Having read and considered marco83 's excellent Belfast Marathon 2019 report, I went out this morning to do a simple 5Km training run. I set out deliberately to watch my heart rate, as this is one of three bio-metrics that I can easily monitor 'in-run', the others are pace and stride. I set out intending to use pace and stride to maintain heart-rate below 130. My VO2Max sits around 42 ml/kg/min, which Garmin says is excellent for men of my age (69). My Max Heart Rate over the last 3 months is about 177, and my resting heart rate (approved by my doctor) is low at 45.
As always, as a run goes on, my heart rate rises, usually I get to some point and it skyrockets and I feel very tired, but today I think I managed to keep in under control. Certainly at the end of 5.5Km I felt I could go on forever at that pace.
I'll try it again on Thursday. I think the next topic I need to understand is in-run nutrition and hydration. Any thoughts would be interesting.