Author(s): WANG, H.S., HUANG, I.H., LI, M.S., LI, Y.H., Institution: NATIONAL TAIWAN NORMAL UNIVERSITY, Country: TAIWAN, Abstract-ID: 1688

INTRODUCTION:
Optimal strategies for supplementation during the short-term recovery period following exercise play a critical role in enhancing subsequent exercise performance. With the substantial depletion of muscle glycogen after exercise, supplementing carbohydrates along with caffeine can aid in the resynthesis of muscle glycogen. However, further investigation is required to determine whether the benefits of this glycogen synthesis translate into improved subsequent endurance exercise performance. Purpose: To investigate the impact of carbohydrate supplementation with caffeine during the post-exercise recovery period on subsequent endurance exercise performance.
METHODS:
Twelve healthy, physically active men (26.9 ± 3.1 yrs) with regular exercise habits were recruited. They participated in two running treadmill sessions, separated by one week, consisting of 75 minutes of running at 70% V̇O2max at a fixed speed. After a 4-hour recovery period, they underwent an endurance exercise performance test (5-km time trial). Two experimental trials were administered during the recovery period in a randomized, double-blind, counterbalanced order: 1) Caffeine + Carbohydrate (CAF+CHO) trial, where participants consumed 4.8 g of carbohydrate per kg of body weight and 6 mg of caffeine per kg of body weight; 2) Carbohydrate (CHO) trial, where participants consumed 4.8 g of carbohydrate per kg of body weight and a placebo. During the recovery period, respiratory gas data were collected, and abdominal discomfort (AD) was recorded. Blood samples were also collected at baseline, during the recovery period, and after the endurance exercise performance test.
RESULTS:
1) The 5-km time trial run performance was significantly better in the Caffeine + Carbohydrate (CAF+CHO) trial compared to the Carbohydrate (CHO) trial (1475 ± 215 sec vs. 1574 ± 276 sec, p < 0.05); however, heart rate and RPE (Rate of Perceived Exertion) showed no significant interaction between trial and time factors, and the main trial effects were not significant. 2) Blood glucose, lactate, insulin, free fatty acids, glycerol, carbohydrate oxidation rate, and lipid oxidation rate showed no significant interaction between trial and time factors, and the main trial effects were not significant. 3) The abdominal discomfort during the recovery period showed no interaction between trial and time factors, with only the main time factor being significantly higher at the 3rd hour than at previous time points, and significantly higher at the 4th hour compared to the 3rd hour (p < 0.001).
CONCLUSION:
Following 75 minutes of endurance exercise at 70% VO2max, consuming carbohydrates (4.8 g/kg) in combination with caffeine (6 mg/kg) during the recovery period can enhance subsequent performance in the 5-kilometer time trial run. This suggests that carbohydrate supplementation with caffeine can be an effective post-exercise recovery strategy.