Heart Rate During Ultramarathons

A couple of weeks ago my friend, Greg Loomis, asked about heart rate zones appropriate for ultramarathon training. Having trained consistently with with a heart rate monitor (HRM) for the past four years, and having run a few ultras during that time, I thought I might be able to shed some light on the subject. In this article, I present and discuss heart rate data from marathon and popular ultramarathon distances: 26.2 mi, 50 km, 50 mi, 100 km, and 100 mi. The data I present are from races, each run at an “all-out