiogenesis, altered adipokine levels and improved insulin resistance) that directly interface with the hallmarks of cancer. Other mechanisms, such as DNA repair, oxidative stress and telomere length, immune function, effects on cancer stem cells and the microbiome, could also contribute to energy balance effects on gastrointestinal cancers. Although some mechanisms are well understood (for instance, systemic effects on inflammation and insulin signalling), other areas remain unclear. The current state of knowledge supports the need to better integrate mechanistic approaches with preclinical and human studies to develop effective, personalized diet and exercise interventions to reduce the burden of obesity on gastrointestinal cancer.

Effects of Acute and Chronic Exercise on Immunological Parameters in the Elderly Aged: Can Physical Activity Counteract the Effects of Aging?

Immunosenescence is characterized by deterioration of the immune system caused by aging which induces changes to innate and adaptive immunity. Immunosenescence affects function and phenotype of immune cells, such as expression and function of receptors for immune cells which contributes to loss of immune function (chemotaxis, intracellular killing). Moreover, these alterations decrease the response to pathogens, which leads to several age-related diseases including cardiovascular disease, Alzheimer's disease, and diabetes in older individuals. Furthermore, increased risk of autoimmune disease and chronic infection is increased with an aging immune system, which is characterized by a pro-inflammatory environment, ultimately leading to accelerated biological aging. During the last century, sedentarism rose dramatically, with a concomitant increase in certain type of cancers (such as breast cancer, colon, or prostate cancer), and autoimmune disease. Numerous studies on physical activity and immunity, with focus on special populations (i.e., people with diabetes, HIV patients) demonstrate that chronic exercise enhances immunity. However, the majority of previous work has focused on either a pathological population or healthy young adults whilst research in elderly populations is scarce. Research conducted to date has primarily focused on aerobic and resistance exercise training and its effect on immunity. This review focuses on the potential for exercise training to affect the aging immune system. The concept is that some lifestyle strategies such as high-intensity exercise training may prevent disease through the attenuation of immunosenescence. In this context, we take a top-down approach and review the effect of exercise and training on immunological parameters in elderly at rest and during exercise in humans, and how they respond to different modes of training. We highlight the impact of these different exercise modes on immunological parameters, such as cytokine and lymphocyte concentration in elderly individuals.

Effects of Physical Exercise on Markers of Cellular Immunosenescence: A Systematic Review

Aging affects negatively the immune system, defined as immunosenescence, which increases the susceptibility of elderly persons to infection, autoimmune disease, and cancer. There are strong indications that physical exercise in elderly persons may prevent the age-related decline in immune response without significant side effects. Consequently, exercise is being considered as a safe mode of intervention to reduce immunosenescence. The aim of this review was to appraise the existing evidence regarding the impact of exercise on surface markers of cellular immunosenescence in either young and old humans or animals. PubMed and Web of Science were systematically screened, and 28 relevant articles in humans or animals were retrieved. Most of the intervention studies demonstrated that an acute bout of exercise induced increases in senescent, naïve, memory CD4⁺ and CD8⁺ T-lymphocytes and significantly elevated apoptotic lymphocytes in peripheral blood. As regards long-term effects, exercise induced increased levels of T-lymphocytes expressing CD28⁺ in both young and elderly subjects. Few studies found an increase in natural killer cell activity following a period of training. We can conclude that exercise has considerable effects on markers of cellular aspects of the immune system. However, very few studies have been conducted so far to investigate the effects of exercise on markers of cellular immunosenescence in elderly persons. Implications for immunosenescence need further investigation.

