Introduction Professional sleep associations recommend 7-9 h of sleep per night for young adults. Habitually sleeping less than 6 h per night has been shown to increase susceptibility to common cold in otherwise healthy, adult civilians. However, no investigations have examined the importance of sleep duration on upper respiratory tract infection (URTI) and loss of training days in military recruits. The purpose of this study was to describe self-reported sleep duration in a large cohort of military recruits and to assess the relationship between reported sleep duration and incidence of URTI's. We hypothesized that recruits who reported sleeping less than the recommended 7-9 h per night during training suffered a greater incidence of URTI and, as a consequence, lost more training days compared with recruits who met sleep recommendations. Materials and Methods Participants included 651 British Army recruits aged 22 ± 3 yr who completed 13 wk of basic military training (67% males, 33% females). Participants were members of 21 platoons (11 male, 10 female) who commenced training across four seasons (19% winter, 20% spring, 29% summer, and 32% autumn). At the start and completion of training, participants completed a questionnaire asking the typical time they went to sleep and awoke. Incidence of physician-diagnosed URTI and lost training days due to URTI were retrieved from medical records. Results Self-reported sleep duration decreased from before to during training (8.5 ± 1.6 vs. 7.0 ± 0.8 h; p < 0.01). Prior to training, 13% of participants reported sleeping less than the recommended 7 h sleep per night; however, this increased to 38% during training (X2 = 3.8; p = 0.05). Overall, 49 participants (8%) were diagnosed by a physician with at least one URTI and 3 participants (<1%) were diagnosed with two URTI's. After controlling for sex, body mass index, season of recruitment, smoking, and alcohol, participants who reported sleeping less than 6 h per night during training were four times more likely to be diagnosed with URTI compared with participants who slept 7-9 h per night in a logistic regression model (OR 4.4; 95% CI, 1.5-12.9, p < 0.01). On average, each URTI resulted in 2.9 ± 1.5 lost training days. Participants who were diagnosed with URTI had more overall lost training days for any illness compared with participants who did not report a URTI during basic military training (3.3 ± 1.9 vs. 0.4 ± 1.3; p < 0.01). Conclusion In a large population of British Army recruits, these findings show that more than one third of participants failed to meet sleep duration recommendations during training. Furthermore, those who reported sleeping less than 6 h per night were four times more likely to be diagnosed with an URTI and lost more training days due to URTI. Since sleep restriction is considered a necessary element of military training, future studies should examine interventions to reduce any negative effects on immunity and host defense.

The National Sleep Foundation recommends 7−9 hours of sleep per night for young adults. Habitually sleeping <6 hours per night has been shown to lower immunity and increase susceptibility to common cold following exposure to rhinovirus. However, no investigations have examined the importance of sleep duration on upper respiratory infection (URTI) and loss of training days in military recruits. PURPOSE: To identify if military recruits who typically sleep <6 hours per night during training suffer a greater incidence of URTI and, as a consequence, miss more training than recruits who meet sleep recommendations. METHODS: Participants included 651 British Army recruits aged 22 ± 3 years who completed 13 weeks of Phase 1 military training (67% males, 33% females). Recruits were members of 21 platoons (11 male, 10 female) who commenced training across the seasons (19% winter, 19% spring, 28% summer, and 33% autumn). At week 13, participants completed a questionnaire asking the normal time they went to sleep and awoke during training. Incidence of physician-diagnosed URTI and reduced or missed training days due to URTI were retrieved from medical records. RESULTS: Typical sleep duration during training was reported as 7.0 ± 0.8 hours per night with 5% of recruits reporting they normally slept <6 hours and 60% of recruits reporting 7-9 hours of sleep each night. In a logistic regression model, recruits who slept <6 hours per night were 4 times more likely to be diagnosed with URTI compared with recruits who slept 7−9 hours per night after controlling for sex, BMI, alcohol, smoking, and season of recruitment (OR 4.6; 95% CI, 1.7–12.8, P < 0.01). URTI’s diagnosed in recruits who slept <6 hours were spread across both sexes, 5 platoons and 3 seasons, showing sufficient heterogeneity. Overall, 49 recruits (8%) were diagnosed with at least one URTI, and 3 recruits (<1%) were diagnosed with two URTI’s. On average, each URTI resulted in 2.9 ± 1.5 reduced or missed training days. CONCLUSION: These findings show that military recruits who sleep <6 hours per night are more susceptible to URTI and miss more training due to URTI. Future studies should examine interventions to improve sleep hygiene in military training. Supported by MoD, UK.

