Actually, now that I can see that last post about caffeine, the headline makes it all look a bit scary, when in fact caffeine is not all bad for endurance athletes.
One of the reasons I’ve weaned myself off fully-leaded coffee is to make the effects of caffeine more marked when I do have it. I can’t cite the many research papers here, but it’s well-known that caffeine can boost endurance considerably – or certainly by an amount that makes a difference on a long effort. That’s why you can buy gels and sports drinks with caffeine added.
The obvious benefit is the mental stimulus/lift that it can give when the going gets tough. But what lots of people don’t realise is that it seems to mobilise free fatty acids, making them more easily available for use for muscle contraction and general energy production. This would preserve your precious glycogen stores. And the longer your glycogen stores last in an endurance event, the better!
There’s more to it than that, but if you want more, google ‘caffeine endurance performance’ and there’ll be plenty for you to read.