Carbohydrate Beverage Ingestion and Neutrophil Degranulation Responses Following Cycling to Fatigue at 75 % V˙O₂ max

Abstract

Carbohydrate (CHO) beverage ingestion appears to influence neutrophil functional responses to prolonged exercise of a fixed duration. The aim of this randomised study was to examine the effect of CHO (5% w/v) beverage ingestion on lipopolysaccharide (LPS)-stimulated neutrophil degranulation responses in nine recreationally active males who cycled at 75% VO2 max until fatigue. On two separate occasions, subjects ingested either placebo (PLA) or CHO beverages before and at 15 min intervals during the exercise. Subjects exercised for 31% longer on the CHO trial compared with the PLA trial (P < 0.05). At fatigue plasma glucose concentration was significantly lower on the PLA trial compared with the CHO trial (P < 0.05). Plasma cortisol concentrations had increased similarly on both trials at this time. A marked neutrophilia was evident at fatigue and throughout the 4 h recovery period, the magnitude of which was similar on both trials. At fatigue LPS-stimulated elastase release per neutrophil had fallen similarly on both trials compared with pre-exercise values (47% and 50% on the PLA and CHO trials, respectively). In conclusion, our results suggest that CHO beverage ingestion has negligible influence on the hormonal, circulating neutrophil and LPS-stimulated neutrophil degranulation responses when exercise is performed to fatigue.

The Effects of Sports Drink Osmolality on Fluid Intake and Immunoendocrine Responses to Cycling in Hot Conditions

“…This discrepancy may relate to the lower intensity and duration of exercise in the present study compared with other studies, which have typically involved more intense (i.e., $70% VO2max) and/or prolonged exercise (i.e., $2 h) (1-3). In the present study, plasma glucose concentration at the end of exercise in the isotonic and hypotonic drink trials was similar to or higher than other studies on the effects of carbohydrate supplementation on immunoendocrine responses to exercise (3)(4)(5)(21)(22)(23)(24). Plasma glucose concentration at the end of exercise in the water trial in the present study was also higher than in some other studies (3,23,24).…”

“…Some studies report that carbohydrate prevents a decline in neutrophil elastase release (3) and oxidative burst activity (25), whereas other studies demonstrate no effect of carbohydrate (2,(22)(23)(24)26). These discrepant findings are likely due to variation in various factors including exercise protocols, the training status of subjects, timing of blood samples and assays of neutrophil function (27,28).…”

Carbohydrate Gel Ingestion and Immunoendocrine Responses to Cycling in Temperate and Hot Conditions

“…One study (Bishop, Blannin, Walsh, & Gleeson, 2001) reported that the effects of carbohydrate on immunoendocrine responses are diminished during cycling to fatigue. This effect is a result of the fact that carbohydrate prolongs time to fatigue, resulting in greater immune changes in response to the longer exercise duration.…”

The athlete’s diet: nutritional goals and dietary strategies

“…This strategy has the effect of minimising any rise in plasma levels of stress hormones (cortisol, catecholamines and growth hormone) known to have a negative effect on immunity, and is likely to be the most successful nutritional strategy (Nieman & Pedersen, 1999). If exercise is continued to the point of exhaustion, however, providing carbohydrate during exercise can extend the exercise time, but has little effect on the hormonal and immune cell responses (Bishop et al 2001). This last finding is interesting and underlines the physiological mechanisms involved, but it is not clear whether there are practical implications for the athlete engaged in intensive training.…”