The BASES expert statement on exercise, immunity, and infection

An individual's level of physical activity influences their risk of infection, most likely by affecting immune function. Regular moderate exercise reduces the risk of infection compared with a sedentary lifestyle, but very prolonged bouts of exercise and periods of intensified training are associated with an increased risk of infection. There are several lifestyle, nutritional, and training strategies that can be adopted to limit the extent of exercise-induced immunodepression and minimize the risk of infection. This expert statement provides a background summarizing the evidence together with extensive conclusions and practical guidelines.     

特殊人群的运动、感染风险和免疫机能

有关运动与免疫的研究,大都集中在研究运动对普通人群和运动员上呼吸道感染的影响以及免疫机能的影响,这些研究的大部分案例都是针对年轻人和健康人群的。那么,运动免疫学领域还很大,尤其是对那些疾病、亚健康和特殊年龄段的人群的研究仍是相对薄弱的地方。对特殊人群(HIV感染人群、老年人、儿童、肥胖和糖尿病)的运动、感染风险和免疫机能进行综述。     

运动与免疫系统研究进展

运动对机体免疫功能有急慢性以及正负性影响。有规律的适度运动可增强免疫功能而降低感染风险。急性运动后肌源性IL-6释放增加,IL-10上升从而抑制细胞免疫功能。急性运动增强自然杀伤细胞活性但是降低白细胞的吞噬功能。长时间的高强度运动可能会通过抑制黏膜IgA分泌而增加上呼吸道感染风险。定期补充抗氧化剂如维生素C和E以及在运动过程中摄入碳水化合物有助于预防免疫抑制。平衡营养饮食匹配合理的运动计划可支持和促进免疫系统。     

Recommendations to maintain immune health in athletes

Numerous studies over the last 35 years report an increase in upper respiratory infection (URI) symptoms in athletes during periods of heavy training and competition. Challenges athletes face such as heavy exercise and life stress influence immune function via activation of the hypothalamic–pituitary–adrenal axis and the sympathetic nervous system and the resulting immunoregulatory hormones. Both innate and acquired immunity are often reported to decrease transiently in the hours after heavy exertion, typically 15–70%: prolonged heavy training sessions in particular have been shown to decrease immune function; potentially providing an ‘open window’ for opportunistic infections. Whether the observed changes in immunity with acute strenuous exercise or periods of heavy training account for the increased susceptibility to URI symptoms remains contentious. Nevertheless, there is little doubt that URI symptoms hinder athletic training and competition; underpinning the need to identify the prominent risk factors and appropriate countermeasures. Recent studies have identified prominent risk factors, including: intensified training in the winter; long-haul travel; low energy availability; high levels of psychological stress and anxiety; and depression. Given the shared pathways and effector limbs for the body’s response to physical and psychological challenges, it is logical that psychological strain influences immunity and illness incidence in athletes under heavy training; indeed, stress and anxiety have recently been shown to modify the immune response to exercise. This mini-review provides new insights and evidence-based recommendations for coping with the various challenges that athletes encounter on immune health, including: heavy exercise; life stress; sleep disruption; environmental extremes and nutritional deficits.     

Motives for lifestyle and exercise activities: A comparison using the theory of planned behaviour

Abstract

Regular exercise and lifestyle physical activity are often used interchangeably or combined in physical activity messaging based on evidence for their relatively equivalent health outcomes. However, differences between their motivational correlates are relatively unexplored. The purpose of this study was to compare the motives towards lifestyle physical activity and exercise and their relationship with behaviour using the Theory of Planned Behaviour (TPB). The participants were a sample of undergraduate students (n=150) who completed measures of the TPB framed in terms of exercise and lifestyle physical activity and self-reported physical activity measures with similar framing. Results identified marked differences between the instrumental attitudes towards the two activities showing instrumental attitudes towards exercise to be higher (P<0.01; d=0.68). Most importantly, exercise had larger TPB–behaviour correlations (P<0.01; q=0.15–0.20) compared with lifestyle physical activity, but follow-up analyses by intensity (strenuous, moderate, mild) showed that these differences were only present at strenuous intensity. Our results suggest that the correlates for the two types of physical activity may differ. Although more research is necessary, this may affect the efficacy of promotion campaigns that do not tailor content exclusively for either exercise or lifestyle physical activity.     