EFEITOS DO EXERCÍCIO FÍSICO SOBRE O SISTEMA IMUNE DE MULHERES PÓS-MENOPAUSADAS: REVISÃO SISTEMÁTICA

RESUMO As mulheres na menopausa sofrem mudanças endócrinas que acarretam uma série de disfunções, inclusive a atenuação da resposta imune. Nesse sentido, realizou-se uma revisão sistemática da literatura que objetivou buscar ensaios clínicos randomizados (ECR) que verificassem o efeito do exercício físico na imunomodulação em mulheres pós-menopausadas. Utilizaram-se as bases de dados eletrônicas Medline/PubMed, SciELO, Scopus, Lilacs e Bireme, com as seguintes palavras-chave: humans, immune system, physical activity, exercise, physical fitness, postmenopause e postmenopausal period. Utilizou-se como critério de exclusão dos títulos e resumos, os artigos que deixavam claro não tratar do efeito do exercício/atividade física sobre o sistema imune e artigos que estudaram mulheres com câncer e/ou diabetes. Foram incluídos sete artigos para análise. As intervenções duraram de seis meses a 19,9 anos, com amostras variando de 18 a 421 pessoas. Todos os estudos utilizaram o exercício aeróbio moderado como intervenção. Apenas um estudo utilizou medida subjetiva para avaliar o sistema imune, sendo que os demais estudos utilizaram medidas bioquímicas diretas. Com relação ao efeito do exercício sobre a imunomodulação, 57,1% dos ECR concluíram que o exercício físico atuou positivamente sobre o sistema imune de mulheres menopausadas e nenhum mostrou efeito negativo. A proteína C reativa e a contagem de células imunológicas foram as mais pesquisadas, com quatro estudos cada, nos quais, apenas um de cada variável mostrou associação significativa na diminuição desses parâmetros. Três estudos pesquisaram a variável interleucina-6 e dois, a amiloide A, sem demonstrar associação significativa; dos dois estudos que avaliaram imunoglobulinas, apenas um mostrou associação para o aumento da imunoglobulina A. Concluiu-se que é pouco provável que o exercício aeróbio prejudique o sistema imune de mulheres menopausadas e é necessária a realização de novos ECR que objetivem verificar as mudanças na imunomodulação dessa população e que abranjam diferentes volumes e tipos de exercício físico.

Exercise-Dependent Regulation of NK Cells in Cancer Protection

Natural killer (NK) cells are the most responsive immune cells to exercise, displaying an acute mobilization to the circulation during physical exertion. Recently, exercise-dependent mobilization of NK cells was found to play a central role in exercise-mediated protection against cancer. Here, we review the link between exercise and NK cell function, focusing on circulating exercise factors and additional effects, including vascularization, hypoxia, and body temperature in mediating the effects on NK cell functionality. Exercise-dependent mobilization and activation of NK cells provides a mechanistic explanation for the protective effect of exercise on cancer, and we propose that exercise represents a potential strategy as adjuvant therapy in cancer, by improving NK cell recruitment and infiltration in solid tumors.

Exercise enhances wound healing and prevents cancer progression during aging by targeting macrophage polarity

Physical activity, which can include regular and repetitive exercise training, has been shown to decrease the incidence of age-related diseases. Aging is characterized by aberrant immune responses, including impaired wound healing and increased cancer risk. The behavior and polarized phenotype of tissue macrophages are distinct between young and old organisms. The balance of M1 and M2 macrophages is altered in the aged tissue microenvironment, with a tilt towards an M2-dominant macrophage population, as well as its associated signaling pathways. These M2-type responses may result in unresolved inflammation and create an environment that impairs wound healing and is favorable for cancer growth. We discuss the concept that exercise training can improve the regulation of macrophage polarization and normalize the inflammatory process, and thereby exert anticancer effects and enhance wound healing in older humans.

Plasma polychlorinated biphenyl concentrations and immune function in postmenopausal women

BACKGROUND

Polychlorinated biphenyl (PCB) exposure has been associated with non-Hodgkin lymphoma in several studies, and the immune system is a potential mediator.

OBJECTIVES

We analyzed associations of plasma PCBs with immune function measures. We hypothesized that higher plasma PCB concentrations are associated with lower immune function cross-sectionally, and that increases in PCB concentrations over a one year period are associated with decreases in immune function.

METHODS

Plasma PCB concentrations and immune function [natural killer (NK) cell cytotoxicity and PHA-induced T-lymphocyte proliferation (PHA-TLP)] were measured at baseline and one year in 109 postmenopausal overweight women participating in an exercise intervention study in the Seattle, Washington (USA) area. Mixed models, with adjustment for body mass index and other potential confounders, were used to estimate associations of PCBs with immune function cross-sectionally and longitudinally.

