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.     

Exercise,nutrition and immune function

Strenuous bouts of prolonged exercise and heavy training are associated with depressed immune cell function. Furthermore, inadequate or inappropriate nutrition can compound the negative influence of heavy exertion on immunocompetence. Dietary deficiencies of protein and specific micronutrients have long been associated with immune dysfunction. An adequate intake of iron, zinc and vitamins A, E, B6 and B12 is particularly important for the maintenance of immune function, but excess intakes of some micronutrients can also impair immune function and have other adverse effects on health. Immune system depression has also been associated with an excess intake of fat. To maintain immune function, athletes should eat a well-balanced diet sufficient to meet their energy requirements. An athlete exercising in a carbohydrate-depleted state experiences larger increases in circulating stress hormones and a greater perturbation of several immune function indices. Conversely, consuming 30–60?g carbohydrate?·?h^?1 during sustained intensive exercise attenuates rises in stress hormones such as cortisol and appears to limit the degree of exercise-induced immune depression. Convincing evidence that so-called ‘immune-boosting’ supplements, including high doses of antioxidant vitamins, glutamine, zinc, probiotics and Echinacea, prevent exercise-induced immune impairment is currently lacking.     

Effects of exercise intensity and duration on the excess post-exercise oxygen consumption

Abstract

Recovery from a bout of exercise is associated with an elevation in metabolism referred to as the excess post-exercise oxygen consumption (EPOC). A number of investigators in the first half of the last century reported prolonged EPOC durations and that the EPOC was a major component of the thermic effect of activity. It was therefore thought that the EPOC was a major contributor to total daily energy expenditure and hence the maintenance of body mass. Investigations conducted over the last two or three decades have improved the experimental protocols used in the pioneering studies and therefore have more accurately characterized the EPOC. Evidence has accumulated to suggest an exponential relationship between exercise intensity and the magnitude of the EPOC for specific exercise durations. Furthermore, work at exercise intensities ≥50 – 60% [Vdot]O_2max stimulate a linear increase in EPOC as exercise duration increases. The existence of these relationships with resistance exercise at this stage remains unclear because of the limited number of studies and problems with quantification of work intensity for this type of exercise. Although the more recent studies do not support the extended EPOC durations reported by some of the pioneering investigators, it is now apparent that a prolonged EPOC (3 – 24 h) may result from an appropriate exercise stimulus (submaximal: ≥50 min at ≥70% [Vdot]O_2max; supramaximal: ≥6 min at ≥105% [Vdot]O_2max). However, even those studies incorporating exercise stimuli resulting in prolonged EPOC durations have identified that the EPOC comprises only 6 – 15% of the net total oxygen cost of the exercise. But this figure may need to be increased when studies utilizing intermittent work bouts are designed to allow the determination of rest interval EPOCs, which should logically contribute to the EPOC determined following the cessation of the last work bout. Notwithstanding the aforementioned, the earlier research optimism regarding an important role for the EPOC in weight loss is generally unfounded. This is further reinforced by acknowledging that the exercise stimuli required to promote a prolonged EPOC are unlikely to be tolerated by non-athletic individuals. The role of exercise in the maintenance of body mass is therefore predominantly mediated via the cumulative effect of the energy expenditure during the actual exercise.     

Exercise, nutrition and immune function

Strenuous bouts of prolonged exercise and heavy training are associated with depressed immune cell function. Furthermore, inadequate or inappropriate nutrition can compound the negative influence of heavy exertion on immunocompetence. Dietary deficiencies of protein and specific micronutrients have long been associated with immune dysfunction. An adequate intake of iron, zinc and vitamins A, E, B6 and B12 is particularly important for the maintenance of immune function, but excess intakes of some micronutrients can also impair immune function and have other adverse effects on health. Immune system depression has also been associated with an excess intake of fat. To maintain immune function, athletes should eat a well-balanced diet sufficient to meet their energy requirements. An athlete exercising in a carbohydrate-depleted state experiences larger increases in circulating stress hormones and a greater perturbation of several immune function indices. Conversely, consuming 30-60 g carbohydrate x h(-1) during sustained intensive exercise attenuates rises in stress hormones such as cortisol and appears to limit the degree of exercise-induced immune depression. Convincing evidence that so-called 'immune-boosting' supplements, including high doses of antioxidant vitamins, glutamine, zinc, probiotics and Echinacea, prevent exercise-induced immune impairment is currently lacking.     

