I have been running fairly regularly for the last year and have been building up my distance (15 mile route at least twice a week). In january this year I was put on Beta Blockers by my GP for high Blood Pressure. Since then I have been unable to run anywhere near the distance I used to and can now only manage about 4 or 5 miles before i have to stop. Has anyone out there got any advice or had the same problem. It's really starting to p*ss me off now.