Help with HR zone training
I have just completed a turbo brick session & set off on my run on zone 1 very comfortably, my heart rate remained in zone 1 (sometimes entering no zone) for 3-4 minutes then it shot up to a heart rate of 158 which is getting close to the top end of my zone 2 even though I wasn't putting anymore effort in, the terrain was the same and I as running at the same pace & really comfortable! My heart rate then went into the bottom end of my zone 3 (164) but again I wasnt changing my pace. I'm frustrated and confused. I really want to train using heart rate zones as i have heard so many good things about it and i'm training for a half ironman but I just feel like its not working.
Any advice would be appreciated. Thanks
Is the time it takes for your heart rate to raise any different than the first few mins of a 30 mins run?
If your only doing 5-10 min runs you cant really train using heart rate