RESULTS

Associations of PCBs with immune function measures differed across groups of PCBs (e.g., medium- and high-chlorinated and dioxin-like [mono-ortho-substituted]) and by the time frame for the comparison (cross-sectional vs. longitudinal). Higher concentrations of medium- and high-chlorinated PCBs were associated with higher PHA-TLP cross-sectionally but not longitudinally. The mean decrease in 0.5 µg/mL PHA-TLP/50.0 pmol/g-lipid increase in dioxin-like PCBs over one year was 51.6 (95% confidence interval 2.7, 100.5; P=0.039). There was no association between plasma PCBs and NK cytotoxicity.

CONCLUSIONS

These results do not provide strong evidence of impaired cellular immunity from PCB exposure. Larger longitudinal studies with greater variability in PCB exposures are needed to further examine temporal associations of PCBs with immune function.

Preventing or reversing immunosenescence: can exercise be an immunotherapy?

There is now a strong body of evidence demonstrating that aging is accompanied by severe alterations in the immune system, a process known as immunosenescence. Among these changes are alterations in T-cell subpopulation size, cytokine secretion pattern, cell replicative capacity and antibody production, all of which culminate in a proinflammatory state called 'inflammaging' and a diminished capacity to respond to new antigens. These alterations are closely related to the increased mortality and morbidity rates observed in this population. However, the role of exercise on the prevention or treatment of immunosenescence is virtually unknown. Data gathered from the literature regarding the effects of physical activity on immune system aging are still limited and conflicting, with existing reports either advocating benefits or asserting a lack of evidence. Exercise as part of a healthy lifestyle has already been shown to provide long-term benefits with regard to cardiovascular, cognitive, psychosocial and other aspects of the elderly. If positive effects are also observed for immunosenescence, exercise could be a highly cost-effective measure to improve human quality of life compared with other strategies currently being pursued.

Physical activity and its relation to cancer risk: updating the evidence

Scientific evidence for the primary prevention of cancer caused by physical activity of regular moderate-intensity or greater is rapidly accumulating in this field. About 300 epidemiologic studies on the association between physical activity and cancer risk have been conducted worldwide. The objectives of this paper were three-fold: (i) to describe briefly the components of physical activity and its quantification; (ii) to summarize the most important conclusions available from comprehensive reports, and reviews of the epidemiologic individual and intervention studies on a role physical activity in cancer prevention; (iii) to present proposed biological mechanisms accounting for effects of activity on cancer risk. The evidence of causal linked physical activity and cancer risk is found to be strong for colon cancer - convincing; weaker for postmenopausal breast and endometrium cancers - probable; and limited suggestive for premenopausal breast, lung, prostate, ovary, gastric and pancreatic cancers. The average risk reductions were reported to be 20-30%. The protective effects of physical activity on cancer risk are hypothesized to be through multiple interrelated pathways: decrease in adiposity, decrease in sexual and metabolic hormones, changes in biomarkers and insulin resistance, improvement of immune function, and reduction of inflammation. As there are several gaps in the literature for associations between activity and cancer risk, additional studies are needed. Future research should include studies dealing with limitations in precise estimates of physical activity and of a lack of consensus on what defines sedentary behavior of individuals and those linked with the proposed biomarkers to cancer risk and controlled exercise intervention trials.

The Influence of Energetic Factors on Biomarkers of Postmenopausal Breast Cancer Risk

Strong and consistent evidence exists that physical activity reduces breast cancer risk by 10-25 %, and several proposed biologic mechanisms have now been investigated in randomized, controlled, exercise intervention trials. Leading hypothesized mechanisms relating to postmenopausal breast cancer include adiposity, endogenous sex hormones, insulin resistance, and chronic low-grade inflammation. In addition, other pathways are emerging as potentially important, including those involving oxidative stress and telomere length, global DNA hypomethylation, immune function, and vitamin D exposure. Recent exercise trials in overweight/obese postmenopausal women implicate weight loss as a mechanism whereby exercise induces favorable changes in circulating estradiol levels and other biomarkers as well. Still it is plausible that some exercise-induced biomarker changes do not require loss of body fat, whereas others depend on abdominal fat loss. We highlight the latest findings from randomized, controlled trials of healthy postmenopausal women, relating exercise to proposed biomarkers for postmenopausal breast cancer risk.

