The Ramadan fasting (RF) period is associated with changes in sleep habits and increased sleepiness, which may affect physical performance in athletes, and may induce metabolic, hormonal, and inflammatory disturbances. In 8 middle-distance athletes (25.0 +/- 1.3 years), a maximal aerobic velocity (MAV) test was performed 5 days before RF (day -5), and on days 7 and 21 of RF. The same days, saliva samples were collected to determine cortisol and testosterone concentrations before and after the MAV test. Blood samples were collected before RF (P1), at the end of RF (P2), and 1 week post RF (P3). Plasma levels of interleukin (IL)-6, a mediator of sleepiness and energy availability, were determined. We also evaluated changes in metabolic and hormonal parameters, mood state, and nutritional and sleep profiles. During RF, mean body mass and body fat did not statistically change. Compared with day -5, MAV values decreased at days 7 and 21 (p < 0.05, respectively), while testosterone/cortisol ratio values did not change significantly. Nocturnal sleep time and energy intake were lower at day 21 than before RF (day 0/P1) (p < 0.05). At the end of RF (day 31), the fatigue score on the Profile of Mood States questionnaire was increased (p < 0.001). For P2 vs. P1, IL-6 was increased (1.19 +/- 0.25 vs. 0.51 +/- 0.13 pg.mL-1; p < 0.05), melatonin levels were decreased (p < 0.05), and adrenalin and noradrenalin were increased (p < 0.01 and p < 0.001, respectively). At 7 days post RF, all parameters recovered to pre-RF values. In conclusion, RF is accompanied by significant metabolic, hormonal, and inflammatory changes. Sleep disturbances, energy deficiency, and fatigue during RF may decrease physical performance in Muslim athletes who maintain training. Reduction of work load and (or) daytime napping may represent adequate strategies to counteract RF effects for Muslim athletes.

This investigation examined the impact of a multistressor situation on salivary immunoglobulin A (sIgA) levels, and incidence of upper respiratory tract infection (URTI) during the French commando training (3 weeks of training followed by a 5-day combat course). For the URTI, the types of symptoms were classified according to the anatomical location of the infection. Saliva samples were collected (8 a.m.) from 21 males [21 (2) years] before entry into the commando training, the morning following the 3 weeks of training, after the 5-day combat course, and after 1 week of recovery. sIgA, protein and cortisol concentrations were measured. Symptoms of URTI were recorded during the study from health logs and medical examinations. After the 3 weeks of training, the sIgA concentration was not changed, although it was reduced after the 5-day course [from 120 (14) mg l(-1) to 71 (9) mg l(-1), P<0.01]. It returned to pre-training levels within a week of recovery. The incidence of URTI increased during the trial (chi(2)=53.48; P<0.01), but was not related to sIgA. Among the 30 episodes of URTI reported, there were 12 rhino-pharyngitis, 6 bronchitis, 5 tonsillitis, 4 sinusitis and 3 otitis. Cortisol levels were raised after the 3-week training (P<0.01), dropping below baseline after the combat course (P<0.01). Stressful situations have an adverse effect on mucosal immunity and incidence of URTI. However, the relationship between sIgA and illness remained unclear. The large proportion of rhino-pharyngitis indicated that the nasopharyngeal cavity is at a higher risk of infection.

This study was designed to determine whether the immune and hormonal systems were affected by a 5-day military course following 3 weeks of combat training in a population of 26 male soldiers (mean age, 21 +/- 2 years). The combination of continuous heavy physical activity and sleep deprivation led to energy deficiency. At the beginning of the training program and immediately after the combat course, saliva samples were assayed for secretory immunoglobulin A and plasma samples were assayed for interleukin-6, dehydroepiandrosterone sulfate, prolactin, catecholamines, glucocorticoids, and testosterone. Secretory immunoglobulin A was lower and circulating interleukin-6 was increased by the end of the course, which was attributed to sympathoadrenergic stimulation. Dehydroepiandrosterone sulfate, prolactin, and testosterone levels fell significantly. These results suggest that prolonged and repeated exercise such as that encountered in a military training program induces immune impairment via a decrease in mucosal immunity and a release of interleukin-6 into the circulation. The impaired secretion of dehydroepiandrosterone sulfate and prolactin, two immunomodulatory hormones, was thought to be a response to the chronic stressors. Lowered testosterone reflects a general decrease in steroid synthesis as a consequence of the physical and psychological strain.

Secretory immunoglobulin A (sIgA) is the major immunoglobulin of the mucosal immune system. Whereas the suppressive effect of heavy training on mucosal immunity is well documented, little is known regarding the influence of hypoxia exposure on sIgA during altitude training. This investigation examined the impact of an 18-day Living high-training low (LHTL) training camp on sIgA levels in 11 (six females and five males) elite cross-country skiers. Subjects from the control group (n=5) trained and lived at 1,200 m of altitude, whereas, subjects from the LHTL group (n=6) trained at 1,200 m, but lived at a simulated altitude of 2,500, 3,000 and 3,500 m (3x6-day, 11 h day(-1)) in hypoxic rooms. Saliva samples were collected before, after each 6-day phases and 2 weeks thereafter (POST). Salivary sIgA, protein and cortisol were measured. There was a downward trend in sIgA concentrations over the study, which reached significance in LHTL (P<0.01), but not in control (P=0.08). Salivary IgA concentrations were still lower baseline at POST (P<0.05). Protein concentration increased in LHTL (P<0.05) and was negatively correlated with sIgA concentration after the 3,000 and 3,500 m-phase and at POST (P<0.05 all). Cortisol concentrations were unchanged over the study and no relationship was found between cortisol and sIgA. In summary, data were strongly suggestive of a cumulative negative effect of physical exercise and hypoxia on sIgA levels during LHTL training. Two weeks of active recovery did not allow for proper sIgA recovery. The mechanism underlying this depression of sIgA could be mediated by neural factors.