急性运动降低感染风险的免疫调节机制

由于新型冠状病毒(2019-nCoV)感染的肺炎疫情暴发,人们将居家运动作为提高免疫力与保持健康的重要手段,运动与免疫的关系再度受到关注。一般认为,在充分恢复的前提下进行规律的中高强度运动可提高免疫功能,而急性运动(acute exercise)可能抑制免疫功能并增加感染风险。急性运动后外周血淋巴细胞计数及功能降低、免疫球蛋白A水平分泌减少被认为是运动抑制免疫的理论基础。但目前这种独立于非运动因素影响免疫功能增加感染风险的认识受到了现有研究的挑战。急性运动可通过应激反应将淋巴细胞亚群迅速动员至循环中,运动结束后,淋巴细胞亚群又会迅速迁移至外周组织。淋巴细胞的重新分布(lymphocyte redeployment)可能是一种进化保守的免疫机制,这一过程强化了外周组织的免疫监视与调节功能,有助于提升机体抵抗感染能力。因此,从这一视角就急性运动对机会性感染风险及免疫功能影响的现状进行综述。     

Correlates of Physical Activity Behavior in Rural Youth

Abstract

The purpose of this study was to identify correlates of physical activity behavior in a sample of rural, predominantly African American youth. Three hundred sixty-one fifth-grade students from two rural counties in South Carolina (69% African American, median age = 11 years) completed a questionnaire designed to measure beliefs and social influences regarding physical activity, physical activity self-efficacy, perceived physical activity habits of family members and friends, and access to exercise and fitness equipment at home. After school physical activity and television watching were assessed using the Previous Day Physical Activity Recall (PDPAR). Students were classified as physically active according to a moderate physical activity standard: two or more 30-min blocks at an intensity of 3 METs (metabolic equivalents) or greater, and a vigorous physical activity standard: one or more 30-min blocks at an intensity of 6 METs or greater. According to the moderate physical activity standard, 34.9% of students were classified as low-active. Multivariate analysis revealed age, gender, television watching, and exercise equipment at home to be significant correlates of low activity status. According to the vigorous physical activity standard, 32.1% of the students were classified as low-active. Multivariate analysis revealed age, gender, television watching, and self-efficacy with respect to seeking support for physical activity to be significant correlates of low activity status. In summary, gender and the amount of television watching were found to be the most important correlates of physical activity in rural, predominantly African American youth.     

Mannose-binding lectin 2 gene polymorphism and susceptibility to upper respiratory tract infection among endurance athletes

Abstract

The aim of this study was to investigate the influence of mannose-binding lectin 2 (MBL2)-exon-1 gene polymorphisms on upper respiratory tract infection (URTI) incidence among endurance athletes. To this end, 100 healthy elite male athletes participating in the study were classified as either healthy or prone to frequent URTI. Blood samples, DNA isolation, multiplex polymerase chain reaction (PCR) and conventional PCR-RFLP were performed. Genomic DNA was extracted from peripheral leukocytes of whole blood samples using the QIAmp DNA Blood Mini Kit. For comparison of the distribution of genotypes between two groups and for estimating odds ratios (OR) for URTI susceptibility in relation to the MBL2-exon-1 polymorphism, Pearson's chi-square and logistic regression method were used, respectively. The MBL2-exon-1 genotype distribution differed between athletes with URTI and healthy athletes (χ² = 7.81, p = 0.02). The AO and AO + OO genotypes of MBL2 were observed at a greater frequency in the illness-prone group compared with the healthy group (34.04% vs. 11.32%). In conclusion, findings from this study have identified a potential role of genetic variation in influencing the risk for URTI in athletic populations and single-nucleotide polymorphisms (SNPs) in the MBL2-exon-1 genes were associated with an altered risk profile. These measures may have a predictive value in the identification of individuals who are more likely to experience recurrent infections when exposed to high physical stress in the areas of athletic endeavour.     

Running for your life: A review of physical activity and cardiovascular disease risk reduction in individuals with schizophrenia