Nutritional strategies to counter stress to the immune system in athletes, with special reference to football

Although epidemiological data indicate that athletes are at increased risk of upper respiratory tract infection during periods of heavy training and the 1 - 2 week period following endurance race events, there is very limited information on the responses to football training and match-play. For several hours after heavy exertion, components of both the innate (e.g. natural killer cell activity and neutrophil oxidative burst activity) and adaptive (e.g. T and B cell function) immune system exhibit suppressed function. Although such responses to football training and competition do not appear to be as pronounced, variations in immune cell numbers and function are reported in professional footballers over the course of a season. Attempts have been made through nutritional means (e.g. glutamine, vitamins C and E, and carbohydrate supplementation) to attenuate immune changes following intensive exercise and thus lower the risk of upper respiratory tract infection. Carbohydrate supplementation during heavy exercise has emerged as a partial countermeasure and attenuates increases in blood neutrophil counts, stress hormones, and inflammatory cytokines, but has little effect on decrements in salivary IgA output or natural killer cell function. Animal research indicates that other nutritional components such as beta-glucan, quercetin, and curcumin warrant human investigations to determine if they are effective countermeasures to exercise-induced immune dysfunction.     

运动训练对热应激大鼠免疫机能的影响

为了探讨运动和热应激对大鼠白介素2（IL-2）等免疫指标的影响，对大鼠进行为期6周的中等强度负荷运动训练，并在运动末次施加热应激，测定大鼠外周血液白介素2（IL-2）含量、胸腺指数、脾脏指数。结果：（1）运动热应激组大鼠血清中IL-2含量、胸腺指数、脾脏指数显著低于对照组；（2）运动热应激组与热应激组相比，运动热应激组大鼠血清中IL-2含量、胸腺指数、脾脏指数则显著低于对照组；（3）运动热应激与常温急性运动组相比。运动热应激组的大鼠血清中IL-2含量、胸腺指数、脾脏指数显著低于对照组。结论：（1）长时间运动热应激时机体免疫机能受到损伤程度明显增加；（2）在常温下进行中等强度的运动训练，可以适当提高机体的耐热性，降低免疫抑制和损伤。     

Effects of exercise intensity and duration on the excess post-exercise oxygen consumption

Recovery from a bout of exercise is associated with an elevation in metabolism referred to as the excess post-exercise oxygen consumption (EPOC). A number of investigators in the first half of the last century reported prolonged EPOC durations and that the EPOC was a major component of the thermic effect of activity. It was therefore thought that the EPOC was a major contributor to total daily energy expenditure and hence the maintenance of body mass. Investigations conducted over the last two or three decades have improved the experimental protocols used in the pioneering studies and therefore have more accurately characterized the EPOC. Evidence has accumulated to suggest an exponential relationship between exercise intensity and the magnitude of the EPOC for specific exercise durations. Furthermore, work at exercise intensities >or=50-60% VO2max stimulate a linear increase in EPOC as exercise duration increases. The existence of these relationships with resistance exercise at this stage remains unclear because of the limited number of studies and problems with quantification of work intensity for this type of exercise. Although the more recent studies do not support the extended EPOC durations reported by some of the pioneering investigators, it is now apparent that a prolonged EPOC (3-24 h) may result from an appropriate exercise stimulus (submaximal: >or=50 min at >or=70% VO2max; supramaximal: >or=6 min at >or=105% VO2max). However, even those studies incorporating exercise stimuli resulting in prolonged EPOC durations have identified that the EPOC comprises only 6-15% of the net total oxygen cost of the exercise. But this figure may need to be increased when studies utilizing intermittent work bouts are designed to allow the determination of rest interval EPOCs, which should logically contribute to the EPOC determined following the cessation of the last work bout. Notwithstanding the aforementioned, the earlier research optimism regarding an important role for the EPOC in weight loss is generally unfounded. This is further reinforced by acknowledging that the exercise stimuli required to promote a prolonged EPOC are unlikely to be tolerated by non-athletic individuals. The role of exercise in the maintenance of body mass is therefore predominantly mediated via the cumulative effect of the energy expenditure during the actual exercise.     

