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This randomized, double-blind, placebo-controlled study was designed to determine the influence of 6% carbohydrate (C) vs. placebo (P) beverage ingestion on cytokine responses (5 total samples over 9 h) to 2.5 h of high-intensity running (76.7 +/- 0.4% maximal O2 uptake) by 30 experienced marathon runners. For interleukin-6 (IL-6), a difference in the pattern of change between groups was found, highlighted by a greater increase in P vs. C immediately postrun (753 vs. 421%) and 1.5 h postrun (193 vs. 86%) [F(4,112) = 3.77, P = 0.006]. For interleukin-1-receptor antagonist (IL-1ra), a difference in the pattern of change between groups was found, highlighted by a greater increase in P vs. C 1.5 h postrun (231 vs. 72%) [F(2,50) = 6.38, P = 0.003]. No significant interaction effects were seen for bioactive IL-6 or IL-1 beta. The immediate postrun plasma glucose concentrations correlated negatively with those of plasma cortisol (r = -0.67, P < 0.001); postrun plasma cortisol (r = 0.70, P < 0.001) and IL-6 levels (r = 0.54, P = 0.003) correlated positively with levels of IL-1ra. Taken together, the data indicate that carbohydrate ingestion attenuates cytokine levels in the inflammatory cascade in response to heavy exertion.

A randomly controlled 15-wk exercise training (ET) study (five 45-min sessions/wk, brisk walking at 60% heart rate reserve) with a group of 36 mildly obese, sedentary women was conducted to investigate the relationship between improvement in cardiorespiratory fitness, changes in natural killer (NK) cell number and activity, and acute upper respiratory tract infection (URI) symptomatology. The study was conducted using a 2 (exercise and nonexercise groups) x 3 (baseline, 6-, and 15-wk testing sessions) factorial design, with data analyzed using repeated measures ANOVA. No significant change in NK cell number occurred as a result of ET as measured by the CD16 and Leu-19 monoclonal antibodies. ET did have a significant effect on NK cell activity (E:T 50:1) especially during the initial 6-wk period [F(2.68) = 12.34, p less than 0.001]. Using data from daily logs kept by each subject, the exercise group was found to have significantly fewer URI symptom days/incident than the nonexercise group (3.6 +/- 0.7 vs 7.0 +/- 1.4 days, respectively, p = 0.049). Improvement in cardiorespiratory fitness was correlated significantly with a reduction in URI symptom days/incident (r = 0.37, p = 0.025) and a change in NK cell activity from baseline to six but not 15 wks (r = 0.35, p = 0.036). In summary, moderate ET is associated with elevated NK cell activity after six but not 15 weeks, and reduced URI symptomatology in comparison to a randomized, sedentary control group.

The influence of exercise mode and 6% carbohydrate (C) vs. placebo (P) beverage ingestion on granulocyte and monocyte phagocytosis and oxidative burst activity (GMPOB) after prolonged and intensive exertion was measured in 10 triathletes. The triathletes acted as their own controls and ran or cycled for 2.5 h at approximately 75% maximal O2 uptake, ingesting C or P (4 total sessions, random order, with beverages administered in double-blind fashion). During the 2. 5-h exercise bouts, C or P (4 ml/kg) was ingested every 15 min. Five blood samples were collected (15 min before exercise, immediately after exercise, and 1.5, 3, and 6 h after exercise). The pattern of change over time for GMPOB was significantly different between C and P conditions (P

Sixteen female breast cancer patients who had been diagnosed (3.0 +/- 1.2 years previous to the study) and undergone surgery, chemotherapy, and/or radiation treatment were randomly assigned to exercise and nonexercise groups. Pre- and post-study measurements were taken for aerobic performance, leg strength, and concentrations of circulating lymphocyte subsets and natural killer cell cytotoxic activity (NKCA). Exercise training consisted of 60 minutes of supervised weight training and aerobic activity three times each week for eight weeks. Although subjects in the exercise groups demonstrated some modest improvement in the various aerobic and strength tests, NKCA and concentrations of circulating T and NK cells were not significantly altered relative to the nonexercise group. This study suggests that moderate exercise over an eight-week period has no significant effect on the function of in vitro natural killer cells in breast cancer patients.

The influence of carbohydrate (1 l/h of a 6 % carbohydrate beverage), gender, and age on salivary IgA (sIgA) changes and incidence of upper respiratory tract infection (URTI) was studied in 98 runners following two competitive marathon races. The pattern of change in sIgA concentration differed significantly between carbohydrate (C) (N = 48) and placebo (P) (N = 50) groups, with higher post-race values measured in P. However, when this was adjusted for saliva protein concentration and saliva secretion rate, no difference between groups was measured. For all subjects combined, sIgA concentration, saliva IgA: protein ratio (spIgA), and sIgA secretion rates fell significantly (21 %, 31 %, and 25 %, respectively) below pre-race levels by 1,5-h post-race (p < 0.001). The pattern of change in all saliva measures did not differ significantly between the 12 women and 86 men in this study, and between the 23 older (> or =50 yr) and 75 younger (< 50 yr) subjects. Ninety-three subjects returned health/sickness logs, and of these, 16 (17 %) reported developing URTI during the 15-d period following the race event. The 1.5-h post-race spIgA concentration, but not sIgA concentration or secretion rate, was lower in runners reporting URTI compared to those who did not (254 +/- 30 and 388 +/- 26 microg*g(-1), respectively, p = 0.002), and this was negatively correlated with the post-race plasma cortisol concentration (r = -0.36, p < 0.001). Of the 16 runners, six were in the C group and 10 in the P group (Chi square = 1.11, p = 0.293). In conclusion, the output of sIgA decreased in runners following a competitive marathon, and this was not influenced by carbohydrate ingestion, age, or gender.

The effect of 45 min of high- (80% VO2max) versus moderate- (50% VO2max) intensity treadmill exercise on circulating leukocyte and lymphocyte subpopulations, catecholamine and cortisol concentrations, and the mitogen-stimulated lymphocyte proliferative response was investigated in 10 well-conditioned (mean VO2max 66.0 +/- 1.9 ml/kg/min), young males (mean age 22.1 +/- 1.3 yrs). Blood samples were taken before and immediately after exercise, with three more samples taken during 3.5 h of recovery. Treatment order on the treadmill (graded walking at 7.3 +/- 0.1 km/h, 6.5 +/- 0.6% grade, versus level running at 16.1 +/- 0.3 km/h) was counterbalanced, with subjects acting as their own controls and results analyzed using a 2 x 5 repeated measures ANOVA. The concanavalin A- (Con A) stimulated lymphocyte proliferative response was decreased at 1 h and 2 h post-exercise relative to baseline levels following both exercise-intensity conditions. However, when adjusted on a per-T cell (CD3+) basis to account for the change in number of T cells in the in vivo assay, only the high-intensity exercise condition was associated with a 1-h post-exercise decrease (21%, p = 0.05) in the proliferative response relative to baseline. Exercise at 80% versus 50% VO2max resulted in significantly greater increases in cortisol and epinephrine concentrations, providing a physiological rationale for the immediate-post-exercise lymphocytosis, 1- to 3.5-h lymphocytopenia, and the decrease in Con A-stimulated lymphocyte proliferative response (per CD3+ cell) that occurred in greater measure following high-intensity exercise.