Lower heart rate

[Latege]

Anyone got any suggestions as to why my heart rate was much lower than usual when I went for a run today? I went out for a steady trot (about 4.5 miles), ended up running slightly faster than usual even though the paths were very muddy and slippery but my average heart rate was at least 15 bpm less than usual. Even going up a sharp incline it only got up to 139 (would usually be over 150 on that particular stretch). I'm not particularly concerned, more curious as to what could cause this oddity.
Of course it could be that the heart rate monitor was playing up, but usually when it does that it becomes totally erratic, jumping up and down rapidly. Today it stayed consistently lower than usual. And I did take my pulse manually at the end of the run and it was roughly the same as the hrm reading at that point so it doesn't seem like a technical glitch.

[The Hat]

Youre are getting fitter ?

[Mike T]

I would be happy if I was you! It does suggest that you are reaping the rewards of the work you did several weeks back.

[Latege]

I would be happy if I was you! It does suggest that you are reaping the rewards of the work you did several weeks back.

Youre are getting fitter ?

So much overnight? I few beats per minute I could understand but 15 (actually it's more like 18) seems a bit much from one day to the next. It'll be interesting to see what happens next time I'm out.

[dylan]

check your diary,you may be doing something right in that you are getting fitter and have recovered well and not overtrained/over raced.

[noel]

But were you as fast as normal?

[Latege]

But were you as fast as normal?

Yes, actually slightly faster despite the muddy, slippery conditions.

But my new-found fitness only lasted 24 hours. It's hard to compare today's run since I deliberately varied the pace some (so "average" is not really average) but my heart rate was definitely back to normal or close to it. Probably be Fri. or Sat. before I do another steady run so I'll see what happens then, but I've not done any different "training" (I just run really) than I've done for years.