Caffeine is a bronchodilator, so in some circumstances it might decrease the work of breathing.I have read several studies(OK I read just the summaries-skipped al the BS statistics,methods etc)over the years,and they usually showed that caffeine improves athletic performance-max lifts and endurance efforts.It is banned(I think)-at higher levels-in the Olympics for just this reason.
I swill 2 very,very strong cups of coffee every am to pry my lids open.It is a great drug-cheap,effective,legal with a minimal downside-mild abstinence syndrone,diuretic,slight tremor etc.Several studies have linked coffee-caffeinated brewed coffee-with lower cancer rates.I wouldn't count on that,but...Thanks.Charlie