Comparative effects of caffeine & L-Theanine consumption on subjective cardiovascular signs and Neurophysiological responses.

Abstract

Non-alcoholic beverages comprise of Caffeine and L-theanine as core ingredients. Caffeine is attributed to augment cardiovascular and neurophysiological responses by enhancing the neurotransmission of catecholamines after binding with adenosine receptors antagonistically. L-theanine, as a constituent of green tea is helpful in lowering blood pressure by antagonizing the effects of excitatory neurotransmitters after subsequent release of inhibitory neurotransmitter GABA. 87 healthy females with age 18-19 years, participated in the study were divided into three different groups. Group A was subjected to consume cold beverage (soft drink). Participants of group B & C were allowed to take hot beverages in the form of tea and green tea respectively. Cardiovascular parameters and neurophysiological responses were assessed before and after 45 minutes of beverages intake.Statistical analysis revealed a significant improvement in the reaction time of tea and in concentration test of both tea and green tea consumers. In addition, a less significant increase in HR with tremendous decrease in PR was observed among green tea consumers. Furthermore, significant reduction in both systolic & diastolic blood pressure was evident with green tea consumers.Experimental results are unveiling effectiveness of L-theanine over caffeine in lowering BP, HR & PR after antagonizing the release of excitatory neurotransmitter along with the opening of ligand gated chloride channels that leads to hyperpolarization. Moreover, a favorable combination of caffeine & L-theanine is responsible for enhancing cognitive performances, alertness and well being.