Individuals with schizophrenia have a greater risk for cardiometabolic risk factors (e.g. central obesity, insulin resistance, hypertension and dyslipidaemia), cardiovascular diseases and mortality. This risky profile may be explained by the adverse effects of antipsychotic medications and an unhealthy lifestyle (e.g. smoking, poor nutrition and low physical activity). In the general population, physical activity has been shown to be the optimal strategy to improve both cardiometabolic parameters and cardiorespiratory fitness levels. Accordingly, an emerging literature of non-pharmacological interventions (e.g. cognitive behavioural therapy, diet and physical activity) has been studied in individuals with schizophrenia. Therefore, the purpose of this review was 1) to conduct a critical literature review of non-pharmacological interventions that included some kind of physical activity (including supervised and unsupervised exercise training) and target cardiometabolic risk factors in individuals with schizophrenia. 2) To describe the contribution of physical activity alone by reviewing trials of supervised exercise training programmes only. A literature review via systematic keyword search for publications in Medline, PubMed, Embase and PsycINFO was performed. Many non-pharmacological interventions are efficient in reducing cardiovascular disease risk factors when combined with physical activity. Supervised physical activity has been successful in decreasing cardiovascular disease risk, and aerobic interval training appears to provide more benefits by specifically targeting cardiorespiratory fitness levels. In conclusion, physical activity is an effective strategy for addressing cardiovascular disease risk in individuals with schizophrenia. Long-term studies are needed to evaluate the feasibility and impact of exercise training programmes in individuals with schizophrenia.     

Immune function and exercise

This review will examine the effects of exercise and training on immune func-tion and will discuss the methodological problems that limit the interpretation of many exercise immunology studies. Acute bouts of exercise cause a tempo-rary depression of various aspects of immune function, such as neutrophil oxidative burst, lymphocyte proliferation, monocyte MHC class II expression, and natural killer cell cytotoxic activity, that will usually last for approximately three to 24 hours after exercise, depending on the intensity and duration of the exercise bout. Post-exercise immune function depression is most pronounced when the exercise is continuous, prolonged (<1.5 hours), of moderate to high intensity (55-75% VO₂max), and performed without food intake. Periods of intensified training that result in overreaching have been shown to chronically depress immune function—i.e., immune cell functions measured at rest are still depressed 24 hours after the last exercise bout. Although elite athletes are not clinically immune deficient, it is possible that the combined effects of small changes in several immune parameters may compromise resistance to common minor illnesses such as upper respiratory tract infection. Protracted immune depression linked with prolonged training may determine susceptibility to infection, particularly at times of major competitions.     

Girolamo Cardano and De sanitate tuenda: A Renaissance Physician's Perspective on Exercise

Abstract

The concepts of exercise as presented in De sanitate tuenda (Care of Health), 1560, written by the Renaissance physician, Girolamo Cardano (1501–1576), were the focus of the inquiry. In this work, as well as in his personal and professional life, Cardano was an advocate of physical activity for the development of physical and mental well-being. The benefits accrued from participation were: the harmonious development of mind and body; good health; emotional stability; a strong, firm, beautiful body; and a long, robust life. Physical exercise was perceived as a lifelong task ranging from childhood to old age, with activities geared for the needs and limitations of each age grouping. Vigorous activities were recommended for both children and youth. As one grew older, moderate physical exercise with longer rest periods was advised. A comparison of this work with Sir Thomas Elyot's Castel of Helth, 1541, revealed that Cardano was significant in the realm of Renaissance exercise for his advocacy of physical exercise for all ages, particularly the forty to seventy age group, as well as for the delineation of appropriate activities for this older adult group.     

Mucosal immunity and upper respiratory tract infections during a 24-week competitive season in young ice hockey players

The aim of this study was to examine upper respiratory tract infections (URTI) and their associations with resting saliva and blood immune and endocrine parameters in ice hockey players. Twenty-seven participants (age 16.5 ± 0.5 years) completed the 24-week study period. The counts/concentrations of immune and endocrine markers were compared between healthy-prone athletes (≤2 episodes of URTI during the study period) and illness-prone athletes (≥3 episodes of URTI) and between the URTI state (when athletes had infections) and the healthy state (the time without URTI). There were no differences in concentration/counts of saliva and blood immune and endocrine parameters between the illness-prone and illness-free athletes. Athletes had significantly lower sIgA, sIgA1 and sIgA2 concentrations (sIgA: 119.88 ± 66.88, 144.10 ± 75.0 µg/ml; sIgA1: 90.2 ± 40.64, 108.44 ± 29.8 U; sIgA2: 67.58 ± 30.1, 80.3 ± 25.61 U, respectively) and significantly higher WBC, neutrophil, monocyte and eosinophil count values and IL-1ra concentration at the time when they had symptoms of URTI than in the period without symptoms of infections. There were no differences in salivary cortisol concentration between the period of URTI symptoms and the period without URTI symptoms. In conclusion, we observed lower concentrations of salivary immunoglobulins and higher levels of blood immune parameters during URTI in athletes, which may confirm the suppression of mucosal immunity and initiation responses to pathogenic infections by innate immunity.     

