Java junkie joy! Coffee can ease pain of exercise By Michael Lasalandra Tuesday, September 16, 2003   Your morning cup o' Joe may do more than get you going. It may help blunt the pain of any exercise you do later.      Researchers at the University of Georgia report caffeine was able to reduce levels of muscle pain felt by volunteers who did strenuous cycling exercises.      ``This could be one way to feel a little less muscle pain when you work out,'' said Patrick O'Connor, professor of exercise science.      The researchers had tested aspirin on exercising volunteers and reported that it had no effect on reducing muscle pain.      ``Muscle contractions produce a host of biochemicals that can stimulate pain,'' he said. ``Aspirin blocks only one of those chemicals. And apparently the biochemical blocked by aspirin has little role in exercise-induced muscle pain.''      O'Connor said caffeine blocks a biochemical known as adenosine that is produced during vigorous exercise.      The paper, published in the Journal of Pain, tested 16 volunteers who cycled for 30 minutes on two separate days. The exercise was designed to make their thigh muscles hurt. Subjects took either a caffeine pill or a placebo pill about an hour before the workout. Those who took the caffeine pill reported substantially less pain.