PURPOSE Research has not convincingly demonstrated the utility of saliva secretory immunoglobulin-A (SIgA) as a biomarker of upper respiratory tract infection (URTI) risk, and disagreement exists about the influence of heavy exercise ("open-window theory") and dehydration on saliva SIgA. Prompted by the search for viable alternatives, we compared the utility of tear and saliva SIgA to predict URTI prospectively (study 1) and assessed the influence of exercise (study 2) and dehydration (study 3) using a repeated-measures crossover design. METHODS In study 1, 40 subjects were recruited during the common-cold season. Subjects provided tear and saliva samples weekly and recorded upper respiratory symptoms (URS) daily for 3 wk. Real-time PCR confirmed common-cold pathogens in 9 of 11 subjects reporting URS (82%). Predictive utility of tear and saliva SIgA was explored by comparing healthy samples with those collected during the week before URS. In study 2, 13 subjects performed a 2-h run at 65% V˙O2peak. In study 3, 13 subjects performed exercise heat stress to 3% body mass loss followed by overnight fluid restriction. RESULTS Tear SIgA concentration and secretion rate were 48% and 51% lower, respectively, during URTI and 34% and 46% lower the week before URS (P < 0.05), but saliva SIgA remained unchanged. The risk of URS the following week increased ninefold (95% confidence interval, 1.7-48) when the tear SIgA secretion rate was <5.5 μg·min(-1) and sixfold (95% confidence interval, 1.2-29) when the tear SIgA secretion rate decreased >30%. Tear SIgA secretion rate >5.5 μg·min(-1) or no decrease of >30% predicted subjects free of URS in >80% of cases. Tear SIgA concentration decreased after exercise (-57%, P < 0.05) in line with the "open-window theory" but was unaffected by dehydration. Saliva flow rate decreased and saliva SIgA concentration increased after exercise and during dehydration (P < 0.05). CONCLUSIONS Tear SIgA has utility as a noninvasive biomarker of mucosal immunity and common-cold risk.

PURPOSE:To examine the effects of intensity and duration of exercise stress on induction of in vivo immunity in humans using experimental contact hypersensitivity (CHS) with the novel antigen diphenylcyclopropenone (DPCP). METHODS:Sixty-four healthy males completed either 30 min running at 60% V˙O2peak (30MI), 30 min running at 80% V˙O2peak (30HI), 120 min running at 60% V˙O2peak (120MI), or seated rest (CON). Twenty min later, the subjects received a sensitizing dose of DPCP; and 4 wk later, the strength of immune reactivity was quantified by measuring the cutaneous responses to a low dose-series challenge with DPCP on the upper inner arm. Circulating epinephrine, norepinephrine and cortisol were measured before, after, and 1 h after exercise or CON. Next, to understand better whether the decrease in CHS response on 120MI was due to local inflammatory or T-cell-mediated processes, in a crossover design, 11 healthy males performed 120MI and CON, and cutaneous responses to a dose series of the irritant, croton oil (CO), were assessed on the upper inner arm. RESULTS:Immune induction by DPCP was impaired by 120MI (skinfold thickness -67% vs CON; P < 0.05). However, immune induction was unaffected by 30MI and 30HI despite elevated circulating catecholamines (30HI vs pre: P < 0.01) and greater circulating cortisol post 30HI (vs CON; P < 0.01). There was no effect of 120MI on skin irritant responses to CO. CONCLUSIONS:Prolonged moderate-intensity exercise, but not short-lasting high- or short-lasting moderate-intensity exercise, decreases the induction of in vivo immunity. No effect of prolonged moderate-intensity exercise on the skin's response to irritant challenge points toward a suppression of cell-mediated immunity in the observed decrease in CHS. Diphenylcyclopropenone provides an attractive tool to assess the effect of exercise on in vivo immunity.

