I usually run high 4:20s and low 4:30s for my 1600m runs when competing. Yesterday I ran 4:55 and barely beat the second place runner. I can run local meets where there is no competition at 4:40s no problem, but yesterday I had to struggle to keep up even a 4:55. We went to the doctor that evening and nothing was wrong exept my heart rate was still 83 when my usual resting is 48. I had the flu three weeks prior but still managed a 4:34 and 4:29 during the week I had it. I had gotten adaquate sleep and food/hydration the days and night before. I don't use alcohol or drugs either. We have states coming soon and I can't figure out what the problem was. Any thoughts?