EXERCISE EFFECTS OF CAFFEINE ON BLOOD SUGARS IN TEENAGERS WITH INSULIN DEPENDENT DIABETES MELLITUS (IDDM) 1436

Abstract

Low blood sugars occur frequently during exercise in young patients with IDDM. The purpose of this study was to determine the effect of caffeine in the attenuation of the rate of blood sugar decline during exercise in teenagers with IDDM. Subjects were assumed to be in good diabetic control based on Hemoglobin A1c (HbA1c) values (≤9.0%). Four male and four female subjects (X±S.D.) HT(cm)= 163.5±7.8, WT(kg)= 57.3±11.5, AGE(yrs)= 15±2 completed four exercise sessions. Each subject completed two maximal tests on a Quinton Corival 400 electronically braked cycle ergometer using a ramp type protocol. Each test was one week apart with the first test serving as a familiarization trial. Following maximal cycle exercise testing (MCET), patients underwent two submaximal 45 minute rides (SMR) with a 5 min. warm-up and 5 min. cool-down. Workloads during SMR were maintained at 70-75% of peak heart rate achieved during MCET. Workloads were adjusted during SMR to maintain the desired heart rate intensity. One hour prior to each SMR, subjects ingested a placebo or caffeinated drink (5mg/kg) in a double blind randomized crossover design. Blood sugars were taken at the onset of exercise and repeated every 15 min. during SMR and a 30 min. post-test observation period. Data were analyzed using the random intercepts mixed model. Test results showed the rate of decline of blood sugar in the placebo trial to be 1.75 mg/dl/min. while the rate of decline in the caffeine trial was 0.95 mg/dl/min. These data show that caffeine significantly (p<0.0001) slowed the rate of blood sugar decline by 47% compared to the placebo trial. These results suggest that caffeine ingestion one hour prior to moderate intensity aerobic exercise may be beneficial to young patients with IDDM.