title_body: Is coffee good to consume before sport?
upvoted_answer: There are studies that have shown a marked increase in performance compared to a placebo in athletes who drank coffee before a workout. Both strength and endurance exercises saw improvement. As to the diruretc and constructive effects, it would seem that staying hydrated (which you should do anyway when exercising) is an effective way to combat the nominal downsides.
  Below are the studies in question. 
  
  al., G.M.S.e., Effect of caffeine on sport-specific endurance performance: A systematic review. . Journal Strength and Conditioning Research, 2009. 23(1): p. 315-24.
  
  Astorino, T.A., R.L. Rohmann, and K. Firth, Effect of caffeine ingestion on one-repetition maximum muscular strength. Eur J Appl Physiol, 2008. 102(2): p. 127-32.