Abstract
This study examined the effect of three pre-exercise meals on various blood and cardiorespiratory variables during long-term and short-term submaximal endurance cycling. Eighteen endurance trained males between the ages of 18 and 35 years of age participated in this study examining the effects of a 200 isocaloric meal (in 300 mL) of glucose, whole milk, and an artificially flavored placebo following an overnight fast and a two-day diet high (>60%) in complex carbohydrates on three separate rides at 55% of maximal oxygen consumption for 120 minutes, followed by a 30 minute rest, and a short high intensity ride to exhaustion at 80% maximal oxygen consumption. Subjects were healthy and each paid $100 for their participation. Variables investigated were glucose, glycerol, free fatty acids, lactate, RER, HR, RPE, and time to exhaustion. Blood and cardiorespiratory variables were analyzed using a Repeated Measures ANOVA. Significant differences (p<0.05) were tested with a Bonferroni post hoc test. Only the means of the free fatty acids were significantly different between the rides (p<.007) with milk and glucola significantly blunting the rise in free fatty acids with exercise. However, all the variables changed over time. On the short ride there were no significant differences between any of the variables. While the differences were not significant, time to exhaustion for the carbohydrate meal was 18% longer than the whole milk meal and 20% longer than the placebo suggesting that a higher kilocaloric meal might have made a significant difference. These results demonstrate that, following an overnight fast, a 200 kilocaloric meal prior to endurance exercise will not make a difference in time to exhaustion whether it is a carbohydrate load or a mixed meal like whole milk. Additionally, a mixed meal of carbohydrate and protein will blunt the free fatty acid response during exercise similar to that of a carbohydrate only meal.
|
