Tom, there was a study done at the Department of Veterinary Clinical
Sciences, College of Veterinary Medicine, The Ohio State University about beta
blockers and glucose utilization. I only looked at it briefly but it appears
that slowing the heart rate didn't help endurance. I think they felt it
demotivated the horse. You can read the study at: http://jap.physiology.org/cgi/content/full/89/3/1086.
