What kind of HR is sustainable for 65-70 minutes in a half marathon? I have heard 88-91 percent.
Unfortunately, this is going to be difficult to gauge because my heart rate tends to drift up significantly over time. So if I averaged 84 percent for the first mile I might average 95 percent for the final mile at the same pace. Because of this, I don't plan to use the HR monitor to pace my half. I am going to go on RPE and splits. But I will wear the strap to view the data afterwards.
However, I'm curious if people have had good or bad experiences using HR to monitor effort in longer races and efforts.