About a year ago I found out I had Gilberts Syndrome. It cause my bilirubin levels to be increased and is found in about 5% in the population. My doctor said its relatively harmless and there isn't much known about it. Recently I found out that ATP Tour player Alexander Dopogolov also has Gilberts Syndrome.(LINK: http://www.nst.com.my/sports/other/tennis-gilbert-s-syndrome-fails-to-floor-dolgopolov-1.148908) After reading through it he claims that his Gilbert makes him extremley fatigued and tired when playing tennis. I'm 19 years old, 5 foot 11 and about 165 pounds and I've always been in pretty good shape but whenever I play tennis and there is a lot of movement and running I find myself tiring out extremley quickly. I breath extremley heavy and can't continue my pace. I'm just now starting to wonder if it's the Gilberts Syndrome that really impairs my endurance on the court. I can run a decent mile time (7.5 Min Mile) and do things fine where the pace is steady (although I do breath heavy) but tennis can really kill me sometimes. Lately I've been having my best success using a more grinding and counter punching style of tennis. But I find I drop off a lot as soon as theres a lot of running and I can't keep it up. Should I try to focus on shortening points a little more? I was thinking of focusing on a big serve and forehand (considering those are my best shots.) Or should I try to focus on my fitness a little more? Any advice tt?