Postprandial glucose and insulin responses to a postexercise grain meal

Many studies have examined the effect of pre-exercise feeding on glucose and insulin responses of horses. The objective of this study was to determine whether exercise performed one hour prior to a meal would attenuate the glucose and insulin responses to a meal. Data collected from 8 mature geldings in a 2 period crossover design experiment were used to determine the postprandial glucose and insulin responses to a meal of oats offered 1 h postexercise. During each period, 4 horses received a test meal following a 14 h fast (NoEx) or a 14 h fast and exercise bout (PostEx) that consisted of 48 min walking and trotting. Blood samples were collected before and at 30 min intervals for 5 h after the meal was offered. Glucose and insulin concentrations were similar between treatments at all time points (P>0.15). Postprandial glucose and insulin concentrations increased at similar rates in both groups from 0 to 90 min. Peak glucose and insulin concentrations and area under the response curves were similar between treatment groups. Glucose:insulin was not different between treatment groups at any time point before or after the meal (P>0.17). Overall, the 48 min of light work performed 1 h before a meal did not affect glucose or insulin responses to the meal. A one hour interval after mild exercise appears to be sufficient to allow normal glucose metabolism of a grain meal.