Little is known about the influence of exercise on induction and elicitation phases of in vivo immunity in humans. We used experimental contact-hypersensitivity, a clinically relevant in vivo measure of T cell-mediated immunity, to investigate the effects of exercise on induction and elicitation phases of immune responses to a novel antigen. The effects of 2 h-moderate-intensity-exercise upon the induction (Study One) and elicitation of in vivo immune memory (Study Two) to diphenylcyclopropenone (DPCP) were examined. Study One: matched, healthy males were randomly-assigned to exercise (N=16) or control (N=16) and received a primary DPCP exposure (sensitization), 20 min after either 2 h running at 60% V O(2peak) (EX) or 2 h seated rest (CON). Four weeks later, participants received a low, dose-series DPCP challenge (elicitation) on their upper inner arm, which was read at 24 and 48 h as clinical score, oedema (skinfold thickness) and redness (erythema). Study Two: pilot; 13 healthy males were sensitized to DPCP. Elicitation challenges were repeated every 4 weeks until responses reached a reproducible plateau. Then, N=9 from the pilot study completed both EX and CON trials in a randomized order. Elicitation challenges were applied and evaluated as in Study One. Results demonstrate that exercise-induced stress significantly impairs both the induction (oedema -53% at 48 h; P<0.001) and elicitation (oedema -19% at 48 h; P<0.05) phases of the in vivo T-cell-mediated immune response. These findings demonstrate that prolonged moderate-intensity exercise impairs the induction and elicitation phases of in vivo T-cell-mediated immunity. Moreover, the induction component of new immune responses appears more sensitive to systemic-stress-induced modulation than the elicitation component.

Theories of leadership continue to capture the attention of the business community. Many books have been written on the subject and this paper seeks to analyze the eight most popular leadership books, based on library holdings and published since 2000, using the tools of worldview analysis. After describing worldview as an analytical tool, eight books are submitted to this analysis. By applying Athe ultimate questions of life≅ (Olthuis, 1985) to leadership texts, the ways in which these books shape and are shaped by the culture can be discerned. This provides the context for more meaningfully connecting Christian faith commitments to leadership theories. Worldview as an Analytical Tool Definition of worldview. The term worldview is used in a general sense to describe the situated perspective from which one views life. In a philosophical sense, worldview refers to systematic framework that guides the one=s encounter with the world. Rooted in the German concept of weltanschauung, worldview seeks to frame thought and action in terms of life=s ultimate questions. A rich body of worldview literature has emerged that defines worldview as a Aset of beliefs,≅ a Amodel,≅ a Aframework,≅ a ≅picture,≅ and a Asystem≅ that helps us make sense of the world and guides our action in the world (Ward, 2003). These definitions highlight the dual functions of worldview. Worldview is presuppositional. It represents the sense-making process, often occurring sub-consciously, that orients us to the world around us. For example, a person may be said to see the world as a "glass, half-empty" or a "glass, half-full." This orientation to world is considered part of that individual's sensibility, often displayed in unintentional expressions of pessimism or optimism. In this function, worldview serves to explain behavior, helping make sense of the motivations for an individual or group's engagement with the world. Worldview is also propositional. It serves as the basis for developing a cohesive engagement with the world. In this function, worldview can be made explicit. For example, the just war theory is an attempt by many in the Christian church to explicate the rationale for a response to a specific conflict. Analysis and debate are invited to insure that the Church's response is consistent with her fundamental convictions. In this function, worldview serves to orient behavior, helping guide its adherents to "respond prophetically and creatively to each new situation" (Walsh, 2002). Peter Heslam (2003) highlights how these two functions intersect for the Christian. Worldviews are not the end-point of our quest for insight, but our place of departure. This is because they are rooted in the most basic aspect of human existence - faith. This means that their tenets are not argued to, but from. It also means that having a worldview is not the issue. We all have one, simply by being humans made in the image of God. The question is the extent to which we are willing to allow our Christian