Exercise and the aging immune system

Aging is associated with a decline in the normal functioning of the immune system that is described by the canopy term "immunosenescence". This contributes to poorer vaccine responses and the increased incidence of infection and malignancy seen in the elderly. Regular exercise has been associated with enhanced vaccination responses, lower numbers of exhausted/senescent T-cells, increased T-cell proliferative capacity, lower circulatory levels of inflammatory cytokines ("inflamm-aging"), increased neutrophil phagocytic activity, lowered inflammatory response to bacterial challenge, greater NK-cell cytotoxic activity and longer leukocyte telomere lengths in aging humans, all of which indicate that habitual exercise is capable of regulating the immune system and delaying the onset of immunosenescence. This contention is supported by the majority of animal studies that report improved immune responses and outcomes to viral infections and malignancies due to exercise training. However, whether or not exercise can reverse, as well as prevent, immunosenescence is a contentious issue, particularly because most longitudinal exercise training studies do not report the same positive effects of exercise on immunity that have been widely reported in studies with a cross-sectional design. In this review, we summarize some of the known effects of exercise on immunosenescence, discuss avenues for future research, and provide potential mechanisms by which exercise may help rejuvinate the aging immune system.

Hypoxic exercise training promotes antitumour cytotoxicity of natural killer cells in young men

The cytotoxic functions of NKs (natural killer cells) are critical in enabling the immune system to cope efficiently with malignancy. In the present study, we compared how various exercise regimens without/with hypoxia influence phenotypic characteristics of NK subsets and cytotoxicity of NKs to NPCs (nasopharyngeal carcinoma cells). A total of 60 sedentary males were randomly divided into five groups. Each group (n=12) underwent one of five regimens: normoxic (21% O2) control (N-C), hypoxic (15% O2) control (H-C), normoxic exercise (50% maximal work rate under 21% O2; N-E), hypoxic relative exercise (50% maximal heart rate reserve under 15% O2; H-RE) or hypoxic absolute exercise (50% maximal work rate under 15% O2; H-AE) for 30 min/day, 5 days/week for 4 weeks. The results showed that hypoxic exercise regimens increased pulmonary ventilation and tissue oxygen utilization. Moreover, the H-RE regimen resulted in enhanced aerobic fitness at a less intensive training workload in the H-AE regimen. Before each regimen, strenuous exercise elevated NK perforin/granzyme B content and promoted cytotoxicity of NKs to NPCs. However, the percentage of NKs expressing homing (CD11a)/terminally differentiated (CD57)/inhibitory [KLRG1 (killer cell lectin-like receptor G1)] molecules that entered the bloodstream from peripheral tissues increased following this exercise. After 4 weeks, both the H-AE and H-RE regimens produced an up-regulated expression of memory (CD45RO)/activating (NKG2D) molecules and was accompanied by a decrease in CD57/KLRG1 levels on NKs at rest and after strenuous exercise. Furthermore, the two regimens increased resting and exercise NK perforin/granzyme B content and NK-induced phosphatidylserine exposure of NPCs. In contrast, no significant change in the phenotypic characteristics of blood NK subsets or NK-induced NPC apoptosis was observed in the N-C, H-C and N-E regimens. Therefore we conclude that 15% O2 exercise training reduces terminally differentiated NK subsets and up-regulates the expression of activating molecules and cytotoxic granule proteins in NKs, thereby enhancing the capacity of anti-NPC cytotoxicity by NKs. These findings could help to determine effective hypoxic exercise regimens for improving individual aerobic capacity and simultaneously promoting the natural cytotoxicity of NKs.

