Currently I am base building but am running only around 30-35 miles a week. I hope to be in the mid-40’s by late September. Since the first week of July, all of my efforts have been targeted at a pace below AeT. I believe my that my AeT is 171 and my AnT is 183, or about a ~7% spread. Over the course of the past three months, my perception of effort seems to correspond with these numbers.. I’m probably due for another test all the same.
The thing is, my heart rate seems to be fairly static for a huge chunk of my easy pace zones. It hovers around 156-158 at what ought to be a Z1 pace (slower than 9:50 min/mi). all the way down to around 8:15-8:30 min/mi. This heart rate is still Z2 for me, but it’s made it really hard to get Z1 work in.
I live in Texas and most of my runs are late in the afternoon, so I’m usually dealing with temps of 91+ and humidities in the mid 30’s at that time of day. When I do work in morning runs, I usually am able to keep it under 150 for a while but I typically wind up hovering in that 156-158 territory by the end of the run.
I should note that these numbers have been reasonably consistent as measured by both a chest strap and a watch. I start to see climbing HR’s above the 8:15 area, but it almost feels like my proverbial speedometer is broken up until that point.
I did have a really wonderful outlier run earlier this week as a storm was blowing in, and my watch recorded an average HR of 138 as I progressed from an 8:26/mi down to a 7:23 over 6 miles. I wrote that off as a trash data because of the wrist based HR, but the conditions were as nice as they’ve been in months and my perception of the effort was easy, so I haven’t been able to shake the thought that the heat and humidity is just messing with my HR and that those numbers might be more accurate than I’m giving them credit for.
This isn’t the first time I’ve posted here about interpreting heart rate data in heat, so I hope I’m not beating a dead horse. Has anyone else had similar issues living in the south? I’d love any tips some of you may have for training in the heat. Should I go as slow as is necessary to keep in Z1? Thanks for reading and I appreciate any thoughts from the communnity.