Green Tea Extract, Caffeine, and High-Intensity Exercise: Ultimate Ripped Stack
by: Robbie Durand
Thermogenesis is the process of heat production in living organisms that can facilitate the fat burning process. There are many ingredients in most over the counter fat burners. Of these bioactive compounds, caffeine and green tea catechins of various plant extracts remain arguably as the main ingredients found in thermogenic supplements today. In this month’s prestigious Journal of Strength and Conditioning Research reported in the study titled, “Dietary Caffeine And Polyphenol Supplementation Enhances Overall Metabolic Rate And Lipid Oxidation At Rest And After A Bout Of Sprint Interval Exercise” that caffeine and green tea extract increased post-exercise fat oxidation after sprint exercise by 10%. Green tea extract high thermogenic properties could potentially reside in an interaction between its high content in catechin-polyphenols and caffeine with sympathetically increases the fat burning hormone noradrenaline. Green tea polyphenols are recognized to be capable of inhibiting catechol-O-methyl-transferase (the enzyme that degrades noradrenaline). Caffeine has been found inhibit phosphodiesterases (enzymes that break down noradrenaline -induced cAMP); it is assumed that the green tea extract, via its catechin-polyphenols and caffeine, is effective in stimulating thermogenesis by reducing inhibition at different control points along the noradrenaline -cAMP axis. This synergistic interaction between catechin-polyphenols and caffeine that augment and prolong sympathetic stimulation of thermogenesis.
Green Tea Polyphenols Increase Post-Exercise Fat Oxidation
Fat oxidation has been shown to increase after short-term green tea extract ingestion and after one bout of intermittent sprinting exercise. Researchers investigated the combined effect of short-term green tea extract and a single session of intermittent sprinting exercise upon post-exercise fat oxidation. Fourteen women consumed three green tea extract or placebo capsules the day before and one capsule 90 minutes before a 20-minute of intermittent sprinting cycling protocol followed by 1 hour of resting recovery. Fat oxidation was calculated using indirect calorimetry. At the end of the study, there was a significant increase in fat oxidation post-exercise compared to at rest in the placebo condition. After green tea extract ingestion, however, at rest and post-exercise, fat oxidation was significantly greater than that after placebo. Plasma glycerol levels at rest and 15 minutes during post-exercise were substantially higher after green tea extract consumption compared to placebo. Compared to placebo, plasma catecholamines increased significantly after green tea extract consumption and 20 minutes after intermittent sprinting exercise. Acute green tea extract ingestion significantly increased fat oxidation under resting and post-exercise conditions when compared to placebo. Based on previous research, it’s known that green tea extract combined with high-intensity interval training can increase fat oxidation, but what are the effects of green tea combined with caffeine.
When green tea extract and caffeine are combined, they operate synergistically to enhance metabolism, fat oxidation, and ultimately facilitate weight loss. Previous research has found that a combined treatment of a catechin polyphenol-caffeine mixture has shown to induce a significantly greater thermogenic response than an equivalent amount of caffeine. Researchers wanted to examine what happens to fat oxidation when they combined green tea extract and caffeine combined with high-intensity sprint training. Subject were administered 250mg of caffeine + 400 mg of a green tea extract with 50% EGCG and on metabolic rate and fat oxidation at rest, as well as following a bout of sprint interval exercise. At the end of the study, during the resting state, a single dosing of green tea extract and caffeine induced an approximate 8% rise in energy expenditure with an increase in oxygen uptake. Accompanying this thermogenic response was a 10% increase in fat oxidation rate. Specifically, post-sprint exercise energy expenditure was approximately 10% greater with pre-exercise caffeine-polyphenol supplementation versus placebo. The results suggest that increased lipid oxidation rate following sprint interval exercise is further amplified with a single caffeine-polyphenol dosing.
This is a great study showing the synergistic effect of combining caffeine and green tea extract with high intensity exercise can enhance fat oxidation.