Promoting training adaptations through nutritional interventions

Training and nutrition are highly interrelated in that optimal adaptation to the demands of repeated training sessions typically requires a diet that can sustain muscle energy reserves. As nutrient stores (i.e. muscle and liver glycogen) play a predominant role in the performance of prolonged, intense, intermittent exercise typical of the patterns of soccer match-play, and in the replenishment of energy reserves for subsequent training sessions, the extent to which acutely altering substrate availability might modify the training impulse has been a key research area among exercise physiologists and sport nutritionists for several decades. Although the major perturbations to cellular homeostasis and muscle substrate stores occur during exercise, the activation of several major signalling pathways important for chronic training adaptations take place during the first few hours of recovery, returning to baseline values within 24 h after exercise. This has led to the paradigm that many chronic training adaptations are generated by the cumulative effects of the transient events that occur during recovery from each (acute) exercise bout. Evidence is accumulating that nutrient supplementation can serve as a potent modulator of many of the acute responses to both endurance and resistance training. In this article, we review the molecular and cellular events that occur in skeletal muscle during exercise and subsequent recovery, and the potential for nutrient supplementation (e.g. carbohydrate, fat, protein) to affect many of the adaptive responses to training.     

Exercise-induced hypoalgesia: Pain tolerance,preference and tolerance for exercise intensity,and physiological correlates following dynamic circuit resistance exercise

Previous research has demonstrated significant decreases in pain perception in healthy individuals following both aerobic and upper body resistance exercise, but research on circuit training has been limited. The purpose of the study was to determine the effects of a strenuous bout of dynamic circuit resistance exercise on pain threshold and pain tolerance in conjunction with changes in blood lactate levels, heart rate (HR), and perceived exertion. A sample of 24 college-age students participated in 2 sessions: (1) a maximal strength testing session and (2) a circuit training bout of exercise that consisted of 3 sets of 12 repetitions with a 1:1 work to rest ratio at 60% one-repetition maximum (1-RM) predicted from a three-repetition maximum (3-RM) for 9 exercises. Participants exhibited increases in pain tolerance, blood lactate levels, HR and perceived exertion following resistance exercise. Preference for exercise intensity was positively correlated with lactate post exercise and tolerance for exercise intensity was positively correlated with pain tolerance and lactate post exercise. In conclusion, this is the first study to demonstrate increases in pain tolerance following a dynamic circuit resistance exercise protocol and disposition for exercise intensity may influence lactate and pain responses to circuit resistance exercise.     

反复离心运动对大鼠骨骼肌损伤和蛋白质降解机制的影响

目的:探讨连续离心运动训练对骨骼肌中Calpain和Ubiquitin含量的影响及其与骨骼肌损伤之间的关系;方法:雄性SD大鼠29只随机分为对照组、离心训练后即刻组、24 h组和7天组.训练组大鼠连续进行7天的下坡跑运动,分别在末次训练后即刻,24 h和第7天取股四头肌,测定股四头肌的超微结构、血清LDH和CK活性以及骨骼肌中Calpaim-1、Calpain-2和Ubiquitin含量;结果:1)7天离心训练后即刻和24h,股四头肌超微结构的损伤性变化呈渐进性加重,离心训练后24 h组出现明显的肌丝坏死.训练后第7天仍不能完全恢复.血清CK和LDH活性的变化与大鼠股四头肌超微结构的变化相一致.2)与对照组相比,末次训练后即刻骨骼肌中Calpain-1、Calpain-2和Ubiquitin含量均显著升高;训练后24 h,Calpain-1和Calpanin-2含量进一步升高,其中,Calpain-1显著高于对照组和训练后24 h组,Calpain-2虽显著高于对照组,但与训练后即刻组相比无显著性差异;而Ubiquitin含量显著低于训练后即刻组.训练后第7天,Calpain-1和Calpain-2含量显著低于训练后24 h组,但仍然高于对照组;而Ubiquitin含量虽高于训练后24 h组和对照组,但无显著性差异;结论:1)连续的离心运动可能对骨骼肌纤维的损伤产生一定的累加作用;2)短期连续的离心训练后,骨骼肌中Calpain和Ubiquitin的动态变化几乎与骨骼肌超微结构的动态变化相一致.离心运动训练导致骨骼肌中Calpain和Ubiquitin含量的增加,可能是导致骨骼肌累积性损伤的重要机制.     

