Effect of Caffeine Ingestion of Long Distance Runner on Energy Substrate of Blood

Journal of Exercise Nutrition & Biochemistry 1998;2(1):45-56.

Abstract

The purpose of this study is to describe the effects of caffeine ingestion on the metabolic responses during submaximal exercise. Ten male of long distance runners aged 19-22yrs were sampled for this study. No subjects had any remarkable medical history and none were taking medications. According to the ingestion of dehydrated caffeine(6㎎/㎏), they were classified into two groups ; caffeine group(CA) and placebo group(PA). A randomized, double-blind, and crossover protocol was employed using for both CA and PA. Subjects underwent a submaximal bicycle ergometer. Blood was drawn intravenously prior to 60 minutes, at rest, at 30 minutes, and 45 minutes of exercise, and recovery period. Plasma concentrations of glucose, free fatty acid and lactate were obtained using enzymatic method. The followings were obtained by the tests and analyses ; 1) Blood glucose (BG) after 45 minutes of exercise was significantly decreased in CA group of 79.0±12.4 ㎎/100㎖ compared with PA group of 93.7±10.4 ㎎/100㎎ (p<.05). 2) Free fatty acid(FFA) after 30 minutes of exercise was significantly increased in CA group of 680.7±90.2 μEq/ℓ compared with PA group of 380.9±120.4 μEq/ℓ(p<.05). The recovery of FFA of recovery was significantly different between CA group of 980.8 ±100.3 μEq/ℓand PA group of 610.7±80.6 μEq/ℓ(p<.05). After exercise, FFA was significantly higher in CA group than in PA group (p<.05, p<.01). 3) There was no significant difference in blood lactate between the two. After exercise, BL was higher than resting both CA group(2530±870 μEq/ℓ, p<.05) and PA group(2120±790 μEq/ℓ, p<.05) respectively.