Innate immune responses to a single session of sprint interval training.

Sprint interval training (SIT) is a potent stimulus for physiological and metabolic adaptations comparable with those induced by traditional "aerobic" endurance training. There has been a great deal of recent research on SIT, which may lead to increased use of this type of training. The purpose of the present study was to determine the acute effects of SIT on aspects of innate immunity not previously researched in this context. Nine males completed 1 SIT and 1 resting control trial in a crossover design. Blood and saliva samples were obtained at pre-, post-, and 30 min postexercise to measure blood neutrophil oxidative burst activity (OBA) in addition to saliva secretary IgA (s-IgA) and lysozyme. SIT induced a significant depression of neutrophil fMLP-stimulated OBA (-30% for the 30-min postexercise time point, p  0.05). The main novel finding of the present study is that a single session of SIT causes significant exercise-induced immunodepression of some neutrophil functions but mucosal immunity was not depressed

Linking Distributive and Procedural Justice to Employee Engagement Through Social Exchange: A Field Study in India

Research linking justice perceptions to employee outcomes has referred to social exchange as its central theoretical premise. We tested a conceptual model linking distributive and procedural justice to employee engagement through social exchange mediators, namely, perceived organizational support and psychological contract, among 238 managers and executives from manufacturing and service sector firms in India. Findings suggest that perceived organizational support mediated the relationship between distributive justice and employee engagement, and both perceived organizational support and psychological contract mediated the relationship between procedural justice and employee engagement. Theoretical and practical implications with respect to organizational functions are discussed

Current challenges and future expectations in exercise immunology: Back to the future

The immune system response to exercise is multifaceted, depending on the nature of exercise. The motivation behind recent research on the immune response to exercise comes from four basic directions: (i) keeping competitive athletes healthy, based on the perception that athletes are susceptible to infectious illness during intense training and competition; (ii) community interest in health promotion, based on the beneficial effect of exercise in lessening the risk of other lifestyle-associated diseases such as heart disease; (iii) use of exercise as adjunct therapy to improve patient functional capacity in certain diseases such as acquired immune deficiency syndrome (AIDS) and cancer; and (iv) work in the field of psychoneuroimmunology showing significant interaction between the neuroendocrine and immune systems, and the role of lifestyle factors in modulating immune function. Future work in exercise immunology will focus on topics such as: identifying the role of neuroendocrine factors in regulating the immune response to exercise; understanding the effects and appropriate type of moderate exercise in patients with diseases which involve the immune system; and possible long-term role of regular exercise in preventing diseases such as cancer, or the decline in immune function which accompanies the aging process

The effect of endurance training on lipoprotein(a) [Lp(a)] levels in middle-aged males

Serum lipoprotein(a) [Lp(a)] levels were measured before and after a 12- wk program of moderate-intensity endurance training. The training program consisted of walking and/or jogging, at least three sessions·wk of at least 30 min duration, at an intensity producing 60-85% HR(max) reserve. Twenty-eight previously sedentary middle-aged Caucasian males matched for age, body mass, and body mass index (BMI) were randomly allocated to either an exercise (N = 17, mean age ± SEM = 51.57 ± 1.25 yr) or a control (N = 11, mean age ± SEM = 50.0 ± 1.15 yr) group. Pre- and post-training median Lp(a) levels, measured by immunoturbidimetric analysis, were not significantly different in either the exercise (pre 13.0, post 15.0 mg·dl ) or the control subjects (pre 14.0, post 12.0 mg·dl)(P > 0.05). Kendall Rank correlation analysis revealed no significant relationship between the level of Lp(a) and any other variable in either group before or after training. In the exercisers, a significant increase (P < 0.05) was recorded in the estimated mean V̇O(2max) (pre 33.39 ± 1.70, post 37.7 ± 1.75 ml·kg·min). These data indicate that the level of Lp(a) was not influenced by a 12-wk program of moderate intensity endurance training, and are consistent with previous reports suggesting that Lp(a) level is not altered by lifestyle factors

The validation of backward extrapolation of submaximal oxygen consumption from the oxygen recovery curve

The purpose of this study was to determine the validity and practicality of exponential vs linear backward extrapolation of the O2 recovery curve for prediction of exercise oxygen consumption (VO2). Eight men and women, age 20.1, 0.9 years, body mass 66.0, 2.5 kg (mean, SEM), completed seven bouts of cycle ergometer exercise at submaximal power outputs ranging from 50 to 175 W. Respiratory gases were collected from each subject during exercise and recovery. The monoexponential extrapolation of five recovery samples (r2=0.85) and linear extrapolation of one recovery sample taken during the first 20-s of recovery (r2=0.83) accounted for similar amounts of variance in predicting exercise VO2. The linear regression equation was the most practical predictor, as only one recovery gas sample was necessary and it did not require the complicated mathematical techniques used in exponential regression

Decreased salivary immunoglobulins after intense interval exercise before and after training

Endurance athletes have been shown to suffer a high incidence of upper respiratory tract infection (URTI). Previous studies have shown that concentration and flow rate of secretory immunoglobulin A (IgA), the major effector of host resistance to URTI, decrease after intense endurance exercise. The purpose of this study was to determine whether salivary IgA concentration and flow rate decrease after brief intense interval exercise, and whether the response to exercise changes with training. Twelve male subjects performed five 60-s bouts of supramaximal interval exercise at 0.075 g.kg-1 body mass on a cycle ergometer; each bout was separated by 5-min rest. Subjects then trained for 8 wk by performing the same interval exercise protocol three times per week. Timed, whole unstimulated saliva samples were obtained before and after the interval exercise protocol, before and after training. Salivary IgA, IgG, and IgM concentrations were measured by ELISA and flow rates calculated. IgA and IgM concentrations relative to total protein decreased after each exercise session; IgG concentration relative to total protein did not change after exercise. IgA, IgM, and IgG flow rates decreased 50-65% after interval exercise. There was no effect of training on any immune parameter measured, although total work performed in the five 60-s bouts increased after training. These data show that the output of salivary IgA and IgM decrease after brief supramaximal interval exercise. and that the decreased output is due, at least partially, to the decrease in saliva flow. In addition, there appears to be a specific effect of intense exercise on IgA concentration greater than that due to decreased saliva flow alone. These data suggest that decreases in secretory IgA output after repeated bouts of supramaximal exercise may be one mechanism contributing to the high incidence of upper respiratory tract infection among athletes

The effects of stress management on symptoms of upper respiratory tract infection, secretory immunoglobulin A, and mood in young adults

To investigate the efficacy of a stress management programme on symptoms of colds and influenza in 27 university students before and after the examination period. The incidence of symptoms, levels of negative affect, and secretion rate of secretory immunoglobulin A (sIgA) were recorded for 5 weeks before treatment, for the 4 weeks of treatment, and for 8 weeks after treatment in treated subjects and in 25 others who did not participate in stress management. Symptoms decreased in treated subjects but not in controls during and after the examination period. Although sIgA secretion rate increased significantly after individual sessions of relaxation, resting secretion rate of sIgA did not increase over the course of the study. Negative affect decreased after examinations in both groups, but was not affected by treatment. Stress management reduced days of illness independently of negative affect and sIgA secretion rate. Although the component of treatment responsible for this effect has yet to be identified, psychological interventions may have a role in reducing symptoms of upper respiratory tract infection