Mass media representations of the evidence as a possible deterrent to recommending exercise for the treatment of depression: Lessons five years after the extraordinary case of TREAD-UK

Exercise or physical activity are recommended options within stepped-care treatment models for depression. However, few physicians present these options to patients, in part because of the impression that the supporting evidence is weak or inconsistent. We speculate that the coocurrence of “counter-messaging” and deficient critical appraisal may lead to such impressions. We focus on TREAD-UK (ISRCTN16900744), the largest trial to investigate “whether physical activity can be an effective treatment for depression within primary care”. In media statements, researchers declared that exercise was ineffective in lowering depression. We examined (a) the results of the trial, critiques, and rejoinders, (b) the impact on internet searches, and (c) whether TREAD-UK was critically appraised, as reflected in citing articles. We show that the results of TREAD-UK were misrepresented. The media campaign resulted in a fourfold increase in relevant internet searches. Of articles characterising the results, 57% adopted the interpretation that exercise failed to lower depression, whereas only 17% were critiques. We identify similarities to media portrayals of the OPERA (ISRCTN43769277), DEMO (NCT00103415), and DEMO-II trials (NCT00695552). We note a disconcerting trend of media campaigns that misrepresent the effects of exercise on depression and call for increased scrutiny in peer reviewing both pre- and post-publication.     

Validating the multimedia activity recall for children and adolescents in a large New Zealand sample

Abstract

The aim of the study was to validate the self-report Multimedia Activity Recall for Children and Adolescents (MARCA) against accelerometry for the assessment of physical activity in New Zealand children. Participants (n = 716, 10–18 years) recalled 3–4 days of activity using the MARCA and underwent a partially overlapping 7-day accelerometry protocol during a national survey. Spearman correlation coefficients (ρ) assessed the association between accelerometer-derived counts per minute and MARCA-derived physical activity level and time in locomotion. Both data sources estimated time spent in light and moderate–vigorous physical activity. Association and agreement between methods for light physical activity and moderate–vigorous physical activity was assessed using correlations and Bland–Altman plots respectively, and paired t-tests conducted. Accelerometer-derived activity counts were moderately correlated with both MARCA-derived physical activity level and locomotion (ρ = 0.38, P < 0.0001). The correlation between methods was –0.14 for light physical activity and 0.28 for moderate–vigorous physical activity (P < 0.0001). The MARCA overestimated moderate–vigorous physical activity compared with accelerometry (120 min, P < 0.0001), which increased as moderate–vigorous physical activity time increased. Some sex and ethnicity (Māori [indigenous] versus non-Māori) differences were observed. Overall, the MARCA indicated moderate validity for assessment of physical activity level, locomotion and moderate–vigorous physical activity and poor validity for assessment of light physical activity. This was comparable to other self-report tools. The MARCA has utility for future large-scale research.     

健康老龄化的挑战——衰弱:概念框架、风险评估及体力活动干预研究

在系统梳理衰弱概念及理论模型、衰弱风险评估工具的基础上,着重分析目前体力活动和衰弱的剂效关系及干预效果。结果表明:1)依据衰弱循环模型、累积健康缺陷模型、整合概念模型等理论框架,国际上提出了衰弱的概念。2)衰弱身体表型和衰弱指数是最常用的衰弱评估工具。3)体力活动对衰弱具有较好的干预效果,能延缓并逆转衰弱发展进程,其中多组分的综合运动类型、团体训练的运动组织形式和中等强度运动能有效地改善衰弱。4)横断面和纵向追踪研究显示,体力活动和衰弱之间存在"剂量-效应"关系,中高强度体力活动(moderate to vigorous physical activity,MVPA)和衰弱呈负相关,从事MVPA的时间越久,衰弱的发生风险越低。5)为深入开展和加强我国衰弱领域的研究,建议:开发适合我国老年人的衰弱评估工具;多学科协作,开展衰弱的运动干预实践;基于我国传统健身功法,探寻运动干预衰弱的中国方案。     

Benefits of achieving vigorous as well as moderate physical activity recommendations: evidence from heart rate complexity and cardiac vagal modulation

The aim of this study was to examine differences in traditional heart rate variability measurements and heart rate complexity (sample entropy) in young adults grouped by objectively measured achievement of either moderate or both moderate and vigorous physical activity recommendations. Of 168 young adults tested (86 females, 82 males; age 20.5 ± 1.2 years), 119 achieved only recommendations for moderate physical activity (moderate group) and 49 achieved recommendations for both moderate and vigorous physical activity (vigorous group). Analysis of covariance controlling for sex, weekly minutes of moderate physical activity, and percentage of body fat was used to assess between-group differences in heart rate variability and heart rate complexity. Logistic regression analysis was used to determine the group characteristics that best predicted high heart rate complexity and vagal indices of heart rate variability. The majority of the autonomic measures were higher (P < 0.05) in the vigorous group, and regression analysis showed that vigorous physical activity was the only multivariate predictor of higher heart rate complexity and higher heart rate variability. Young adults engaged in regular vigorous physical activity were more than twice as likely to have high heart rate complexity than those involved in predominantly moderate exercise. These findings suggest that vigorous physical activity is more closely associated with high heart rate complexity than moderate physical activity in young adults.     

