Cardiovascular and Metabolic Responses During 30 Minutes of Treadmill Exercise Shortly After Consuming a Small, High-Carbohydrate Meal

Fourteen male endurance runners (VO₂peak = 64.8±8.7 ml x kg^-1 x min^-1) participated in this study to determine the cardiovascular and metabolic responses during 30 minutes of treadmill running at a moderate intensity soon after consuming a small, high-carbohydrate meal (CHO-M). In randomized order on separate days, subjects either consumed the CHO-M (2088 kJ; 77 % carbohydrate) 15 minutes prior to running or they fasted (FAST). Data were collected for 5 minutes beginning at 5, 15, and 25 minutes of the 30-minute run. Heart irate (HR) was determined, a metabolic measurement cart was used to determine VO₂ and respiratory exchange ratio (RER), and the CO₂ re-breathing procedure (Collier plateau method) was used to determine cardiac output (Q). Statistical analyses indicated that the CHO-M did not affect HR, stroke volume, Q₁, VO₂, or RER compared to FAST. However, all grouped CHO-M and FAST variables, except VO₂, changed significantly across the 30-minute exercise session. These data suggest that a small, high-carbohydrate meal does not alter cardiovascular and metabolic function during moderate-intensity exercise in endurance-trained subjects.

Key words

Postprandial - cardiac output - oxygen consumption - heart rate - stroke volume - carbon dioxide rebreathing