In reply to TimB:
> That information is from 1995. The 2015 WADA list does not list caffeine as a prohibited substance, but does note
Yes, here in Australia it WAS banned but not now. There was a famous case from the 1988 Olympics of Alex Watson, a fencer, banned because of the caffeine levels in his blood. Iirc he freely admitted to drinking more than a dozen cups of coffee a day.
http://www.abc.net.au/news/stories/2008/08/02/2322263.htm?site=olympics/200...
Personally I like caffeine and use it. I can go without it, but choose not to. Endurance is definitely enhanced, but in my experience from what I can tell there is a mental element to that more than physical. It seems to make it easier to set your mind on mindless repetitive effort, good for mountaineering and polar skiing, and probably cycling too. I find my focus is better and my mind doesn't wander as it usually does.
From my experience and that of others I've found that on a really long bout of effort - adventure racing or polar skiing etc - where you really exhaust your glycogen supplies and are near the edge of reserves and effort, a caffeine hit from a gel has a real impact and is a notable performance enhancer.
However it's also a vasoconstrictor and I've found that if I overdo it, either too many gels or gels + dark chocolate or strong tea etc, in very cold temps it is noticeably harder to keep my fingers warm. Which does not enhance performance at all.
Post edited at 13:01