Physical activity and breast cancer prevention

Breast cancer is the most commonly diagnosed invasive malignancy and the second leading cause of cancer death in women. This chapter considers epidemiologic evidence regarding the association between physical activity and breast cancer risk from 73 studies conducted around the world. Across these studies there was a 25% average risk reduction amongst physically active women as compared to the least active women. The associations were strongest for recreational activity, for activity sustained over the lifetime or done after menopause, and for activity that is of moderate to vigorous intensity and performed regularly. There is also some evidence for a stronger effect of physical activity amongst postmenopausal women, women who are normal weight, have no family history of breast cancer, and are parous. It is likely that physical activity is associated with decreased breast cancer risk via multiple interrelated biologic pathways that may involve adiposity, sex hormones, insulin resistance, adipokines, and chronic inflammation. Future research should include prospective observational epidemiologic studies relating proposed biomarkers to breast cancer risk and also randomized controlled trials to examine how physical activity influences the proposed biomarkers. Exercise trials will provide more clarity regarding the appropriate type, dose, and timing of activity that relate to breast cancer risk reduction.

State of the epidemiological evidence on physical activity and cancer prevention

BACKGROUND

Physical activity is a modifiable lifestyle risk factor that has the potential to reduce the risk of most major cancer sites.

METHODS

We examined the strength, consistency, dose-response and biological plausibility of an association between physical activity and risk of colon, breast, endometrium, lung, prostate, ovarian, gastric, rectal, pancreatic, bladder, testicular, kidney and haematological cancers. We also estimated the population-attributable risk (PAR) for physical inactivity and cancer in 15 European countries.

RESULTS

There is convincing or probable evidence for a beneficial effect of physical activity on the risk of colon, breast and endometrial cancers. The evidence is weaker for ovarian, lung and prostate cancers and generally either null or insufficient for all remaining cancers. Several hypothesised biological mechanisms include a likely effect of physical activity on insulin resistance, body composition, sex steroid hormones and a possible effect on vitamin D, adipokines, inflammation and immune function. Somewhere between 165,000 and 330,000 cases of the six major cancers (breast, colon, lung, prostate, endometrium and ovarian) could have been prevented in 2008 in Europe alone if the population had maintained sufficient levels of physical activity.

CONCLUSION

There is strong and consistent evidence that physical activity reduces the risk of several of the major cancer sites, and that between 9% and 19% of cancer cases could be attributed to lack of sufficient physical activity in Europe. Public health recommendations for physical activity and cancer prevention generally suggest 30-60 min of moderate or vigorous-intensity activity done at least 5d per week.

Physical activity and gynecologic cancer prevention

This chapter reviews the findings from epidemiologic studies of the associations of physical activity with gynecologic cancers, including those of the endometrium, ovaries, and cervix, and the biologic mechanisms mediating the associations. The epidemiologic evidence to date suggests that physical activity probably protects against endometrial cancer, with a risk reduction of about 20-30% for those with the highest levels of physical activity compared to those with the lowest levels, and that light to moderate physical activity including housework, gardening, or walking for transportation may reduce risk. The role of physical activity in ovarian cancer development remains uncertain, as findings from these studies have been inconsistent with about half the studies suggesting physical activity modestly decreases risk and about half the studies suggesting no association. A recent meta-analysis of studies examining recreational physical activity with ovarian cancer risk estimated a 20% reduced risk for the most active versus least active women. There is mounting evidence that sedentary behaviors such as sitting time probably increase risk of endometrial and ovarian cancers. Overall, there is insufficient evidence to draw a conclusion on a possible role of physical activity in the development of cervical cancer, although a modest influence on risk is possible through effects on sex steroid hormones and immune function. The biologic evidence provides strong support for a protective role of physical activity on cancer of the endometrium, and moderate support for cancer of the ovaries, as these cancers have a strong hormonal etiology. The more established biologic mechanisms that are supported by epidemiologic and experimental data involve endogenous sex hormone levels, insulin-mediated pathways, and maintenance of energy balance.In this chapter, we will discuss the evidence for an association of physical activity with gynecologic cancers including those of the endometrium, ovaries, and cervix. Cancers of the endometrium and ovaries have a strong hormonal etiology (Risch 1998; Kaaks et al. 2002; Lukanova and Kaaks 2005), and physical activity has been postulated as a potential modifiable risk factor for prevention of these cancers because it can influence circulating hormone levels, energy balance, and insulin-mediated pathways that are thought to be important mediators underlying the associations. Few studies have evaluated the association of physical activity with cervical cancer because the main causal factor is infection with certain types of human papillomavirus (HPV), although other hormonal and immune factors are also thought to play a role (Smith et al. 2003; Waggoner 2003). We review the findings from epidemiologic studies that have examined the associations of physical activity with gynecologic cancers, and the biologic mechanisms that might mediate the associations.

