I am absolutely intrigued and delighted by the results of this study. However, I do have one question/concern... The time used as the "morning" variable was 10:00 am. I understand that this is a typical time for highly trained athletes first workout of the day, but is it (10:00 am) truly indicative of a "morning" workout?

Given the potential application of the results to the "real world" (the other 95% of us), I would be interested in viewing results of control group versus placebo groups at 6:00/7:00 am. I wonder if 3-4 hours earlier would increase the effect/relevance of body temperature relative to the dosing of caffeine?

I would REALLY like to see this! I have been conducting my own "self" experiments for about two years now, and have not been able to substitute the effectiveness of the afternoon/evening workouts with caffeine so early in the morning. I have noticed however (in myself), that there is not a "huge" difference between a 10/11 am workout versus a 5/6 pm workout. I will say, however, that caffeine seemingly levels out the playing field.

Anyways, thoughts on the effect of caffeine on a 6:00/7:00 am workout would be greatly appreciated.