The effects of carbohydrate supplementation during repeated bouts of prolonged exercise on saliva flow rate and immunoglobulin A

The purpose of this study was to assess the effect of carbohydrate (CHO) feeding during different periods of two 90-min cycling bouts (the first bout began at 09:00?h and the second bout began at 13:30?h) at 60% maximal oxygen uptake ([Vdot]O_2max) on saliva flow rate and saliva immunoglobulin A (sIgA) responses to the second exercise bout. The study consisted of three investigations: carbohydrate supplementation during (1) the first hour of the recovery interval (CHO-REC), (2) during the first bout of exercise and (3) during the second bout of exercise. Each investigation included two trials completed in a counterbalanced order and separated by at least 4 days. Participants consumed a lemon-flavoured 10% w/v carbohydrate beverage or placebo (22?ml?·?kg^?1 body mass) in the first hour of the recovery interval (n = 8) and 500?ml just before exercise, followed by 250?ml every 20?min during exercise in the first (n = 9) and second exercise bouts (n = 9). Timed unstimulated saliva samples were collected at 10?min before exercise, after 48?–?50?min of exercise and during the last 2?min of exercise, at 1?h post exercise, 2?h post exercise (first exercise bout only), and 18?h post exercise (second exercise bout only). Venous blood samples were taken 5?min before exercise and immediately after exercise for both exercise bouts in all trials. The main findings of the present study were as follows. First, carbohydrate ingestion during both exercise bouts, but not during the recovery interval, better maintained plasma glucose concentrations and attenuated the increase in plasma adrenaline and cortisol concentrations after the second exercise bout compared with placebo. Second, carbohydrate feeding had no effect on saliva flow rate and sIgA secretion rate compared with placebo. Third, saliva flow rate and sIgA concentration returned to pre-exercise bout 1 values within 2?h in all trials. Fourth, there was no delayed effect of exercise on oral immunity. These findings suggest that carbohydrate ingestion during the first or second bout of exercise, but not during the recovery interval, is likely to better maintain plasma glucose concentrations and attenuate the responses of plasma stress hormones to a second exercise bout than ingestion of fluid alone. Two bouts of 90?min cycling at 60% [Vdot]O_2max on the same day appears to inhibit saliva flow rate during the second exercise bout but does not alter sIgA transcytosis. Our results show that carbohydrate ingestion during any period of two prolonged exercise bouts does not induce different effects on oral immunity compared with placebo.     

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.     

Muscle performance following an acute bout of plyometric training combined with low or high intensity weight exercise

Abstract

To determine the time course of performance responses after an acute bout of plyometric exercise combined with high and low intensity weight training, a 3-group (including a control group), repeated-measures design was employed. Changes in performance were monitored through jumping ability by measuring countermovement and squat jumping, and strength performance assessment through isometric and isokinetic testing of knee extensors (at two different velocities). Participants in both experimental groups performed a plyometric protocol consisting of 50 jumps over 50 cm hurdles and 50 drop jumps from a 50 cm plyometric box. Additionally, each group performed two basic weight exercises consisting of leg presses and leg extensions at 90–95% of maximum muscle strength for the high intensity group and 60% of maximum muscle strength for the low intensity group. The results of the study suggest that an acute bout of intense plyometric exercise combined with weight exercise induces time-dependent changes in performance, which are also dependent on the nature of exercise protocol and testing procedures. In conclusion, acute plyometric exercise with weight exercise may induce a substantial decline in jumping performance for as long as 72 hours but not in other forms of muscle strength.     

不同强度训练时男子摔跤运动员血清性激素和皮质醇的变化

研究了24名男子摔跤运动员不同强度训练课时性激素和皮质醇的变化。结果表明,短时间大强度训练课后血清睾酮、皮质醇没有变化;较长时间中等强度训练课后激素变化不明显,训练课后20小时(次日晨)上述指标与训练前比较也无差异,提示这样的训练没有造成体内激素平衡紊乱。在运动训练过程中,适时地监测这些指标,对于评定运动员身体机能和训练负荷以及训练后恢复情况有重要意义。     

Effects of an acute bout of exercise on serum soluble leptin receptor (sOB-R) levels