Effect of exercise on oxidative stress: a 12-month randomized, controlled trial

PURPOSE

This study examined the effect of a yearlong exercise intervention on F2-isoprostane, a specific marker of lipid peroxidation and a general marker of oxidative stress.

METHODS

In a randomized, controlled trial, 173 overweight or obese, postmenopausal, sedentary women were randomized either to an aerobic exercise intervention (60%-75% observed maximal HR) for > or =45 min.d-1, 5 d.wk-1 (n = 87), or to a stretching control group (n = 86), on an intent-to-treat basis. Baseline and 12-month measures included urinary F2-isoprostane, maximal O2 uptake, body weight, body fat percentage, waist circumference, and intra-abdominal fat surface area. Urine samples were available from 172 and 168 women at baseline and 12 months, respectively.

RESULTS

During the 12-month study, controls minimally changed maximal O2 uptake (+0.2%) and body weight (+0.1 kg), whereas exercisers increased maximal O2 uptake (+13.6%; P < 0.0001 vs controls) and decreased body weight (-1.3 kg; P = 0.007 vs controls). F2-isoprostane increased slightly among controls (+3.3%) and decreased in exercisers (-6.2%), although the effect was not statistically significant (P = 0.26). In planned subgroup analyses, F2-isoprostane decreased linearly with gain in maximal O2 uptake (Ptrend = 0.005) relative to controls; exercisers who increased maximal O2 uptake by >15% decreased F2-isoprostane by 14.1% (P = 0.005 vs controls). A borderline statistically significant trend was observed between decreased waist circumference and F2-isoprostane (P = 0.06). Similar subgroup analyses by 12-month changes in body fat percentage, weight, and intra-abdominal fat were not statistically significant.

CONCLUSIONS

These findings suggest that aerobic exercise, when accompanied by relatively marked gains in aerobic fitness, decreases oxidative stress among previously sedentary older women and that these effects occur with minimal change in mass or body composition.

Physical activity and breast cancer: review of the epidemiologic evidence and biologic mechanisms

Breast cancer is the most commonly diagnosed invasive malignancy and the second leading cause of cancer death in women globally. This review considers epidemiologic evidence regarding the association between physical activity and breast cancer risk. Across these studies there was a 25% average risk reduction among physically active women as compared to the least active women. The associations were strongest for recreational activity, for activity sustained over the lifetime or done after menopause, and for activity that is of moderate to vigorous intensity and performed regularly. There is also some evidence for a stronger effect of physical activity among postmenopausal women, women who are normal weight, have no family history of breast cancer, and are parous. It is likely that physical activity is associated with decreased breast cancer risk via multiple interrelated biologic pathways that may involve adiposity, sex hormones, insulin resistance, adipokines, and chronic inflammation. Future research should include prospective observational epidemiologic studies relating proposed biomarkers to breast cancer risk and also randomized controlled trials to examine how physical activity influences the proposed biomarkers. Exercise trials will provide more clarity regarding the appropriate type, dose, and timing of activity that are related to breast cancer risk reduction.Breast cancer remains a leading cause of cancer incidence and mortality in most developed countries worldwide. While significant international research has examined risk factors for breast cancer, most identified risk factors are nonmodifiable. During the past 20 years, over 90 studies have been conducted worldwide that have examined some aspects of the association between physical activity and breast cancer risk reduction. The purpose of this chapter is to review both the epidemiologic evidence and hypothesized biologic mechanisms whereby physical activity may influence breast cancer risk.

