Mucosal immunity and illness incidence in elite rugby union players across a season.

PURPOSE: To examine the relationship between upper respiratory illness (URI) incidence with changes in mucosal immunity (saliva immunoglobulin A (s-IgA) and saliva lysozyme (s-Lys)) and training load (TL) in a squad of elite rugby union players. METHODS: Timed resting morning saliva samples were taken from players (n = 31) at preselected time points for 11 months. Weekly illness rates and TL were assessed using a Web-based diary and from medical/coaching staff reports. RESULTS: No significant correlation was found between absolute s-IgA or s-Lys concentrations and URI incidence. Peaks in URI (December and March) were preceded by periods of increased training intensity and reduced game activity. In 23% of all URI episodes, players reported that presence of an illness either reduced activity (14.4%) or felt the need to go to bed (8.6%). When s-IgA concentration was expressed relative to that when in a URI-free state, a 15% reduction (P = 0.08) was observed in individuals who had present URI symptoms. Decreases in absolute s-IgA (December) and s-Lys (November and February) concentrations were associated with a corresponding increase in saliva cortisol (P < 0.05). Lower s-IgA (P < 0.05) and s-Lys concentrations were consistently observed in backs than forwards, whereas URI incidence also differed for player position (3.4 forwards vs 4.3 backs). CONCLUSIONS: Regular monitoring of s-IgA and s-Lys may be useful in the assessment of exercise stress and URI risk status in elite team sport athletes. A combination of alterations in training intensity and seasonal influence is a likely contributor to observed peaks in URI incidence. It is probable that stress-induced increases in cortisol release contribute to reductions in mucosal immunity, which, when lowered, predispose rugby players to increased risk of illness.

Time course of changes in immuneoendocrine markers following an international rugby game.

Intense exercise is known to cause temporary impairments in immune function. Few studies, however, have investigated the effects of intense competitive exercise on immunoendocrine variables in elite team sport athletes. The aim of this study was to evaluate the time course of changes in selected immunoendocrine and inflammatory markers following an international rugby union game. Blood samples were taken from players (n = 10) on camp entry, the morning of the game (pre), immediately after (post) and 14 and 38 h into a passive recovery period. Players lost 1.4 +/- 0.2 kg of body mass during the game (ambient conditions, 11 degrees C, 45% RH). An acute phase inflammatory response was observed as reflected through immediate increases in serum cortisol and IL-6 (post) followed by delayed increases in serum creatine kinase (CK; 14 h) activity and C-reactive protein (CRP; 38 h); P < 0.05. Decreases in the number of circulating T lympocytes, NK cells and bacteria-stimulated neutrophil degranulation were also observed post-exercise (P < 0.05), indicative of decreased host immune protection. Following a large decrease in serum testosterone to cortisol (T/C) ratio immediately post and 14 h after exercise, T/C values then increased above those observed at camp entry 38 h into recovery (P < 0.05). This rebound anabolic stimulus may represent a physiological requirement for recovery following intense tissue damage resulting from game collisions. The findings also suggest that a game of international rugby elicits disturbances in host immunity, which last up 38 h into the recovery period.

Illness monitoring in team sports using a Web-based training diary.

OBJECTIVE: Use of Web-based data recording systems has received little attention in sport. An "online" training diary could provide a valuable alternative to pen-paper methods in the regular assessment of physical activity and illness occurrence in athletes. The objective of this study was to design and implement a user-friendly and efficient system to monitor incidences of illness in team sport athletes. DESIGN: Prospective monitoring study over a 48-week rugby season. Players were asked to register presence/absence of weekly illness symptoms with medical staff and also use an online training diary. Submitted self-reported diary illness data were compared with illness complaint data recorded by medical staff. Diary response rates were calculated from the number of completed diary entries against the number of available/required entries over the season. SETTING: Web-based training diary. PARTICIPANTS: Thirty professional rugby union players. INTERVENTION: Comparison of gastrointestinal and upper respiratory illnesses (URIs) reported by players using an online diary and to medical staff. MAIN OUTCOME MEASURES: Incidences of URIs. RESULTS: The diary response rate in the reporting of weekly illnesses was 79% over the study period. Discrepancy existed between the number of self-reported URIs by players using the diary (118 URI incidences) compared with those reported to medical staff (23 URI incidences). Totaling all URI episodes (those self-reported + those registered by medical staff) revealed that players reported just 19% of URI episodes to medical staff. CONCLUSIONS: Players tend to underreport incidences of banal infections. Closer monitoring of self-reported illnesses using a similar system in the present study may provide a better alternative to previous methods in nonclinical illness assessment.

AMPK inactivation in mononuclear cells: a potential intracellular mechanism for exercise-induced immunosuppression.

There is much evidence that prolonged intense exercise suppresses the immune system. However, the intracellular biochemical mechanisms linking exercise and immunosuppression remain obscure. The purpose of this study was to investigate the hypothesis that exercise-induced inactivation of 5'AMP-activated protein kinase (AMPK) disrupts individual immune cell function, and thus may be linked to exercise-induced immunosuppression. To confirm AMPK's role in immune cells, AMPK activity was assessed in cultured monocytic Mono Mac 6 (MM6) cells. The effects of single bouts of intense exercise (45 min cycling; 70% VO2 max) on several immune parameters including mononuclear cell AMPK phosphorylation were investigated in 10 male volunteers. In vitro, the mitochondrial ATP synthase inhibitor oligomycin brought about transient decreases in cellular [ATP] (0.41+/-0.04 pmol/cell to 0.31+/-0.02 pmol/cell), and activation of AMPKalpha1 (170.7%+/-31.2% basal) and the glycolytic enzyme inducible phosphofructokinase 2 (iPFK-2) (225.0%+/-46.1% basal), with the latter effects coinciding with recovery from ATP depletion. In contrast, exercise-induced transient (approximately 1 h) decreases in AMPKalpha1 phosphorylation (64.4%+/-17.6% basal). This AMPK inactivation coincided with comparable transient decreases in other immune parameters (salivary IgA levels, serum cytokine levels, monocyte CD36 expression). Although the brief exercise bout employed here is not sufficient to cause full-fledged immunosuppression, exercise-induced transient decreases in mononuclear cell AMPK activation (as seen in this study) may cause energy depletion within individual immune cells, and therefore have an impact upon their ability to carry out their functions. Thus, we suggest that prolonged, repeated, high-intensity exercise that leads to clinically relevant immunosuppression may do so via AMPK inactivation within immune cells.