Physical exercise in the prevention and treatment of Alzheimer's disease

Dementia is one of the greatest global challenges for health and social care in the 21st century. Alzheimer's disease (AD), the most common type of dementia, is by no means an inevitable consequence of growing old. Several lifestyle factors may increase, or reduce, an individual's risk of developing AD. Much has been written over the ages about the benefits of exercise and physical activity. Among the risk factors associated with AD is a low level of physical activity. The relationship between physical and mental health was established several years ago. In this review, we discuss the role of exercise (aerobic and resistance) training as a therapeutic strategy for the treatment and prevention of AD. Older adults who exercise are more likely to maintain cognition. We address the main protective mechanism on brain function modulated by physical exercise by examining both human and animal studies. We will pay especial attention to the potential role of exercise in the modulation of amyloid β turnover, inflammation, synthesis and release of neurotrophins, and improvements in cerebral blood flow. Promoting changes in lifestyle in presymptomatic and predementia disease stages may have the potential for delaying one-third of dementias worldwide. Multimodal interventions that include the adoption of an active lifestyle should be recommended for older populations.     

The Association of Objectively Determined Physical Activity Behavior Among Adolescent Female Friends

The purpose of this study was to examine the extent to which physical activity among adolescent female friends is interdependent. The participants were 318 adolescent girls with a mean age of 16.0 years (range: 15–18 years). Pedometry was used to assess physical activity over 4 days. The relationship between an individual girl and her first-nominated reciprocal friend's physical activity level was moderate (r = 0.45, 90% confidence interval = 0.31, 0.56), when the friendship was nonreciprocal it was trivial (r = -.06, 90% confidence interval = -.36. .25). Friends' physical activity levels explained between 27% and 32% of an individual's pedometer-determined physical activity level. Reciprocity of friendship is an important variable to consider when understanding the relationship between adolescent female friends' physical activity. When friendships are reciprocal, there is a stronger relationship between friends' physical activity.     

Effects of an unsupervised pedometer-based physical activity program on daily steps of adults with moderate to severe asthma: a randomized controlled trial

Supervised exercise has shown benefits for subjects with asthma, but little is known about the effectiveness of unsupervised physical activity on this population. We investigated the effects of a 12-week unsupervised pedometer-based physical activity program on daily steps and on clinical and psychological parameters of adults with asthma. Clinically stable adults with moderate to severe asthma were encouraged to take daily 30-minute walks and were randomized to pedometer and control groups. The pedometer group received pedometers and individualized daily step targets. Changes in daily steps (average of steps taken during six consecutive days), six-minute walk test (6MWT), health-related quality of life, asthma control and anxiety and depression levels were assessed 12 weeks after intervention and 24–28 weeks after randomization. Thirty-seven participants were recruited and 30 completed the intervention. At 12 weeks, the groups differed significantly in daily steps (adjusted average difference, 2488 steps; 95% confidence interval [CI], 803 to 4172; p = 0.005) and in the 6MWT (adjusted average difference, 21.9 m; 95% CI, 6.6 to 37.3; p = 0.006). These differences were not significant 24–28 weeks after randomization. The program was effective in increasing daily steps of adults with moderate to severe asthma 12 weeks after intervention.     

体育锻炼活动量对中等职业学校学生健康影响的分析

本文提高中等职业技术学校学生体育锻炼及健康现状为研究目的,主要运用文献资料法、问卷调查法、测试法及数理统计法等研究方法,对河南省部分中等职业技术学校学生参与体育锻炼活动量和心理应对方式及体质健康的现状进行调查,研究发现：中等职业技术学生参与体育锻炼活动量、心理应对方式存在性别差异,且男同学的体育活动量大于女生,女同学更倾向于采用＂幻想＂、＂求助＂的应付方式;不同体育锻炼量对体质健康的影响存在差异性,中等体育锻炼量有助于身体健康的提高。