Abstract

We investigated the effects of an acute bout of exercise on serum soluble leptin receptor (sOB-R) concentrations. Eighteen male participants completed two different exercise sessions with intensities of 25% and 65% maximal aerobic capacity (VO₂max). In addition to the energy expenditure during exercise sessions being measured, blood samples were collected before exercise, and immediately, at 24 h, and at 48 h post-exercise to analyse sOB-R, leptin and insulin levels. At 24 h post-exercise, sOB-R and leptin concentrations at the 65% VO₂max were significantly different from those at the 25% VO₂max. Leptin levels at 48 h post-exercise were also significantly lower for the 65% VO₂max than for the 25% VO₂max (P < 0.01). In the 65% VO₂max session, the energy expenditure during exercise was significantly associated with leptin concentrations at 24 h and 48 h and sOB-R concentrations at 24 h post-exercise. However, no correlations were found between sOB-R and leptin at the three post-exercise time points. In conclusion, an acute bout of exercise with 920 kcal of output resulted in an increase in sOB-R levels at 24 h post-exercise. However, the changes in sOB-R levels due to an acute bout of exercise might not contribute to the delayed decrease observed for leptin.     

运动处方式教学对提高大学生体质预防运动性疾病的试验研究

关于运动对机体免疫能力的影响已有大量的研究,但处方式教学对提高大学生免疫功能、预防运动性疾病的影响尚不充分。实验表明,处方式教学在尊重教学规律的前提下根据学生不同体质状况采用不同运动种类,频度,强度和负荷,不仅运动素质提高而机体的免疫能力大幅增强,有效的预防了运动性疾病的产生,并且能有效的监控课堂训练,为激发教师和学生的积极性,科学的指导大学生进行自主锻炼,为高校大面积推广"运动处方式"教学提供了理论参考依据。     

Effects of Sit up Exercise Training on Adipose Cell Size and Adiposity

Abstract

The present experiment evaluated the effects of a 27-day sit up exercise training program on adipose cell size and adiposity. Fat biopsies were taken from the abdomen, subscapular, and gluteal sites by needle aspiration in 13 experimental and 6 control male subjects before and after a five days/week progressive training regimen. Day 1 consisted of 10 bouts of 10-sec exercise, 7 sit ups/bout, with 10-sec rest intervals; on day 27, 14 bouts of 30-sec exercise were performed, 24 sit ups/bout with 10-sec rest intervals. The total number of sit ups done was 5004. Fat cells were isolated using collagenase and photographed to determine cell diameter. Repeated measures ANOVA revealed significant decreases in cell diameter at the three biopsy sites (p<.01), but no significant differences in the rate of change (pre to post) in cell diameter between sites for the experimental and control groups (p>.05). Body weight, total body fat (underwater weighing), and fatfolds and girths remained unaltered. The results demonstrate that (1) the conventional sit up exercise does not preferentially reduce adipose cell size or subcutaneous fat thickness in the abdominal region to a greater extent compared to other adipose sites, and (2) significant changes in fat cell size may occur in the absence of changes in fatfolds, girths or total body composition.     

运动对大鼠红细胞免疫功能和粒细胞吞噬功能的影响

本文的研究目的在于探讨不同运动负荷的游泳训练对SD大鼠红细胞免疫功能和粒细胞吞噬功能的影响。本文采用C3b致敏孝母血凝法研究红细胞膜C3b受体活性以及红细胞免疫复合物的变化，采用PEG半定量法测定血清CIC的变化，以及对粒细胞吞噬功能的影响进行研究。结果发现：训练会对大鼠的红细胞免疫功能和粒细胞吞噬功能产生影响，其影响程度与运动负荷的变化有关，本研究提示：中等强度的运动对改善机体的红细胞免疫功能和增强粒细胞吞噬功能均有良好的作用。     

大负荷划船运动对血浆白介素- 8 水平的影响

细胞因子白介素-8(IL-8)与运动及机体的炎性反应有关。为观察IL-8在划船训练后的动态变化,选取有经验的划船运动员16人,随机平分为大负荷训练组(exercise group,E)及安静对照组(control group,C),训练前及训练后即刻、0.5 h1、h、10 h2、4 h测血浆IL-8及血乳酸(HL)浓度。结果发现:大负荷运动后血HL升高,但24 h内恢复;而血IL-8在运动后24 h内均显著升高(P<0.01)。提示在评定运动的负荷强度时,血HL反映骨骼肌能量代谢的变化;而IL-8作为与免疫有关的内分泌因子,能反映骨骼肌的内分泌及机体免疫功能的改变,将它们综合起来评定运动训练的负荷强度会更科学。