Physical activity as a preventive measure against overweight, obesity, infections, allergies and cardiovascular disease risk factors in adolescents: AFINOS Study protocol

Background

Prior studies addressing the impacts of regular physical activity or sedentary habits on the immune system have been conducted in adults and laboratory settings. Thus, it is practically unknown how a healthy active lifestyle could affect low-grade inflammation processes, infections or allergies in young persons. The AFINOS Study was designed to determine the relationship between the regular physical activity levels of adolescents and overweight, infection, and allergies along with the presence of metabolic and immunological biomarkers of a deteriorated health status. A further objective of the AFINOS Study is to assess the health status and lifestyle habits of an adolescent population in an effort to identify any protective factors that could be used as preventive measures, since many chronic diseases and their associated co-morbidities often persist from adolescence into adulthood.

Methods/Design

This study was conducted as three separate sub-studies in three different populations as follows: (a) Study 1 was performed on a population sample of adolescents; (b) Study 2 on the adolescents' parents; and (c) Study 3 on a subset of the adolescents from Study 1. Study 1 assessed health and lifestyle indicators through a questionnaire administered to a representative sample of adolescents from the Madrid Region (n = 2400) aged 13 to 16 years. In Study 2, the parents of the teenagers participating in Study 1 were required to fill out a questionnaire. Finally in Study 3, body composition, physical activity, health-related physical fitness, and blood measurements were determined in a subset (n = 200) of the individuals included in Study 1.

Discussion

This paper describes the rationale, design, and methodologies used in the AFINOS Study. This multidisciplinary, multicenter study seeks to evaluate several aspects of existing relationships between routine physical activity/sedentary behaviour and several health status markers, specifically those related to the immune system. The results of this cross-sectional study will serve for comparisons with the available data obtained in laboratory settings and in adults. In addition, knowledge regarding the health status and lifestyle habits of Spanish adolescents and their parents will be useful for designing preventive measures.

A yearlong exercise intervention decreases CRP among obese postmenopausal women

PURPOSE

To investigate the effect of a yearlong moderate-intensity aerobic exercise intervention on C-reactive protein (CRP), serum amyloid A (SAA), and interleukin 6 (IL-6) among overweight or obese postmenopausal women.

METHODS

In a randomized controlled trial, 115 postmenopausal, overweight or obese, sedentary women, aged 50-75 yr were randomized to an aerobic exercise intervention of moderate-intensity (60%-75% observed maximal HR), for > or = 45 min x d(-1), 5 d x wk (n = 53), or to a 1-d x wk(-1) stretching control (n = 62), on an intent-to-treat basis. CRP, SAA, and IL-6 were measured at baseline, at 3 months, and at 12 months.

RESULTS

From baseline to 12 months, CRP decreased 10% in exercisers and increased 12% in controls (P = 0.01); no effects were observed for SAA and IL-6. Among participants at baseline who were obese (body mass index (BMI) > or = 30 kg x m(-2)) or had abdominal obesity (waist circumference (WC) > or = 88 cm), exercise resulted in a more pronounced reduction in CRP (BMI > or = 30 kg x m(-2), P = 0.002; WC > or = 88 cm, P < 0.0001), borderline for SAA (BMI > or = 30 kg x m(-2), P = 0.08; WC > or = 88 cm, P = 0.04); no intervention effects were observed among women who did not have these characteristics. Overall, weight loss was minimal in the exercise intervention ( approximately 1.8 kg). Linear trends were observed between CRP and 12-month changes in aerobic fitness (Ptrend = 0.006), exercise adherence (Ptrend = 0.004), percentage body fat (Ptrend = 0.002), body weight (Ptrend = 0.002), WC (Ptrend = 0.02), and intra-abdominal fat (Ptrend = 0.03).

CONCLUSIONS

A moderate-intensity exercise intervention reduced CRP for 12 months among women who were obese at baseline. These findings support the role of exercise in modulating inflammatory processes that are related to increased risk of chronic disease among obese women.