EFFECTS OF VARIED DOSES OF COFFEE-CAFFEINE ON RESTING CARDIOVASCULAR SYSTEM OF HEALTHY BLACK AFRICAN ADULTS

Abstract

BACKGROUND: Caffeine is a methyl derivative of xanthine which is a naturally occurring chemical found in leaves, seeds and fruits of over 60 species of plants. People of all ages use this 'miracle foods' in attempts to improve athletic performance, alter body composition and increased levels of energy. Many studies have reported no significant effect of caffeine on the cardiovascular system. On the contrary several other studies reported significant effect on the cardiovascular system. Some studies have shown no dose response relationship between caffeine and cardiovascular system. The objective of this study was to determine the effect of varied doses of caffeine on cardiovascular system of apparently healthy black African adults.

METHODS: A repeated measure of 4 randomized crossover (counterbalanced) double blind design was used. The total study period was 4 weeks of once weekly test. One hour post caffeine (5, 10 and 15mg/kg body weight) and placebo doses ingestion cardiovascular parameters including Systolic Blood Pressure, Diastolic Blood Pressure and Heart Rate were assessed. Repeated measures ANOVA was used to assess the level of significance in all variables of interest at the level of significance of 5%.

RESULT: Twenty subjects with mean age of 22.3 (SD±4.0) years participated in the study. Five, ten and 15mg/kg doses of coffee and placebo of coffee and caffeine free was used. The result showed no significant effect of the 3 doses of caffeine over placebo in all cardiovascular parameters (P<0.05).

CONCLUSION: the finding of this study demonstrated that instant soluble coffee dose up to approximately 9499mg (caffeine content of 889mg) seems not to stress the cardiovascular system of normal African black adults'.